removed unused latex stuff

1 files changed, 0 insertions, 6849 deletions

diff --git a/texmf/source/latex/revtex/ltxgrid.dtx b/texmf/source/latex/revtex/ltxgrid.dtx
deleted file mode 100644
index 6d0c659..0000000
--- a/texmf/source/latex/revtex/ltxgrid.dtx
+++ /dev/null
@@ -1,6849 +0,0 @@
-% \iffalse meta-comment balanced on line 109
-% ltxgrid.dtx: package to change page grid, MVL.
-% Copyright (c) 2009 Arthur Ogawa
-%
-% Disclaimer
-%   This file is distributed WITHOUT ANY WARRANTY;
-%   without even the implied warranty of
-%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-% License
-%   You may distribute this file under the conditions of the 
-%   LaTeX Project Public License 1.3c or later 
-%   (http://www.latex-project.org/lppl.txt).
-% ReadMe
-%   For the documentation and more detailed instructions for
-%   installation, typeset this document with \LaTeX.
-% Maintenance Status
-%   This work has the LPPL maintenance status "maintained";
-%   Current Maintainer of this work is Arthur Ogawa
-%   changes for version 4.2d and 4.2e by Phelype Oleinik.
-%
-% This work consists of the main source file ltxgrid.dtx
-% and the derived files
-%    ltxgrid.sty, ltxgrid.pdf
-% Distribution:
-%    CTAN:macros/latex/contrib/revtex/
-%
-% Unpacking:
-%    tex ltxgrid.dtx
-%
-% Documentation:
-%    latex ltxgrid.dtx; ...
-%
-%    Programm calls to get the documentation (example):
-%       pdflatex ltxgrid.dtx
-%       makeindex -s gind.ist ltxgrid
-%       makeindex -s gglo.ist -o ltxgrid.gls ltxgrid.glo
-%       pdflatex ltxgrid.dtx
-%       makeindex -s gind.ist ltxgrid.idx
-%       pdflatex ltxgrid.dtx
-%
-% Installation:
-%    TDS:doc/latex/revtex/
-%    TDS:tex/latex/revtex/
-%    TDS:source/latex/revtex/
-%
-% Thanks, Heiko!
-%    This method of letting a single .dtx file serve as both
-%    documentation (via latex) and installer (via tex) follows
-%    the example of Heiko Oberdiek. Thanks!
-%<*ignore>
-\begingroup
-  \def\x{LaTeX2e}%
-\expandafter\endgroup
-\ifcase
- 0\expandafter\ifx\csname processbatchFile\endcsname\relax\else1\fi\ifx\fmtname\x\else 1\fi
- \relax
-\else
- \csname fi\endcsname
-%</ignore>
-%<*install>
-%% This file will generate documentation and runtime files
-%% from ltxgrid.dtx when run through LaTeX or TeX.
-\input docstrip
-\preamble
-
-This is a generated file;
-altering it directly is inadvisable;
-instead, modify the original source file.
-See the URL in the file README-LTXGRID.tex.
-
-License
-   You may distribute this file under the conditions of the 
-   LaTeX Project Public License 1.3c or later 
-   (http://www.latex-project.org/lppl.txt).
-   
-   This file is distributed WITHOUT ANY WARRANTY; 
-   without even the implied warranty of MERCHANTABILITY 
-   or FITNESS FOR A PARTICULAR PURPOSE.
-
-\endpreamble
-\askforoverwritefalse
-\keepsilent
- \generate{%
-  %{ignore}
-% \usedir{tex/latex/revtex}%
-  \file{ltxgrid.sty}{%
-   \from{ltxgrid.dtx}{package,kernel}%
-  }%
- }%
-\ifToplevel{
-\Msg{***********************************************************}
-\Msg{*}
-\Msg{* To finish the installation, please move}
-\Msg{*    ltxgrid.sty}
-\Msg{* into a directory searched by TeX;}
-\Msg{* in a TDS-compliant installation:}
-\Msg{* texmf/tex/macros/latex/revtex/.}
-\Msg{*}
-\Msg{* To produce the documentation,
-       run ltxgrid.dtx through LaTeX.}
-\Msg{*}
-\Msg{* Happy TeXing}
-\Msg{***********************************************************}
-}
-\endbatchfile
-%</install>
-%<*ignore>
-\fi
-%</ignore>
-% \fi
-%
-% \GetFileInfo{ltxgrid.dtx}
-%
-% \iffalse ltxdoc klootch
-%<*package>
-%%%  @LaTeX-file{
-%%%     filename        = "ltxgrid.dtx",
-%%%     version         = "4.2e",
-%%%     date            = "2020/10/03",
-%%%     author          = "Arthur Ogawa (mailto:arthur_ogawa at sbcglobal.net),
-%%%                        Phelype Oleinik (mailto:phelype.oleinik at latex-project.org),
-%%%                        commissioned by the American Physical Society.
-%%%                        ",
-%%%     copyright       = "Copyright (C) 1999, 2009 Arthur Ogawa,
-%%%                        distributed under the terms of the 
-%%%                        LaTeX Project Public License 1.3c, see
-%%%                        ftp://ctan.tug.org/macros/latex/base/lppl.txt
-%%%                        ",
-%%%     address         = "Arthur Ogawa,
-%%%                        USA",
-%%%     telephone       = "",
-%%%     FAX             = "",
-%%%     email           = "mailto colon arthur_ogawa at sbcglobal.net",
-%%%     codetable       = "ISO/ASCII",
-%%%     keywords        = "latex, page grid, main vertical list",
-%%%     supported       = "yes",
-%%%     abstract        = "package to change page grid, MVL",
-%%%  }
-%</package>
-% \fi
-%
-% \iffalse ltxdoc klootch
-% The following references the \file{README-LTXGRID} file,
-% which contains basic information about this package.
-% The contents of this file are generated when
-% you typeset the programmer's documentation.
-% Search on "{filecontents*}{README-LTXGRID}" to locate it.
-% \fi\input{README-LTXGRID}%
-%
-% \subsection{Bill of Materials}
-%
-% Following is a list of the files in this distribution arranged
-% according to provenance.
-%
-% \subsubsection{Primary Source}%
-% One single file generates all.
-%\begin{verbatim}
-%ltxgrid.dtx
-%\end{verbatim}
-%
-% \subsubsection{Generated by \texttt{latex ltxgrid.dtx}}%
-% Typesetting the source file under \LaTeX\
-% generates the readme and the installer.
-%\begin{verbatim}
-%README-LTXGRID   ltxgrid.ins
-%\end{verbatim}
-%
-% \subsubsection{Generated by \texttt{tex ltxgrid.ins}}%
-% Typesetting the installer generates
-% the package files.
-%\begin{verbatim}
-%ltxgrid.sty
-%\end{verbatim}
-%
-% \subsubsection{Documentation}%
-% The following are the online documentation:
-% \begin{verbatim}
-%ltxgrid.pdf
-% \end{verbatim}
-%
-% \subsubsection{Auxiliary}%
-% The following are auxiliary files generated
-% in the course of running \LaTeX:
-% \begin{verbatim}
-%ltxgrid.aux ltxgrid.idx ltxgrid.ind ltxgrid.log ltxgrid.toc
-% \end{verbatim}
-%
-% \section{Code common to all modules}%
-%
-% The following may look a bit klootchy, but we
-% want to require only one place in this file
-% where the version number is stated,
-% and we also want to ensure that the version
-% number is embedded into every generated file.
-%
-% Now we declare that
-% these files can only be used with \LaTeXe.
-% An appropriate message is displayed if
-% a different \TeX{} format is used.
-%    \begin{macrocode}
-%<*driver|package>
-\NeedsTeXFormat{LaTeX2e}[1995/12/01]%
-%</driver|package>
-%    \end{macrocode}
-% As desired, the following modules all
-% take common version information:
-%    \begin{macrocode}
-%<kernel&!package&!doc>\typeout{%
-%<*package|doc>
-\ProvidesFile{%
-%</package|doc>
-%<*kernel|package|doc>
-ltxgrid%
-%</kernel|package|doc>
-%<*doc>
-.dtx%
-%</doc>
-%<package>.sty%
-%<*package|doc>
-}%
-%</package|doc>
-%    \end{macrocode}
-%
-% The following line contains, for once and for all,
-% the version and date information.
-% By various means, this information is reproduced
-% consistently in all generated files and in the
-% typeset documentation.
-% Give credit where due. 
-%    \begin{macrocode}
-%<*doc|package|kernel>
-%<version>
- [2020/10/03 4.2e page grid package (portions licensed from W. E. Baxter web at superscript.com)]% \fileversion
-%</doc|package|kernel>
-%<kernel&!package&!doc>}%
-%    \end{macrocode}
-%
-%
-% \section{The driver module \texttt{doc}}
-%
-% This module, consisting of the present section,
-% typesets the programmer's documentation,
-% generating the \file{.ins} installer and \file{README-LTXGRID} as required.
-%
-% Because the only uncommented-out lines of code at the beginning of
-% this file constitute the \file{doc} module itself,
-% we can simply typeset the \file{.dtx} file directly,
-% and there is thus rarely any need to
-% generate the ``doc'' {\sc docstrip} module.
-% Module delimiters are nonetheless required so that
-% this code does not find its way into the other modules.
-%
-% The \enve{document} command concludes the typesetting run.
-%
-%    \begin{macrocode}
-%<*driver>
-%    \end{macrocode}
-%
-% \subsection{The Preamble}
-% The programmers documentation is formatted
-% with the \classname{ltxdoc} class with local customizations,
-% and with the usual code line indexing.
-%    \begin{macrocode}
-\documentclass{ltxdoc}
-\RequirePackage{ltxdocext}%
-\RequirePackage[colorlinks=true,linkcolor=blue]{hyperref}%
-%\ifx\package@font\@undefined\else
-% \expandafter\expandafter
-% \expandafter\RequirePackage
-% \expandafter\expandafter
-% \expandafter{%
-%              \csname package@font\endcsname
-%             }%
-%\fi
-\CodelineIndex\EnableCrossrefs % makeindex -s gind.ist ltxgrid
-\RecordChanges % makeindex -s gglo.ist -o ltxgrid.gls ltxgrid.glo
-%    \end{macrocode}
-%
-% \subsubsection{Docstrip and info directives}
-%    We use so many {\sc docstrip} modules that we set the
-%    \texttt{StandardModuleDepth} counter to 1.
-%    \begin{macrocode}
-\setcounter{StandardModuleDepth}{1}
-%    \end{macrocode}
-%    The following command retrieves the date and version information
-%    from this file.
-%    \begin{macrocode}
-\expandafter\GetFileInfo\expandafter{\jobname.dtx}%
-%    \end{macrocode}
-%
-% \subsection{The ``Read Me'' File}
-% As promised above, here is the contents of the
-% ``Read Me'' file. That file serves a double purpose,
-% since it also constitutes the beginining of the
-% programmer's documentation. What better thing, after
-% all, to have appear at the beginning of the
-% typeset documentation?
-%
-% A good discussion of how to write a ReadMe file can be found in
-% Engst, Tonya, ``Writing a ReadMe File? Read This''
-% \emph{MacTech} October 1998, p. 58.
-%
-% Note the appearance of the
-% \cmd\StopEventually\ command, which marks the
-% dividing line between the user documentation
-% and the programmer documentation.
-%
-% The usual user will not be asked to
-% do a full build, not to speak
-% of the bootstrap.
-% Instructions for carrying these processes
-% begin the programmer's manual.
-%
-%    \begin{macrocode}
-\begin{filecontents*}{README-LTXGRID}
-\title{%
- A \LaTeX\ Package for changing the page grid and MVL%
- \thanks{%
-  This file has version number \fileversion,
-  last revised \filedate.%
- }%
- \thanks{%
-  Version \fileversion\ \copyright\ 2019--2020 American Physical Society
- }%
-}%
-\author{%
- Arthur Ogawa%
-  \thanks{\texttt{mailto:arthur\_ogawa at sbcglobal.net}}%
-}%
-%\iffalse
-% For version number and date,
-% search on "\fileversion" in the .dtx file,
-% or see the end of the README-LTXGRID file.
-%\fi
-\maketitle
-
-This file embodies the \classname{ltxgrid} package,
-the implementation and its user documentation.
-
-The distribution point for this work is
-\url{journals.aps.org/revtex},
-which contains the REV\TeX\ package, and includes source and documentation for this package.
-
-The \classname{ltxgrid} package was commissioned by the American Physical Society
-and is distributed under the terms of the \LaTeX\ Project Public License 1.3c,
-the same license under which all the portions of \LaTeX\ itself is distributed.
-Please see \url{http://ctan.tug.org/macros/latex/base/lppl.txt} for details.
-
-To use this document class, you must have a working
-\TeX\ installation equipped with \LaTeXe\ 
-and possibly pdftex and Adobe Acrobat Reader or equivalent.
-
-To install, retrieve the distribution,
-unpack it into a directory on the target computer,
-into a location in your filesystem where it will be found by \LaTeX;
-in a TDS-compliant installation this would be:
-\file{texmf/tex/macros/latex/revtex/.}
-
-To use, read the user documentation \file{src/ltxgrid.pdf}.
-
-\tableofcontents
-
-\section{Processing Instructions}
-
-The package file \file{ltxgrid.sty}
-is generated from this file, \file{ltxgrid.dtx},
-using the {\sc docstrip} facility of \LaTeX
-via |tex ltxgrid.dtx|.
-The typeset documentation that you are now reading is generated from
-this same file by typesetting it with \LaTeX\ or pdftex
-via |latex ltxgrid.dtx| or |pdflatex ltxgrid.dtx|.
-
-\subsection{Build Instructions}
-
-You may bootstrap this suite of files solely from \file{ltxgrid.dtx}.
-Prepare by installing \LaTeXe\ (and either tex or pdftex) on your computer,
-then carry out the following steps:
-\begin{enumerate}
-\item
-Within an otherwise empty directory,
-typeset \file{ltxgrid.dtx} with \TeX\ or pdftex;
-thereby generating the package file \file{ltxgrid.sty}.
-
-\item
-Now typeset \file{ltxgrid.dtx} with \LaTeX\ or pdflatex;
-you will obtain the typeset documentation you are now reading,
-along with the file \file{README-LTXGRID}.
-
-Note: you will have to run \LaTeX\ twice, then \file{makeindex}, then
-\LaTeX\ again in order to obtain a valid index and table of contents.
-
-\item
-Install the following files into indicated locations within your 
-TDS-compliant \texttt{texmf} tree (you may need root access):
-\begin{itemize}
-\item
-\file{$TEXMF/}\file{tex/}\file{latex/}\file{revtex/}\classname{ltxgrid.sty}
-\item
-\file{$TEXMF/}\file{source/}\file{latex/}\file{revtex/}\classname{ltxgrid.dtx}
-\item
-\file{$TEXMF/}\file{doc/}\file{latex/}\file{revtex/}\classname{ltxgrid.pdf}
-\end{itemize}
-where \file{TEXMF/} stands for \file{texmf-local/}, or some other \texttt{texmf} tree in your installation.
-\item
-Run \texttt{mktexlsr} on directory \file{$TEXMF/} (you may need root access).
-\item
-Build and installation are now complete; 
-now put a \cmd\usepackage\texttt{\{ltxgrid\}} in your document preamble!
-(Note: \texttt{ltxgrid} requires package \texttt{ltxutil}.)
-\end{enumerate}
-
-\subsection{Change Log}
-\changes{4.0a}{2001/06/18}{Introduce \cs{marry@height} }
-\changes{4.0a}{2001/06/18}{Introduce \cs{set@marry@height} }
-\changes{4.0a}{2008/06/26 }{\cs{@yfloat}: de-fang \cs{set@footnotewidth} (see ltxutil.dtx): we have already done its job. }
-\changes{4.1a}{2008/06/29}{Change \cs{LT@array@new}: restore \cs{@tabularcr} and \cs{@xtabularcr}}
-\changes{4.1a}{2008/06/29}{Change \cs{LT@array@new}: set \cs{LT@LL@FM@cr} to \cs{@arraycr@array} instead of \cs{@arraycr}}
-\changes{4.1a}{2008/06/29}{Repair error in \cs{endlongtable@new} involving \cs{@ifx}: argument not delimited.}
-\changes{4.1b}{2008/08/04}{Get rid of the \cs{reserved@a} idiom}
-\changes{4.1b}{2008/08/04}{Turn off the \cs{set@footnotewidth} mechanism; a float `knows' its proper typesetting context}
-\changes{4.1b}{2008/08/04}{(AO, 452) Support length checking: show size of shipped out text.}
-\changes{4.1b}{2008/08/04}{(AO, 456) Compatibility with other packages that override the output routine, following suggestion by David Kastrup.}
-\changes{4.1b}{2008/08/04}{}
-\changes{4.1b}{2008/08/04}{Box \cs{footbox} changed to box \cs{footsofar}}
-\changes{4.1b}{2008/08/04}{Change \cs{@combinepage} to \cs{@combinepage} with argument}
-\changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-\changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-\changes{4.1b}{2008/08/04}{New procedure \cs{@iffpsbit} replaces \cs{@getfpsbit}}
-\changes{4.1b}{2008/08/04}{New procedure \cs{@output@combined@page}}
-\changes{4.1b}{2008/08/04}{New procedure for showing a box contents, \cs{trace@box}}
-\changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@head} headpatches \cs{@outputpage}}%
-\changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@tail} tailpatches \cs{@outputpage}}%
-\changes{4.1b}{2008/08/04}{Procedure \cs{balance@2} defined more transparently}%
-\changes{4.1b}{2008/08/04}{Tally the height of the float}
-\changes{4.1b}{2008/08/04}{Use \cs{document@inithook} instead of \cs{AtBeginDocument}}
-\changes{4.1b}{2008/08/04}{Use \cs{trace@box} instead of \cs{showbox}}
-\changes{4.1f}{2009/07/07}{(AO, 515) Prevent line numbering within a footnote}
-\changes{4.1f}{2009/07/10}{(AO, 518) Tally register overflow when locument is long}
-\changes{4.1f}{2009/07/14}{(AO, 519) \cs{footins} content must be preserved and reintegrated}
-\changes{4.1f}{2009/07/15}{(AO, 519) Preserve footnotes that are in \cs{footsofar} across a page grid change}
-\changes{4.1g}{2009/10/06}{(AO, 531) Fix package \classname{float} }
-\changes{4.1n}{2009/12/02}{Restore the \cs{lastbox} if it is not a footnote}
-\changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-\changes{4.1n}{2009/12/18}{(AO, 571) Deconstruct balanced footnotes when needed}
-\changes{4.1n}{2010/01/02}{(AO, 571) Interface \cs{set@footnotewidth} for determining the set width of footnotes}%
-\changes{4.1n}{2010/01/02}{(AO, 571) Footnotes, when columns are balanced or when they are composed with their column}%
-\changes{4.1n}{2010/01/02}{(AO, 571) Abandon \cs{recover@footins} in favor of \cs{recover@column}}%
-\changes{4.1n}{2010/01/02}{(AO, 571) Use procedures \cs{output@do@prep} and \cs{output@column@do} as dispatchers}
-\changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-\changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-\changes{4.1n}{2010/01/02}{(AO, 571) footnote rule is leaders, so that it may be removed by \cs{vsplit}; mechanism of \cs{kern} signals to indicate footnote height}%
-\changes{4.1o}{2010/02/02}{(AO, 576) Allow \classname{lscape} to act on \cs{@outputbox} at the right time}%
-\changes{4.1p}{2010/02/24}{(AO, 583) Provide setup code also for footnotes in a one-column document}%
-\changes{4.2a}{2018/12/12}{(MD) Updated name of README file and use standard fonts when typesetting}%
-\changes{4.2d}{2020/09/19}{(PHO) Adapt \cs{document} and \cs{enddocument} hooks to the 2020-10-01 \LaTeX{} release.}%
-\changes{4.2d}{2020/09/30}{(PHO) Correct \cs{@normalcr} patch for \LaTeX{} 2020-02-02 and later.}%
-\end{filecontents*}
-%    \end{macrocode}
-%
-% \subsection{The Document Body}
-%
-% Here is the document body, containing only a
-% \cmd\DocInput\ directive---referring to this very file.
-% This very cute self-reference is a common \classname{ltxdoc} idiom.
-%    \begin{macrocode}
-\begin{document}%
-\def\revtex{REV\TeX}%
-\expandafter\DocInput\expandafter{\jobname.dtx}%
-\end{document}
-%</driver>
-%    \end{macrocode}
-%
-% \section{Using this package}
-% Once this package is installed on your filesystem, you can employ it in
-% adding functionality to \LaTeX\ by invoking it in your document or document class.
-%
-% \subsection{Invoking the package}
-% In your document, you can simply call it up in your preamble:
-% \begin{verbatim}
-%\documentclass{book}%
-%\usepackage{ltxgrid}%
-%\begin{document}
-%<your document here>
-%\end{document}
-% \end{verbatim}
-% However, the preferred way is to invoke this package from within your
-% customized document class:
-% \begin{verbatim}
-%\NeedsTeXFormat{LaTeX2e}[1995/12/01]%
-%\ProvidesClass{myclass}%
-%\LoadClass{book}%
-%\RequirePackage{ltxgrid}%
-%<class customization commands>
-%\endinput
-% \end{verbatim}
-%
-% Note that this package requires the features of the \classname{ltxutil} package,
-% available at
-% \url{publish.aps.org/revtex}.
-%
-% Once loaded, the package gives you acccess to certain procedures,
-% usually to be invoked by a \LaTeX\ command or environment, but not at the document level.
-% 
-% \subsection{Changing the page grid}%
-% This package provides two procedures, \cmd\onecolumngrid, \cmd\twocolumngrid,
-% that change the page grid (it can be extended to more columns and to other page grids).
-%
-% They differ from standard \LaTeX's \cmd\onecolumn\ and \cmd\twocolumn\ commands in that
-% they do not force a page break. Also, upon leaving a multiple-column grid, the columns are balanced.
-% In other respects they work same.
-%
-% They differ from the grid-changing commands of Frank Mittelbach's \classname{multicol} package
-% in that they allow floats of all types (single- and double column floats, that is) and
-% preserve compatability with the \classname{longtable} package.
-% 
-% These commands must be issued in vertical mode (conceivably via a \cmd\vadjust) such that
-% they are ultimately present in the MVL, where they can do their work.
-% Because they do not work in \LaTeX's left-right mode, they are unsuitable at the 
-% document level.
-% Furthermore, packaging a grid command in a \cmd\vadjust, although possible, will probably 
-% not acheive satisfactory page layout.
-%
-% Page grid commands are not intended to be issued unnecessarily: only the first of
-% two successive \cmd\onecolumngrid\ commands is effective; the second will be silently ignored.
-%
-% \DescribeMacro\onecolumngrid
-% You command \LaTeX\ to return to the one-column grid with the
-% \cmd\onecolumngrid\ command. If you are already in the one-column grid, this
-% is a no-op. The one-column grid is considered special of all page grids, in that
-% no portion of the page is held back (in \cmd\pagesofar); all items that might go
-% on the current page (with the exception of floats and footnotes) are on the MVL.
-%
-% \DescribeMacro\twocolumngrid
-% You command \LaTeX\ to return to the two-column grid with the
-% \cmd\twocolumngrid\ command. If you are already in the two-column grid, this
-% is a no-op.
-% 
-% These two commands should be issued by a macro procedure that can ensure that 
-% \TeX\ is in outer vertical mode. 
-% 
-% \subsection{Changing the MVL}%
-%
-% This package also provides commands to modify the main vertical list (MVL) in a safe way.
-% The scheme here is to structure, insofar possible, \TeX's MVL as follows:
-%\begin{quotation}
-%box or boxes\\
-%penalty\\
-%glue
-%\end{quotation}
-% This should be a familiar sequence. It is the prototype sequence for a vertical list,
-% and is followed when \TeX\ breaks paragraphs into lines, and when \TeX\ generates 
-% a display math equation.
-%
-% If you (as a macro programmer) wish to modify the value of the penalty or glue item, 
-% you can use one of the MVL-altering commands to do so. Certain operations are implemented
-% here; you can make up your own.
-% 
-% Note that these commands must be issued in vertical mode, perhaps via a \cmd\vadjust\ or a \cmd\noalign.
-% They can work directly if you are in inner mode (say within a parbox or a minipage).
-%
-% \DescribeMacro\removestuff
-% You instruct \LaTeX\ to remove both the penalty and the glue item with this command.
-%
-% \DescribeMacro\addstuff
-% You issue the \cmd\addstuff\arg{penalty}\arg{glue} command to add a penalty, glue, or both.
-% If you do not wish to add one or the other, the corresponding argument should be nil.
-% Note that the effect of \cmd\addstuff\ is to stack the penalties and glue items.
-% Therefore, the lesser of the two penalties takes effect,
-% and the two glue items add together. 
-%
-% \cmd\addstuff\ is limited because once applied, it cannot be applied again with correct results.
-%
-% \DescribeMacro\replacestuff
-% The \cmd\replacestuff\ command is syntactically the same as \cmd\addstuff, but works
-% differently: the existing penalty and glue are replaced or modified.
-%
-% The specified penalty is not inserted if the existing penalty is greater than 10000
-% (that is, in case of a \cmd\nobreak), otherwise, the lower (non-zero) of the two penalties is inserted.
-% 
-% If the specified glue has a larger natural component than the existing glue, we replace the glue.
-% However, if the specified glue's natural component is negative, then the existing glue's natural component is 
-% changed by that amount.
-%
-% \cmd\replacestuff\ can be applied mutiple times bceause it retains the list structure in the canonical form.
-%
-% Note that we treat two penalties specially (as does \TeX): a penalty of 10000 is considered 
-% a garbage value, to be replaced if found. This is the signal value that \TeX\ inserts on
-% the MVL replacing the penalty that caused the page break (if the page break occurred at a penalty).
-% Also, a penalty of zero is indistinguishable from no penalty at all, so it will always 
-% be replaced by the given value.
-%
-% Therefore, it is highly recommended to never set any of \TeX's penalty parameters to 
-% zero (a value of, say, 1, is practically the same), nor should a skip parameter be set to zero
-% (instead, use, say, 1sp). Also, to prevent a pagebreak, do not use a penalty of 10000, use, say
-% 10001 instead.
-%
-% You can define your own construct that modifies the MVL:
-% Define a command, say, \cmd\myadjust, as follows:
-%\begin{verbatim}
-%\def\myadjust#1{\noexpand\do@main@vlist{\noexpand\@myadjust{#1}}\@tempa}%
-%\end{verbatim}
-% that is, \cmd\myadjust\ invokes \cmd\do@main@vlist, passing it the procedure name
-% \cmd\@myadjust\ along with the arguments thereof pre-expanded.
-% Next,  define the procedure \cmd\@myadjust:
-%\begin{verbatim}
-%\def\@myadjust#1{<meddle with the MVL>}%
-%\end{verbatim}
-% when \cmd\@myadjust\ executes, you will be in the output routine (in inner vertical mode)
-% and the MVL will be that very vertical list.
-%
-%
-%
-%
-% \section{Compatability with \LaTeX's Required Packages}
-% Certain packages, usually ones written by members of the 
-% \LaTeX\ Project itself, have been designated ``required'' and
-% are distributed as part of standard \LaTeX.
-% These packages have been placed in a priviledged position
-% vis \'a vis the \LaTeX\ kernel in that they override the definitions of certain kernel macros.
-%
-% Compatability between \classname{ltxgrid} and these packages is complicated
-% by a number of factors. First is that \classname{ltxgrid} alters the meaning of some of the same
-% kernel macros as certain of the ``required'' packages.
-% Second is that fact that certain of the ``required'' packages of \LaTeX\ are incompatible with 
-% each other.
-%
-% Examples of the first kind are the \classname{ftnright}, \classname{multicol}, and \classname{longtable} 
-% packages.
-% The \classname{ltxgrid} package is not compatible with \classname{multicol},
-% but if you are using \classname{ltxgrid}, you do not need to use \classname{ftnright} or \classname{multicol}
-% anyway. The \classname{ltxgrid} package does however attempt to be compatible with \classname{longtable}.
-%
-% Among the ``required'' packages that are mutually incompatible are \classname{multicol} and \classname{longtable},
-% the incompatibility arising because both packages replace \LaTeX's output routine:
-% if one package is active, the other must not be so.
-% This state of affairs has remained essentially unchanged since the introduction of the two as \LaTeX2.09 packages in the late 1980s.
-%
-% The reason that \classname{ltxgrid} can remain compatible with \classname{longtable} is due to the
-% introduction of a more modern architecture, the ``output routine dispatcher'', which allows all macro packages access to the
-% safe processing environment of the output routine, on an equal footing.
-% The relevant portions of the \classname{longtable} package are reimplemented in \classname{ltxgrid}
-% to take advantage of this mechanism.
-%
-% Timing is critical:
-% the \classname{ltxgrid} package will be incompatible with any package that
-% redefines any of the kernel macros that \classname{ltxgrid} patches---if that
-% package is loaded \emph{after} \classname{ltxgrid}.
-%
-% Hereinafter follows some notes on specific \LaTeX\ packages.
-%
-% \subsection{ftnright}
-% Frank Mittelbach's \classname{ftnright} package effects a change to \LaTeX's
-% \cmd\twocolumn\ mode such that footnotes are set at the bottom of the right-hand
-% column instead of at the foot of each of the two columns.
-%
-% Note that it overwrites three \LaTeX\ kernel macros: \cmd\@outputdblcol, \cmd\@startcolumn, and \cmd\@makecolumn.
-% Fortunately none of the three are patched by \classname{ltxgrid}, so that compatability
-% is not excluded on this basis.
-%
-% At the same time, it changes the meaning of \cmd\footnotesize, the macro that is automatically 
-% invoked when setting a document's footnote into type.
-% One might well argue that it is an error for the meaning of \cmd\footnotesize\ to be determined by 
-% a package such as \classname{ftnright}, that indeed such a choice should be made in the 
-% document class, or in a file such as \file{bk10.clo}.
-%
-% To avoid being tripped up by this misfeature in \classname{ftnright}, it is only necessary to 
-% reassert our meaning for \cmd\footnotesize\ later on, after \classname{ftnright} has been loaded.
-%
-% Note that \classname{ftnright} inserts code that demands that \LaTeX's flag \cmd\if@twocolumn\
-% is true, that is, it will complain if deployed in a \cmd\onecolumn\ document.
-% It is therefore necessary for any other multicolumn package to assert that flag in order to
-% avoid this package's complaint. It is an interesting question exactly why this package has
-% this limitation. After all, a one-column page grid is just a degenerate case of the
-% two column.
-%
-% \subsection{longtable}
-% David Carlisle's \classname{longtable} package sets tables that can be so long as to break over pages.
-% According to its author, it uses the same override of \LaTeX's output routine as
-% Frank Mittelbach's \classname{multicol} package. By implication, then, it has a hard
-% incompatability with the latter.
-% 
-% The \classname{longtable} package also performs a check of whether the document is in 
-% \cmd\twocolumn\ mode, and declines to work if this is the case. It is not clear, however,
-% that there is any true incompatability present if so. It's just that David did not see any reason
-% anyone would want to set such long tables in a multicolumn document, hence the check.
-%
-% There does not appear to be any indication that \classname{longtable} would work less 
-% well under \classname{ltxgrid} than under standard \LaTeX's \cmd\twocolumn\ mode.
-% Therefore, this \classname{ltxgrid} patches \classname{longtable} (if loaded) so as to provide
-% compatability. In the course of which, \classname{longtable} becomes more robust
-% (\classname{longtable} has mumerous bugs and incompatabilities of long standing,
-% some of which are repaired by \classname{ltxgrid}).
-%
-% One problem remains, namely that, if a \env{longtable} environment breaks over columns
-% and thereby inserts its special headers and footers at that break, and those columms are then
-% balanced (due to a return to the one-column page grid), then those inserted rows
-% will remain, and may no longer fall at the column break. This will, of course look
-% wrong.
-%
-% The only way to fix this problem is to avoid doing column balancing in the way 
-% I have implemented here; such an enhancement to this package is possible.
-%
-% \subsection{multicol}
-% Frank Mittelbach's \classname{multicol} package provides a page grid with many columns,
-% albeit denies the placement of floats in individual columns.
-%
-% It establishes its own \cmd\output\ routine, which is the reason it runs afoul of 
-% the \classname{longtable} package. On the other hand, \classname{ltxgrid} specifically
-% allows for the case where a package installs its own \cmd\output\ routine, so 
-% there is no incompatability on that basis.
-%
-% Still, it is pointless to use \classname{multicol} if you are using \classname{ltxgrid},
-% since both packages provide multicolumn page layouts.
-% Therefore, \classname{multicol} is not supported by \classname{ltxgrid}.
-%
-% \subsection{ltxgrid}
-% It has been pointed out that one of the disadvantages of adopting the \classname{ltxgrid} package is that 
-% it does alter the \LaTeX\ kernel. 
-% Any package that itself alters the \LaTeX\ kernel may be incompatible with \classname{ltxgrid}, and new packages
-% (destined perhaps to become part of the successor to \LaTeXe) may break \classname{ltxgrid}.
-%
-% The consequence is that packages introduced in future, and future changes to \LaTeX\ may be incompatible 
-% with \classname{ltxgrid}. 
-% This is, of course, true.
-% The development plan for \classname{ltxgrid} is that when such packages and \LaTeX\ kernel changes come about,
-% the burden will be on \classname{ltxgrid} to change in a way that provides for continued compatability with
-% those packages and \LaTeX\ kernel changes.
-% 
-%
-% \section{How \classname{ltxgrid} places footnotes}
-%
-% In conventional multicolumn layouts, a footnote will appear at the bottom of the column in which it is called out. 
-% The \classname{ltxgrid} package implements this conventional layout choice by default.
-% However, other choices are possible (a la \classname{ftnright}, whose compatability with \classname{ltxgrid} has not been tested).
-%
-% One unusual feature of \classname{ltxgrid}'s default implementation must be mentioned, though,
-% namely the case in a two-column page grid, where a footnote is followed by a temporary change to the one-column page grid
-% (e.g., for a wide equation).
-% In such a case, the material above the wide material is split into two columns, and a footnote whose callout 
-% appears in the right-hand column will nonetheless be set at the base of the left column.
-%
-% This arrangement was chosen because it ensures that the footnotes at the bottom of any page will appear in 
-% numerical order. It can be argued that this choice is ``incorrect'', but be that as it may,
-% the \classname{ltxgrid} package does not foreclose on other arrangements for the footnotes.
-% The package can be adapted to accomodate any page design desired.
-%
-% \section{Limitations in \classname{ltxgrid}'s default column balancing method}%
-%
-% In a multicolumn page grid, when encountering a page that is not completely full,
-% it is customary to set the material in balanced columns (typically with the last column no longer than any of the others).
-% Such a case also crops up when temporarily interrupting the multicolumn grid to set material on the full width of the page:
-% the material on the page above the break is customarily set in balanced columns.
-%
-% An awkward case arises when we have already set one or more complete columns of type before encountering the need to 
-% balance columns. In this subset of cases, the default in \classname{ltxgrid} is to 
-% do an operation I call ``re-balancing'':
-% the material on the page so far is pasted back together into a single column, and new, balanced column breaks are
-% calculated.
-%
-% This scheme typically works fine, but it has a significant vulnerability:
-% any discardable items trimmed at the original column break are lost, never to be retrieved.
-% Consequently, after re-balancing, an element like, say, a section head can fail to have the correct amount of whitespace above.
-%
-% This problem is due to an unfortunate optimization in \TeX, wherein a certain class of nodes is trimmed from the 
-% top of main vertical list upon returning from the output routine:
-% any penalty, glue, or leader node falls in to this class of discardable nodes,
-% and trimming proceeds until a non-discardable node (such as a box, or rule) is encountered.
-% It gets better: a third class of nodes is transparent to this trimming process;
-% they are neither discarded nor do they halt the process of trimming:
-% mark nodes and all whatsits fall into this class of transparent nodes;
-% they are quietly passed over during trimming.
-%
-% An alternative approach for \TeX\ to take would have been, 
-% rather than discarding the node entirely, to simply \emph{mark} it as discarded.
-% (Implementors of extended \TeX, please note!)
-% Then, upon shipping out, such nodes would not make it into the DVI.
-% \TeX's optimization, driven by the small computer architectures current when it was developed,
-% does save mem, but at the cost of revisiting page breaks in a reliable way.
-%
-% FIXME: how to fix a column break in the above case? Widetext?
-%
-%\StopEventually{}
-%
-% \section{Implementation of package}
-%
-% Special acknowledgment: this package uses concepts pioneered
-% and first realized by William Baxter (mailto:web at superscript.com)
-% in his SuperScript line of commercial typesetting tools, and
-% which are used here with his permission. His thorough understanding
-% of \TeX's output routine underpins the entire \classname{ltxgrid}
-% package.
-%
-% \subsection{Beginning of the \file{ltxgrid} {\sc docstrip} module}
-% Requires the underpinnings of the \classname{ltxkrnext} package.
-%    \begin{macrocode}
-%<*package>
-\def\package@name{ltxgrid}%
-\expandafter\PackageInfo\expandafter{\package@name}{%
- Page grid for \protect\LaTeXe,
- by A. Ogawa (arthur_ogawa at sbcglobal.net)%
-}%
-\RequirePackage{ltxutil}%
-%</package>
-%    \end{macrocode}
-%
-% \subsection{Banner}%
-%    \begin{macrocode}
-%<*kernel>
-%    \end{macrocode}
-%
-% \subsection{Sundry}%
-% Here are assorted macro definitions.
-% \begin{macro}{\lineloop}
-% \begin{macro}{\linefoot}
-% The (document-level) command \cmd\lineloop\ sets numbered lines until the 
-% specified count is reached. 
-% The command \cmd\linefoot\ sets a single, automatically numbered line, but with a footnote (with the specified label);
-% it automatically increments the line counter.
-% These commands are typically used to construct test documents. 
-%
-% Because the counter is globally advanced and never reset, successive 
-% calls to \cmd\lineloop\ should have an argument ever larger.
-% The formatted output will have each line labeled with its ordinal number.
-%    \begin{macrocode}
-\newcounter{linecount}
-\def\loop@line#1#2{%
- \par
- \hb@xt@\hsize{%
-  \global\advance#1\@ne
-  \edef\@tempa{\@ifnum{100>#1}{0}{}\@ifnum{10>#1}{0}{}\number#1}%
-  \@tempa\edef\@tempa{\special{line:\@tempa}}\@tempa
-  \vrule depth2.5\p@#2\leaders\hrule\hfil
- }%
-}%
-\def\lineloop#1{%
- \loopwhile{\loop@line\c@linecount{}\@ifnum{#1>\c@linecount}}%
-}%
-\def\linefoot#1{%
- \loop@line\c@linecount{%
-  \footnote{%
-   #1\special{foot:#1}\vrule depth2.5\p@\leaders\hrule\hfill
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Mark Components}%
-%
-% Override LaTeX's mark macros to allow more components.
-%
-% We remain bound by the weakness of LaTeX's scheme in that
-% one cannot emulate the action of \TeX\ whereby
-% material with marks can be inserted in the middle of
-% a vertical list such that the marks are reliably calculated.
-% If we did that, \cmd\@themark\ would no longer be utilized.
-%
-% A more robust scheme involves placing all marks (component and value)
-% into a list (using global scoping, i.e., \cmd\gdef),
-% and using \cmd\@@mark to place an index on that list into the MVL.
-% Then, e.g., \cmd\@@botmark signifies the place where that list is to be cut,
-% and the \cmd\botmark\ of any component is
-% the value of the last element of the cut
-% list having the given component. The \cmd\firstmark\ and \cmd\topmark\
-% can likewise be defined relative to \cmd\@@firstmark\ and \cmd\@@topmark,
-% except in the latter case, we want the first following the cut instead of the last
-% preceding the cut.
-%
-% The limitation of this scheme is its demands upon \TeX's mem.
-% The list of marks would need to be trimmed back to, effectively,
-% \cmd\topmark\ at the beginning of every page.
-% 
-% This approach is not yet part of the extended LaTeX kernel.
-%
-% \begin{macro}{\@@mark}
-% \begin{macro}{\@@topmark}
-% \begin{macro}{\@@firstmark}
-% \begin{macro}{\@@botmark}
-% \begin{macro}{\@@splitfirstmark}
-% \begin{macro}{\@@splitbotmark}
-% Remember primitives under a new set of names.
-%    \begin{macrocode}
-\let\@@mark\mark
-\let\@@topmark\topmark
-\let\@@firstmark\firstmark
-\let\@@botmark\botmark
-\let\@@splitfirstmark\splitfirstmark
-\let\@@splitbotmark\splitbotmark
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \subsubsection{Procedures that expose the component data structure}%
-% This portion of the code exposes the internal representation of 
-% the mark components. If we wish to add more components, we will have to revise
-% these macro definitions:
-% \cmd\@themark,
-% \cmd\nul@mark,
-% \cmd\set@mark@netw@,
-% \cmd\set@marktw@,
-% \cmd\set@markthr@@,
-% \cmd\get@mark@@ne,
-% \cmd\get@mark@tw@,
-% \cmd\get@mark@thr@@,
-% \cmd\get@mark@f@ur.
-%
-% \begin{macro}{\@themark}
-%FIXME: is it safer to eliminate \cmd\@themark\ in favor of a message that evaluates \cmd\@@botmark?
-%
-% Note: these definitions expose the data structure of mark components.
-%    \begin{macrocode}
-\def\@themark{{}{}{}{}}%
-\def\nul@mark{{}{}{}{}\@@nul}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\set@mark@netw@}
-% \begin{macro}{\set@marktw@}
-% \begin{macro}{\set@markthr@@}
-% These procedures insert the new value of a particular mark component into the given argument.
-% They expose the data structure of mark components.
-% 
-%    \begin{macrocode}
-\def\set@mark@netw@#1#2#3#4#5#6#7{\gdef#1{{#6}{#7}{#4}{#5}}\do@mark}%
-\def\set@marktw@#1#2#3#4#5#6{\gdef#1{{#2}{#6}{#4}{#5}}\do@mark}%
-\def\set@markthr@@#1#2#3#4#5#6{\gdef#1{{#2}{#3}{#6}{#5}}\do@mark}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\get@mark@@ne}
-% \begin{macro}{\get@mark@tw@}
-% \begin{macro}{\get@mark@thr@@}
-% \begin{macro}{\get@mark@f@ur}
-% These procedures retreive the value of a particular mark component.
-% They expose the data structure of mark components.
-%    \begin{macrocode}
-\def\get@mark@@ne#1#2#3#4#5\@@nul{#1}%
-\def\get@mark@tw@#1#2#3#4#5\@@nul{#2}%
-\def\get@mark@thr@@#1#2#3#4#5\@@nul{#3}%
-\def\get@mark@f@ur#1#2#3#4#5\@@nul{#4}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsubsection{Procedures that do not expose the component data structure}%
-%
-% \begin{macro}{\mark@netw@}
-% \begin{macro}{\marktw@}
-% \begin{macro}{\markthr@@}
-% These procedures insert the new value of a particular mark component into \cmd\@themark,
-% then execute \cmd\do@mark. 
-% They constitute the implementation layer for mark components one, two, and three.
-% An analogous procedure for component four could be defined; call it \cmd\markf@ur.
-% 
-%    \begin{macrocode}
-\def\mark@netw@{\expandafter\set@mark@netw@\expandafter\@themark\@themark}%
-\def\marktw@{\expandafter\set@marktw@\expandafter\@themark\@themark}%
-\def\markthr@@{\expandafter\set@markthr@@\expandafter\@themark\@themark}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\do@mark}
-% \begin{macro}{\do@@mark}
-% Access procedures \cmd\mark (AKA \cmd\@@mark).
-% The \cmd\do@mark\ procedure is used when a mark is being put down into the MVL;
-% \cmd\do@@mark\ when this happens in the output routine.
-%    \begin{macrocode}
-\def\do@mark{\do@@mark\@themark\nobreak@mark}%
-\def\do@@mark#1{%
- \begingroup
-  \let@mark
-  \@@mark{#1}%
- \endgroup
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\let@mark}
-% \begin{macro}{\nobreak@mark}%
-% The procedure that makes \cmd\csname s robust within a mark.
-% Use \cmd\appdef\ and \cmd\robust@\ to extend the list.
-%    \begin{macrocode}
-\def\let@mark{%
- \let\protect\@unexpandable@protect
- \let\label\relax
- \let\index\relax
- \let\glossary\relax
-}%
-\def\nobreak@mark{%
- \@if@sw\if@nobreak\fi{\@ifvmode{\nobreak}{}}{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsubsection{Using mark components}%
-%
-% These procedures use the component mark mechanism to implement
-% a mark component that remembers the current environment (used in page makeup)
-% and the the two mark components left over from the original \LaTeX.
-% The fourth component is presently unused.
-%
-% \begin{macro}{\mark@envir}
-% The third mark component's access procedures.
-% The \cmd\mark@envir\ and \cmd\bot@envir\ commands are a good model of how to write 
-% access procedures for a new mark component.
-%    \begin{macrocode}
-\def\mark@envir{\markthr@@}%
-\def\bot@envir{%
- \expandafter\expandafter
- \expandafter\get@mark@thr@@
- \expandafter\@@botmark
-             \nul@mark
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\markboth}
-% \begin{macro}{\markright}
-% \begin{macro}{\leftmark}
-% \begin{macro}{\rightmark}
-% Set procedures for legacy components.
-%    \begin{macrocode}
-\def\markboth{\mark@netw@}%
-\def\markright{\marktw@}%
-%    \end{macrocode}
-%
-% Retrieval procedures for legacy mark components.
-% The procedure for retrieving the first component from \cmd\botmark\ 
-% and the second component from \cmd\firstmark have names in \LaTeX;
-% they are called, respectively, \cmd\leftmark\ and \cmd\rightmark.
-%
-% It is possible to retrieve the components of \cmd\topmark\
-% as well: use \cmd\saved@@topmark.
-%    \begin{macrocode}
-\def\leftmark{%
- \expandafter\expandafter
- \expandafter\get@mark@@ne
- \expandafter\saved@@botmark
-             \nul@mark
-}%
-\def\rightmark{%
- \expandafter\expandafter
- \expandafter\get@mark@tw@
- \expandafter\saved@@firstmark
-             \nul@mark
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-%
-% \subsection{Output Super-routine}%
-%
-% We want to change \LaTeX's output routine, but do not wish to remain vulnerable
-% to interference from such ``required'' packages as
-% \classname{multicol} (authored by Frank Mittelbach)
-% and \classname{longtable} (authored by David P. Carlisle), which 
-% swap in their own output routines when the respective package is active.
-%
-% The better mechanism, used here, is due to William Baxter (web at superscript.com),
-% who has allowed his several ideas to be used in this package.
-%
-% In what follows, we effectively wrap up the old \LaTeX\ output routine inside
-% a new, more flexible ``super routine''. When the output routine is called,
-% the ``super routine'' acts as a dispatcher. If the old routine is needed, it is called.
-%
-% If a package attempts to substitute in their own output routine, they will effectively
-% be modifying a token register by the name of \cmd\output.
-% The primitive \cmd\output\ is now known by a different name, which should no longer be
-% necessary to use.
-%
-% Usage note: to make a visit to the output routine employing the dispatcher, enter
-% with a value of \cmd\outputpenalty\ that corresponds to a macro. Defining as follows:
-%\begin{verbatim}
-%\@namedef{output@10000}{<your code here>}%
-%\end{verbatim}
-% by convention, your output routine should void out \cmd\box\cmd\@cclv.
-%
-% In rewriting \LaTeX's output dispatcher
-% in a much simpler form, we also avoid the sin of multiple \cmd\shipout s
-% within a single visit to the output routine.
-%
-% Conceptually, we divide visits to the output routine into two classes.
-% The first involves natural page breaks
-% (at a \cmd\newpage\ or when \cmd\pagetotal $>$ \cmd\pagegoal)
-% and usually resulting in \cmd\box\cmd\@cclv\ either being shipped out or
-% salted away (e.g., each column in a multicolumn layout).
-% We might call this class the ``natural output routines''; the \cmd\outputpenalty\
-% will never be less than $-10000$.
-% Furthermore, we ensure that \cmd\holdinginserts\ is cleared when 
-% calling such routines.
-%
-% The other class involves a forced visit to the output routine
-% via a large negative penalty ($< -10000$). They do not generally
-% result in a \cmd\shipout\ of \cmd\box\cmd\@cclv: they may be dead cycles.
-% We provide a mechanism (call it a ``one-off'' output routine) that allows
-% us to specify certain processing to be done when \TeX\ reaches
-% the current position on the page.
-%
-% One-off output routines themselves fall into two divisions, ones
-% that process \cmd\box\cmd\@cclv, and ones that work on the main vertical list (MVL).
-% The former are typified by changes to the page grid, perhaps
-% even column balancing.
-% The latter involve the insertion of penalties or glue and the processing of floats.
-% 
-% The natural output routine is a single procedure. We have not introduced multiple
-% natural output routines based on the \cmd\outputpenalty\ because \TeX\ does not
-% support such a thing: \TeX\ sometimes lays down a penalty whose value is the sum 
-% of other penalties. Because of this, we cannot depend on the value of \cmd\outputpenalty\
-% in such areas.
-%
-% We do introduce flexibility in the form of a mechanism for patching into the
-% natural output routine. Three hooks are offered, allowing a procedure
-% to prepare for the upcoming visit to the output routine,
-% access to \cmd\box\cmd\@cclv, and after doing \cmd\shipout\ (or otherwise 
-% committing the material to the page).
-%
-% Environments, commands, and even packages can install their
-% own procedures into these hooks.
-% For instance, if the longtable package is loaded, it will install
-% its procedures, but those procedures will punt if the page break 
-% being processed does not actually fall within a longtable environment.
-%
-% \begin{macro}{\primitive@output}
-% Here we remember the \TeX\ primitive \cmd\output\ and its value,
-% and then proceed to take over the \cmd\csname\ of \cmd\output,
-% making it a \cmd\toks\ register and installing the old value of
-% the output routine.
-%    \begin{macrocode}
-\let\primitive@output\output
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\output@latex}
-% \begin{macro}{\output}
-% Grab the tokens in \cmd\the\cmd\output\ (but without the extra set of braces).
-% The value of \cmd\toks@\ must remain untouched until loaded into the appropriate token 
-% register; this is done a few lines below.
-%    \begin{macrocode}
-\long\def\@tempa#1\@@nil{#1}%
-            \toks@
-\expandafter\expandafter
-\expandafter{%
-\expandafter \@tempa
-             \the\primitive@output
-             \@@nil
-             }%
-\newtoks\output@latex
-\output@latex\expandafter{\the\toks@}%
-\let\output\output@latex
-%    \end{macrocode}
-%
-% A comment on compatibility with other packages that co-opt the output routine.
-%
-% Somewhere on the LaTeX-L list, David Kastrup has urged macro  writers to take over 
-% the output routine in such a way that others can do likewise. How is this to be 
-% accomplished?
-%
-% Consider what the \classname{lineno} package does when it loads.
-% \begin{enumerate}
-% \item
-%  It does \cmd\let\ cmd\@tempa\ \cmd\output. 
-%  This has the effect of identifying \cmd\@tempa\ with the 
-%  \cmd\toks\ register we created above to hold the old output routine of \LaTeX.
-%  Let us say that was \cmd\toks14. 
-% \item
-%  \classname{lineno} itself effectively does \cmd\newtoks\ \cmd\@LN@output, 
-%  which assigns that \cmd\csname\ to \cmd\toks 15.
-% \item
-%  It loads \cmd\@LN@output\ with the contents of \cmd\@tempa 
-%  (that is, \cmd\toks14, our copy of \LaTeX's output routine).
-% \item
-%  Then it loads \cmd\@tempa\ with its own desired procedure, 
-%  to be executed at \cmd\output\ time, thereby taking over what it thinks is the output routine,
-%  but which is in reality the procedure \revtex\ executes when it wants to pass control
-%  to \LaTeX's original output routine.
-% \item
-%  It then does \cmd\let\ \cmd\output\ \cmd\@LN@output, 
-%  which now identifies \cmd\output\ with \cmd\toks15, the output routine of \classname{lineno}.
-% \item
-%  When the \cmd\output\ routine is triggered, 
-%  the primitive output routine \cmd\primitive@output\ is executed, and if 
-%  appropriate, control is passed to \cmd\output@latex, which \revtex\ had loaded with the old
-%  \LaTeX\ output routine, but which is presently loaded with that of \classname{lineno}.
-% \item
-%  The output routine of \classname{lineno} is executed, and if appropriate control is passed
-%  to \cmd\@LN@output, the old output routine of \LaTeX.
-% \item
-%  Furthermore, the \cmd\csname\ \cmd\output\ now points to \cmd\@LN@output\ (\cmd\toks15).
-%  This means that someone coming in after \classname{lineno} to take over the output routine
-%  will actually get executed after that of \classname{lineno}, but before \LaTeX.
-% \end{enumerate}
-% As you can see, the process of taking over the output routine may continue until all of the 
-% \cmd\toks\ registers have been allocated. 
-% If, say, \classname{newpackage} would itself like to take over the output routine,
-% and if it uses the above set of steps, then when the output routine is triggered, the order
-% of execution is \revtex, then \classname{lineno}, then \classname{newpackage}, then \LaTeX.
-% Each new package inserts itself on front of \LaTeX.
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\dispatch@output}
-% \changes{4.1b}{2008/08/04}{(AO, 456) Compatibility with other packages that override the output routine, following suggestion by David Kastrup.}
-% We now install our own output routine in place of the original 
-% output routine of \LaTeX, which is still available as \cmd\the\ \cmd\output.
-%
-% The output routine is simply the procedure \cmd\dispatch@output.
-% It either dispatches to a procedure based on a particular value of
-% \cmd\outputpenalty\ or it executes \cmd\the\cmd\output@latex\ tokens.
-%    \begin{macrocode}
-\primitive@output{\dispatch@output}%
-\def\dispatch@output{%
- \let\par\@@par
-%    \end{macrocode}
-% Try to interpret \cmd\outputpenalty\ as a dispatcher to a message handler, 
-% its value is, e.g., \cmd\do@startpage@pen.
-%    \begin{macrocode}
- \expandafter\let\expandafter\output@procedure\csname output@\the\outputpenalty\endcsname
-%    \end{macrocode}
-% If we have failed to find a dispatcher, then settle for \cmd\output@latex.
-%    \begin{macrocode}
- \@ifnotrelax\output@procedure{}{%
-  \expandafter\def\expandafter\output@procedure\expandafter{\the\output@latex}%
- }%
-%    \end{macrocode}
-% Now test if the dispatcher is the special case of \cmd\execute@message@pen, in which case execute the \cmd\@message@saved.
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
- \expandafter\@ifx\expandafter{\csname output@-\the\execute@message@pen\endcsname\output@procedure}{%
-  \let\output@procedure\@message@saved
- }{}%
- \ltxgrid@info@sw{\class@info{\string\dispatch@output}\say\output@procedure\saythe\holdinginserts}{}%
- \outputdebug@sw{\output@debug}{}%
- \output@procedure
-}%
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\def\set@output@procedure#1#2{%
- \count@\outputpenalty\advance\count@-#2%
- \expandafter\let\expandafter#1\csname output@\the\count@\endcsname
-}%
-%    \end{macrocode}
-%
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% The following procedure is executed at the beginning of each visit to the output routine, 
-% contingent on the level of diagnostics specified. 
-% However, it bails out when the visit is part of a tight sequence of visits to the output routine. 
-%    \begin{macrocode}
-\def\output@debug{%
- \def\@tempa{\save@message}%
- \@ifx{\output@procedure\@tempa}{%
-  \true@sw
- }{%
-  \@ifnum{\outputpenalty=-\save@column@insert@pen}{%
-   \@ifnum{\holdinginserts>\z@}%
-  }{%
-   \false@sw
-  }%
- }%
- {}{\output@debug@}%
-}%
-\def\output@debug@{%
-%<ignore> 	\saythe\inputlineno
- 	\saythe\outputpenalty
- 	\saythe\interlinepenalty
- 	\saythe\brokenpenalty
- 	\saythe\clubpenalty
- 	\saythe\widowpenalty
- 	\saythe\displaywidowpenalty
- 	\saythe\predisplaypenalty
- 	\saythe\interdisplaylinepenalty
- 	\saythe\postdisplaypenalty
- 	\saythe\badness
- 	\say\thepagegrid
- 	\saythe\pagegrid@col
- 	\saythe\pagegrid@cur
-%<ignore>  \say\bot@envir
- 	\saythe\insertpenalties
-%<ignore>  \say\@@topmark
-%<ignore>  \say\saved@@topmark
-%<ignore>  \say\@@firstmark
-%<ignore>  \say\saved@@firstmark
- 	\say\@@botmark
-%<ignore>  \say\saved@@botmark
- 	\saythe\pagegoal
- 	\saythe\pagetotal
- 	\saythe{\badness\@cclv}%
- 	\say\@toplist
- 	\say\@botlist
- 	\say\@dbltoplist
- 	\say\@deferlist
- 	\trace@scroll{%
- 		\showbox\@cclv
- 		\showbox\@cclv@saved
- 		\showbox\pagesofar
-%    \end{macrocode}
-% Klootch! The following line provides only for two-column page grid; if debugging more columns, you must
-% add more statements here. 
-%    \begin{macrocode}
- 		\showbox\csname col@1\endcsname
- 		\showbox\footsofar
- 		\showbox\footins
- 		\showbox\footins@saved
- 		\showlists
- 	}%
-}%
-\@ifxundefined{\outputdebug@sw}{%
- \@booleanfalse\outputdebug@sw
-}{}%
-\def\trace@scroll#1{\begingroup\showboxbreadth\maxdimen\showboxdepth\maxdimen\scrollmode#1\endgroup}%
-\def\trace@box#1{\trace@scroll{\showbox#1}}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@outputpage}
-% \begin{macro}{\@outputpage@head}
-% \begin{macro}{\@outputpage@tail}
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@tail} tailpatches \cs{@outputpage}}%
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@head} headpatches \cs{@outputpage}}%
-% The procedure \cmd\@outputpage\ of standard \LaTeX\ is the sole place where a \cmd\shipout\ is carried out.
-% The procedures that build \cmd\@outputbox\ just before a page is shipped out by \cmd\@outputpage\ are:
-% \cmd\@makecolumn,
-% \cmd\@combinepage, and
-% \cmd\@combinedblfloats.
-%
-% We need to head- and tailpatch this procedure, so we perform here
-% the only modifications to that procedure that are essential.
-% Elsewhere, we will build up the meanings of \cmd\@outputpage@head\ and \cmd\@outputpage@tail.
-%    \begin{macrocode}
-\prepdef\@outputpage{\@outputpage@head}%
-\let\@outputpage@head\@empty
-\appdef\@outputpage{\@outputpage@tail}%
-\let\@outputpage@tail\@empty
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\show@box@size}
-% \begin{macro}{\show@text@box@size}
-% \begin{macro}{\show@pagesofar@size}
-% \begin{macro}{\show@box@size@sw}
-% \begin{macro}{\total@text}
-% \changes{4.1b}{2008/08/04}{(AO, 452) Support length checking: show size of shipped out text.}
-% Procedure \cmd\show@box@size\ is a diagnostic for the sizes of boxes;
-% the boolean \cmd\show@box@size@sw\ turns it on and off.
-%    \begin{macrocode}
-\def\show@box@size#1#2{%
- \show@box@size@sw{%
-  \begingroup
-   \setbox\z@\vbox{\unvcopy#2\hrule}%
-   \class@info{Show box size: #1^^J%
-    (\the\ht\z@\space X \the\wd\z@) 
-    \the\c@page\space\space\the\pagegrid@cur\space\the\pagegrid@col
-   }%
-  \endgroup
- }{}%
-}%
-%    \end{macrocode}
-% Procedure \cmd\show@text@box@size\ tallies the size of the indicated column.
-% If \cmd\box\ \cmd\pagesofar\ is a factor, then its height has been memorized
-% in the depth of the tally box.
-% 
-% \changes{4.1f}{2009/07/10}{(AO, 518) Tally register overflow when locument is long}
-%    \begin{macrocode}
-\def\show@text@box@size{%
- \show@box@size{Text column}\@outputbox
- \tally@box@size@sw{%
-  \@ifdim{\wd\@outputbox>\z@}{%
-   \dimen@\ht\@outputbox\divide\dimen@\@twopowerfourteen
-   \advance\dimen@-\dp\csname box@size@\the\pagegrid@col\endcsname
-   \@ifdim{\dimen@>\z@}{%
-    \advance\dimen@ \ht\csname box@size@\the\pagegrid@col\endcsname
-    \global\ht\csname box@size@\the\pagegrid@col\endcsname\dimen@
-    \show@box@size@sw{%
-     \class@info{Column: \the\dimen@}%
-    }{}%
-   }{}%
-  }{}%
-  \global\dp\csname box@size@\the\pagegrid@col\endcsname\z@
- }{}%
-}%
-%    \end{macrocode}
-% Take the height of \cmd\box\ \cmd\pagesofar\ into account.
-%    \begin{macrocode}
-\def\show@pagesofar@size{%
- \show@box@size{Page so far}\pagesofar
- \dimen@\ht\pagesofar\divide\dimen@\@twopowerfourteen
- \global\dp\csname box@size@1\endcsname\dimen@
- \show@box@size@sw{%
-  \class@info{Pagesofar: \the\dimen@}%
- }{}%
-}%
-\@booleanfalse\tally@box@size@sw
-\@booleanfalse\show@box@size@sw
-\expandafter\newbox\csname box@size@1\endcsname
-\expandafter\setbox\csname box@size@1\endcsname\hbox{}%
-\expandafter\newbox\csname box@size@2\endcsname
-\expandafter\setbox\csname box@size@2\endcsname\hbox{}%
-\def\total@text{%
- \@tempdima\the\ht\csname box@size@2\endcsname\divide\@tempdima\@twopowertwo\@tempcnta\@tempdima
- \@tempdimb\the\ht\csname box@size@1\endcsname\divide\@tempdimb\@twopowertwo\@tempcntb\@tempdimb
- \class@info{Total text: Column(\the\@tempcnta pt), Page(\the\@tempcntb pt)}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Further thoughts about inserts}
-%
-% The only safe way to deal with inserts is to either set \cmd\holdininserts\ or
-% to commit to using whatever insert comes your way: you cannot change your mind
-% once you see a non-void \cmd\box\cmd\footins, say.
-%
-% Therefore all output routine processing must proceed with \cmd\holdinginserts\ set
-% until you are sure of the material to be committed to the page. At that point, you
-% can clear \cmd\holdinginserts, spew \cmd\box\cmd\@cclv, put down the appropriate penalty, 
-% and exit, with the knowledge that \TeX\ will re-find the same pagebreak, this time 
-% visiting the output routine with everything, including inserts, in their proper 
-% place.
-% This technique applies to split elements (screens, longtable, index) as well as to 
-% manufactured pages (float pages and clearpage pages). 
-%
-% Therefore, the output routine must not make assumptions about whether \cmd\holdinginserts\
-% should be cleared; instead this must be left to the one-off output routines or the natural output routine.
-%
-% If we are manufacturing pages (``float page processing''), and if \cmd\pagegoal\ is not equal to
-% \cmd\vsize, then inserts are at hand, and our criterion should take into account the insert
-% material, even though we cannot measure its height based on the size of \cmd\box\cmd\footins\
-% (because \cmd\holdinginserts\ is set, you see).
-%
-% It would be better to take the complement of \cmd\floatpagefraction\ and use that
-% as a standard for the looseness of the page. Since \cmd\pagegoal\ reflects the inserted material,
-% the criterion becomes the difference of the aggregate height of the floats and the \cmd\pagegoal\
-% versus this "page looseness" standard.
-%
-% As a check, consider what happens if we bail out: \cmd\@deferlist\ has never been touched, so it 
-% requires no attention. Also, \cmd\holdinginserts\ has never been cleared, so inserts require
-% no attention. So we only have to ensure that marks are preserved, which is already taken
-% care of by the message handler mechanism.
-%
-% If we are doing ordinary page cutting, then the scheme would be to detect whether we are within
-% a screen (or longtable as may be), do the adjustment to the page height, and return, but this time
-% with \cmd\holdinginserts\ cleared. Upon reentering the output routine, we may or may not be within
-% the screen environment, but we are now sure to have a final page break, and we can commit this
-% material (by shipping out or by saving it out as a full column).
-%
-% In the above, the first of the two visits to the output routine is a dead cycle and requires
-% propagation of marks, but nothing else.
-%
-% \subsection{The difference between inserts and floats}
-%
-% While revisiting this package in 2008, I needed to clarify under what circumstances inserts
-% would be added to the \cmd\pagesofar. My conclusion is that I had been treating them
-% exactly the same as floats, but that was a mistake. 
-%
-% Floats can be committed at the top of a column, in the middle, or at the bottom. 
-% Footnotes (the only \cmd\insert\ that is used in \LaTeX) may only be committed at the bottom
-% of a column. So, it was necessary to provide two versions of \cmd\@combinepage, one 
-% that committed \cmd\insert s, and the other that did not, the former used only when 
-% a column of text was committed. Note that even after a column is committed, we could change our minds:
-% for instance if in multicolumn grid and we decide to balance the columns. 
-%
-%
-% \subsection{The natural output routine}
-%
-% Here is the portion of the output routine that fields cases not handled by
-% the dispatcher. 
-%
-% The default is to ship out a page and then look around for more material
-% that might constitute a ``float page''. However, because \cmd\holdinginserts\
-% is normally set, this output routine must first have a dead cycle and
-% come back again with \cmd\holdinginserts\ cleared.
-% Then, after shipping out, it puts down a message that 
-% will manufacture zero or more float pages, finally terminating
-% with a procedure that commits floats to a new unfinished page.
-%
-% To accomodate special processing, we execute hooks whose name is based
-% on the value of the "envir" mark component. The default is "document",
-% ensured by an initial mark of that value; the associated procedures
-% are all nil. Any unknown envir value will "\cmd\relax\ out".
-%
-% The test made by \cmd\toggle@insert\ tells whether we are on our first visit to
-% the output routine (with \cmd\holdinginserts\ still positive), or our second
-% (with \cmd\holdinginserts\ zeroed). The output routine will toggle the setting. 
-%
-% The commands \cmd\hold@insertions\ and \cmd\move@insertions\ respectively
-% clear and set \cmd\holdinginserts, so this procedure effectively
-% clears \cmd\holdinginserts\ just long enough to pick up the insertions.
-% Important: any output routine that clears \cmd\holdinginserts\
-% must guarentee that it is restored on the subsequent visit to the output routine.
-% Or, to put it another way, if an output routine detects that \cmd\holdinginserts\ 
-% is cleared, it should take it upon itself to restore it to a positive value before exiting.
-%
-% The branch with \cmd\holdinginserts\ set is executed first; the other
-% branch follows on practically immediately thereafter. In the first branch,
-% we simply execute the appropriate hook and then execute a dead cycle.
-%
-% In the branch with \cmd\holdinginserts\ cleared, the procedure
-% builds up the current column, which is now complete, with \cmd\@makecolumn, then
-% dispatches to the shipout routine associated with the current page grid, \cmd\output@column@.
-% At the end, it triggers the execution of an output routine to prepare the next column (or page).
-%
-% \subsection{Natural output routine}%
-%
-% \begin{macro}{\natural@output}
-% \begin{macro}{\output}
-% Here is the output routine that handles natural pagebreaks:
-% we now have page that needs to be shipped out or a portion of a page that is ready to be committed to the page grid.
-% Processing is of necessity divided into phases, \cmd\output@holding\ is executed upon first encountering the natural page-breaking point, while inserts are being held.
-% The second phase, \cmd\output@moving, is set in motion by the first: here the same material (in most cases) will be processed with \cmd\holdinginserts\ cleared,
-% and the insertions (e.g., footnotes) are split off into their assigned box registers. 
-%    \begin{macrocode}
-\def\natural@output{\toggle@insert{\output@holding}{\output@moving}}%
-\output@latex{\natural@output}%
-%    \end{macrocode}
-%
-% In accordance with the scheme suggested by David Kastrup for allowing another output routine
-% to slip itself into ours, we use a token register called \cmd\output. 
-% However, we reserve the ability to restore things if we so desire.
-% This we must do in the case of the \filename{lineno.sty} package, because its functionality
-% is best served by being integrated into our own dispatcher-based output routine.
-%
-% To restore our own output routine, we can repeat the above assignment,
-% \begin{verbatim}
-%\output@latex{\natural@output}%
-% \end{verbatim}
-% some time before the document begins.
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\output@holding}
-% \begin{macro}{\@if@exceed@pagegoal}
-% The procedure \cmd\output@holding\
-% is our first cycle through the output routine; \cmd\holdinginserts\ is still set.
-% We give the current environment a heads up
-% (it is through this means that \classname{longtable} sets its running header and footer),
-% then we execute a dead cycle, which should propagate marks. 
-%
-% One corner case that can crop up is the presence of a single unbreakable chunk whose size is larger
-% than \cmd\vsize.
-% Doing a dead cycle under such circumstances will not find the same breakpoint as this time
-% (remember we threw in a \cmd\mark\ node).
-% Instead, we attempt to remove the excess height of the material, so we can continue to propagate marks.
-%
-% The corner case is at hand if the natural size of \cmd\box\cmd\@cclv\ exceeds \cmd\pagegoal\ and
-% the contents cannot be shrunk to fit.
-%
-% \changes{4.1b}{2008/08/04}{New procedure for showing a box contents, \cs{trace@box}}
-%    \begin{macrocode}
-\def\output@holding{%
- \csname output@init@\bot@envir\endcsname
- \@if@exceed@pagegoal{\unvcopy\@cclv}{%
-  \setbox\z@\vbox{\unvcopy\@cclv}%
-  \outputdebug@sw{\trace@box\z@}{}%
-  \dimen@\ht\@cclv\advance\dimen@-\ht\z@
-  \dead@cycle@repair\dimen@
- }{%
-  \dead@cycle
- }%
-}%
-\def\@if@exceed@pagegoal#1{%
- \begingroup
-  \setbox\z@\vbox{#1}%
-  \dimen@\ht\z@\advance\dimen@\dp\z@
-  \outputdebug@sw{\saythe\dimen@}{}%
-  \@ifdim{\dimen@>\pagegoal}{%
-   \setbox\z@\vbox{\@@mark{}\unvbox\z@}%
-   \splittopskip\topskip
-   \splitmaxdepth\maxdepth
-   \vbadness\@M
-   \vfuzz\maxdimen
-   \setbox\tw@\vsplit\z@ to\pagegoal
-   \outputdebug@sw{\trace@scroll{\showbox\tw@\showbox\z@}}{}%
-   \setbox\tw@\vbox{\unvbox\tw@}%
-   \@ifdim{\ht\tw@=\z@}{%
-    \ltxgrid@info{Found overly large chunk while preparing to move insertions. Attempting repairs}%
-    \aftergroup\true@sw
-   }{%
-    \aftergroup\false@sw
-   }%
- }{%
-  \aftergroup\false@sw
- }%
- \endgroup
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\output@moving}
-% \begin{macro}{\@cclv@nontrivial@sw}
-% The procedure \cmd\output@moving\ 
-% is our second cycle through the output routine; \cmd\holdinginserts\ is now cleared,
-% and \cmd\insert s will have been split off into their respective box registers, like \cmd\footins.
-%
-% \begin{enumerate}
-% \item
-%  Set the values of \cmd\topmark\ and \cmd\firstmark.
-% \item
-%  If we got here because of a \cmd\clearpage\ command, remove the protection box that this mechanism has left on the MVL.
-% \item
-%  If the contents of \cmd\box\cmd\@cclv\ are non-trivial, commit it to the current page (as a column) or ship it out, as the case may call for.
-% \item
-%  If not, discard it (we are at the end of \cmd\clearpage\ processing).
-% \item
-%  Set various values, including the available space for setting type on the next column (\cmd\@colroom).
-% \end{enumerate}
-%
-% The processing for a non-trivial \cmd\box\cmd\@cclv\ are:
-% \begin{enumerate}
-% \item
-%  Execute the head procedure for the current environment.
-% \item
-%  Make up a column and ship it out (or commit it to the current page) via a procedure keyed to the current page grid.
-% \item
-%  Put down an interrupt for \cmd\do@startcolumn@pen: this will force a visit to the output routine for the 
-%  purpose of committing floats to the next column.
-% \item
-%  Possibly put down an interrupt to continue \cmd\clearpage\ proccessing.
-% \item
-%  Execute the tail procedure for the current environment.
-% \end{enumerate}
-%
-%
-% The processing for a trivial \cmd\box\cmd\@cclv\ are:
-% \begin{enumerate}
-% \item
-%  Void out \cmd\box\cmd\@cclv\ and give appropriate warning messages and diagnostics.
-% \item
-%  Put down the same interrupts as for the non-trivial case above.
-% \end{enumerate}
-%
-% This instance of \cmd\@makecolumn\ is followed by \cmd\output@column@, 
-% that is, it builds a column for \cmd\shipout\ rather than for adding to \cmd\pagesofar. 
-%
-% We need to handle cases where the \cmd\output@pre@, \cmd\output@column@, or \cmd\output@post@\
-% dispatchers come up \cmd\relax ed out: the default is to execute the corresponding 
-% procedures from the \env{docuemnt} environment and the one-column grid respectively.
-%
-% One such case comes up with frequency: at the end of the document, where the \cmd\botmark\ is
-% now empty.
-% \changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-% \changes{4.1n}{2010/01/02}{(AO, 571) Use procedures \cs{output@do@prep} and \cs{output@column@do} as dispatchers}
-%    \begin{macrocode}
-\def\output@moving{%
- \set@top@firstmark
- \@ifnum{\outputpenalty=\do@newpage@pen}{%
-  \setbox\@cclv\vbox{%
-   \unvbox\@cclv
-   \remove@lastbox
-   \@ifdim{\ht\z@=\ht\@protection@box}{\box\lastbox}{\unskip}%
-  }%
- }{}%
- \@cclv@nontrivial@sw{%
-  \expandafter\output@do@prep\csname output@prep@\bot@envir \endcsname
-  \@makecolumn\true@sw
-  \expandafter\output@column@do\csname output@column@\thepagegrid\endcsname
-  \protect@penalty\do@startcolumn@pen
-  \clearpage@sw{%
-   \protect@penalty\do@endpage@pen
-  }{}%
-  \expandafter\let\expandafter\output@post@\csname output@post@\bot@envir \endcsname
-  \outputdebug@sw{\say\output@post@}{}%
-  \@ifx{\output@post@\relax}{\output@post@document}{\output@post@}%
- }{%
-  \void@cclv
- }%
- \set@colht
- \global\@mparbottom\z@
- \global\@textfloatsheight\z@
-}%
-%    \end{macrocode}
-% Procedure \cmd\output@do@prep\ dispatches to the proper procedure to prepare page.
-%    \begin{macrocode}
-\def\output@do@prep#1{%
- \outputdebug@sw{\class@info{Prep: \string#1}}{}%
- \@ifx{#1\relax}{\output@prep@document}{#1}%
-}%
-%    \end{macrocode}
-% Procedure \cmd\output@column@do\ dispatches to the proper procedure to output column or page.
-%    \begin{macrocode}
-\def\output@column@do#1{%
-  \outputdebug@sw{\class@info{Output column: \string#1}}{}%
-  \@ifx{#1\relax}{\output@column@one}{#1}%
-}%
-\def\void@cclv{\begingroup\setbox\z@\box\@cclv\endgroup}%
-\def\remove@lastbox{\setbox\z@\lastbox}%
-%    \end{macrocode}
-%
-% The procedure \cmd\@cclv@nontrivial@sw\ determines if this visit to \cmd\output@moving\
-% is a trivial one, which happens at the end of \cmd\clearpage\ processing and under some pathological circumstances.
-% It emits a Boolean, so it is syntactically like \cmd\true@sw, albeit does not execute solely via expansion.
-%
-% Note: the case where \cmd\box\cmd\@cclv\ is void comes up at the very beginning of the job, when 
-% typesetting a (full-page-width) title block in a two-column layout.
-%
-% Note: the code that removes the last box and skip from the output is intended to detect the case
-% where the output has whatsit nodes followed by topskip and a protection box.
-% This is what happens under normal circumstances at the end of \cmd\clearpage\ processing.
-% \changes{4.1b}{2008/08/04}{New procedure for showing a box contents, \cs{trace@box}}
-%    \begin{macrocode}
-\def\@cclv@nontrivial@sw{%
- \@ifx@empty\@toplist{%
-  \@ifx@empty\@botlist{%
-   \@ifvoid\footins{%
-    \@ifvoid\@cclv{%
-     \false@sw
-    }{%
-     \setbox\z@\vbox{\unvcopy\@cclv}%
-     \@ifdim{\ht\z@=\topskip}{%
-      \setbox\z@\vbox\bgroup
-       \unvbox\z@
-       \remove@lastbox
-       \dimen@\lastskip\unskip
-       \@ifdim{\ht\z@=\ht\@protection@box}{%
-        \advance\dimen@\ht\z@
-        \@ifdim{\dimen@=\topskip}{%
-         \aftergroup\true@sw
-        }{%
-         \aftergroup\false@sw
-        }%
-       }{%
-        \aftergroup\false@sw
-       }%
-%    \end{macrocode}
-% End of \cmd\box\cmd\z@.
-%    \begin{macrocode}
-      \egroup
-      {%
-%    \end{macrocode}
-% Normal for \clearpage
-%    \begin{macrocode}
-       \false@sw
-      }{%
-       \true@sw
-      }%
-     }{%
-      \@ifdim{\ht\z@=\z@}{%
-       \ltxgrid@info{Found trivial column. Discarding it}%
-       \outputdebug@sw{\trace@box\@cclv}{}%
-       \false@sw
-      }{%
-       \true@sw
-      }%
-     }%
-    }%
-   }{%
-    \true@sw
-   }%
-  }{%
-   \true@sw
-  }%
- }{%
-  \true@sw
- }%
-}%
-%    \end{macrocode}
-%
-% 
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\protect@penalty}
-% The procedure \cmd\protect@penalty\ is the utility procedure for invoking a 
-% one-off output routine. Such a routine can expect to find the protection box
-% above it in \cmd\box\cmd\@cclv: it should remove that box.
-%
-% Note that \cmd\execute@message\ does the same thing as \cmd\protect@penalty, but
-% in a slightly different way.
-%
-% We create a specially formulated box that will be universally used when a protection box is needed.
-% In this way, we can always recognize when \cmd\box\cmd\@cclv\ is trivial:
-% it will consist of whatsits followed by \cmd\topskip\ glue and the \cmd\@protection@box.
-%    \begin{macrocode}
-\def\protect@penalty#1{\protection@box\penalty-#1\relax}%
-\newbox\@protection@box
-\setbox\@protection@box\vbox to1986sp{\vfil}%
-\def\protection@box{\nointerlineskip\copy\@protection@box}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\dead@cycle}
-% \begin{macro}{\dead@cycle@repair}
-% The procedure \cmd\dead@cycle\ is defined separately as a utility which can be used by
-% any output processing routine to emulate what takes place in the standard output routine.
-%
-% Here, we have entered the output routine with \cmd\holdinginserts\ enabled, which means that we 
-% are not yet ready to ship out material, because the \cmd\insert\ registers are being held.
-% We want to clear \cmd\holdinginserts\ and come back here with the same page break as before, whereupon
-% we may properly proceed with page makeup.
-%
-% To do this, we
-% propagate marks, then spew the contents of \cmd\box\cmd\@cclv\ followed by the 
-% original output penalty that landed us here (but only if it is not 10000,
-% the flag value for a pagebreak not at a penalty).
-%
-% However, the natural output routine should do this only if \cmd\box\cmd\@cclv\ is nontrivial.
-% A pathological case exists wherein a box of height greater than \cmd\textheight\ would cause an infinite loop involving the output routine.
-% The procedure \cmd\dead@cycle@repair, attempts to catch this case and avoid the loop.
-%
-% The test of the height of \cmd\box\cmd\@cclv\ is not the correct one, because this test will run afoul in
-% the case where \cmd\box\cmd\@cclv\ contains nothing but an \cmd\insert\ node. What to do?
-%
-% It is possible that the pathological case can be detected by looking at \cmd\pagetotal. If that quantity is
-% zero, then \cmd\box\cmd\@cclv\ really is trivial.
-%
-% In the procedure \cmd\dead@cycle@repair, if \cmd\box\cmd\@cclv\ is nontrivial, we execute \cmd\dead@cycle,
-% otherwise it contains nothing but a mark, so we dispense with propagating marks
-% and we simply spew out \cmd\box\cmd\@cclv\ without an accompanying mark.
-% This has the effect of failing to propagate marks, but this problem is preferrable to the infinite loop,
-% which in principle could crash even a robust operating system by filling up the file system.
-%
-% If a document has such a large chunk, it should be fixed, so we give a message in the log.
-%
-% You ask, ``In what way does this infinite loop come about?'' Good question!
-%
-% The setup is a chunk in the MVL that is taller than \cmd\textheight. 
-% (Yes, it's that simple.)
-% As soon as the previous page ships out, the MVL will contain a mark (propagated from the previous page) followed
-% by that large chunk (call it the `big bad box', albeit does not need to be a single box).
-% The next visit to the output routine will be a natural page break, but
-% \TeX\ will select the juncture between the mark and the big bad box as the least-cost page break.
-% Unless the test in \cmd\dead@cycle\ is done, the cycle is perpetuated when the macro 
-% reinserts the mark.
-%
-% The crux matter is achieving, in a robust way, the goal of going from a \cmd\holdinginserts\ state to one
-% where the insertions are moving.
-%
-%    \begin{macrocode}
-\def\dead@cycle@repair#1{%
- \expandafter\do@@mark
- \expandafter{%
-              \@@botmark
-             }%
- \unvbox\@cclv
- \nointerlineskip
- \vbox to#1{\vss}%
- \@ifnum{\outputpenalty<\@M}{\penalty\outputpenalty}{}%
-}%
-\def\dead@cycle@repair@protected#1{%
- \expandafter\do@@mark
- \expandafter{%
-              \@@botmark
-             }%
- \begingroup
-  \unvbox\@cclv
-%    \end{macrocode}
-% Remove the protection box
-%    \begin{macrocode}
-  \remove@lastbox
-  \nointerlineskip
-  \advance#1-\ht\@protection@box
-  \vbox to#1{\vss}%
-  \protection@box % Reinsert protection box
-  \@ifnum{\outputpenalty<\@M}{\penalty\outputpenalty}{}%
- \endgroup
-}%
-\def\dead@cycle{%
- \expandafter\do@@mark
- \expandafter{%
-              \@@botmark
-             }%
- \unvbox\@cclv
- \@ifnum{\outputpenalty<\@M}{\penalty\outputpenalty}{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\output@init@document}
-% \begin{macro}{\output@prep@document}
-% \begin{macro}{\output@post@document}
-% The default processing simply provides for insertion of held-over footnotes.
-% At a natural page break, we are either at the bottom of a column or at the bottom 
-% of a page. In either case, the \cmd\output@init@\ processing adjusts for the height
-% of the held-over footnotes and bails out.
-% Upon our return, at \cmd\output@prep@\ time, the page break will accomodate the material;
-% it is now actually inserted by concatenating it with the contents of \cmd\footins.
-% The default processing for \cmd\output@post@\ is nil.
-% \changes{4.1b}{2008/08/04}{Box \cs{footbox} changed to box \cs{footsofar}}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\output@init@document{%
- \ltxgrid@info@sw{\class@info{\string\output@init@document}}{}%
- \global\vsize\vsize
-}%
-%    \end{macrocode}
-% QUERY: the following procedure is very like \cmd\combine@foot@inserts. Should it be the same?
-% Answer: no, the two differ: this procedure makes a local assignment of \cmd\footins;
-% the latter makes a global assignment of \cmd\footsofar.
-%
-% Note: In a multicolumn document, footnotes must \emph{not} be balanced at this point.
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\output@prep@document{%
- \ltxgrid@foot@info@sw{\class@info{\string\output@prep@document}\trace@scroll{\showbox\footins\showbox\footsofar}}{}%
- \@ifvoid\footsofar{%
- }{%
-  \global\setbox\footins\vbox\bgroup
-   \unvbox\footsofar
-   \@ifvoid\footins{}{%
-    \marry@baselines
-    \unvbox\footins
-   }%
-  \egroup
-  \ltxgrid@foot@info@sw{\trace@box\footins}{}%
- }%
-}%
-\def\output@post@document{}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@opcol}
-% The standard \LaTeX\ procedure \cmd\@opcol\ is now completely obsoleted.
-%    \begin{macrocode}
-\let\@opcol\@undefined
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@makecolumn}
-% \changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-% The procedure \cmd\@makecolumn\ packages up a page along with all its insertions and floats.
-% Therefore it is essential that it be executed with \cmd\holdininserts\ cleared.
-%
-% Note that there is a corner case when in a multi-column grid, where the change back to 
-% one-column grid occurs just after a complete page ships out. We want to detect when
-% \cmd\@cclv\ contains nothing but a \cmd\mark, but this is a \TeX\ impossibility.
-%
-% Note on \cmd\@kludgeins: we have removed this mechanism from \LaTeX, because the implementation 
-% of \cmd\enlargethispage\ no longer requires it. 
-% Here, for consistency sake, we remove \cmd\@makespecialcolbox.
-% 
-% The argument of \cmd\@makecolumn\ is a Boolean and determines if we combine the footnote material
-% into the present column. If the procedure is building a column for shipping out, then we will
-% combine the footnote material, if not, we return with the \cmd\footins\ box unchanged.
-%
-% \changes{4.1f}{2009/07/14}{(AO, 519) \cs{footins} content must be preserved and reintegrated}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-% \changes{4.1n}{2010/01/02}{(AO, 571) change calling sequence of \cs{combine@foot@inserts} to expose box registers}%
-% I changed the behavior of this procedure in the case where the argument is \cmd\false@sw:
-% send the unused footnote material to \cmd\footsofar.
-%    \begin{macrocode}
-\def\@makecolumn#1{%
- \ltxgrid@foot@info@sw{\class@info{\string\@makecolumn\string#1}}{}%
- \setbox\@outputbox\vbox\bgroup
-  \boxmaxdepth\@maxdepth
-  \@tempdima\dp\@cclv
-  \unvbox\@cclv
-  \vskip-\@tempdima
- \egroup
- \xdef\@freelist{\@freelist\@midlist}\global\let\@midlist\@empty
- \show@text@box@size
- \@combinefloats
- #1{%
-  \@combineinserts\@outputbox\footins
- }{%
-  \combine@foot@inserts\footsofar\footins
- }%
- \set@adj@colht\dimen@
- \count@\vbadness
- \vbadness\@M
- \setbox\@outputbox\vbox to\dimen@\bgroup
-  \@texttop
-  \dimen@\dp\@outputbox
-  \unvbox\@outputbox
-  \vskip-\dimen@
-  \@textbottom
- \egroup
- \vbadness\count@
- \global\maxdepth\@maxdepth
-}%
-\let\@makespecialcolbox\@undefined
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@combineinserts}
-% The procedure to add the specified insertions to the packaged-up page. 
-% All other classes of insertions should also be dealt with at this time. 
-%
-% Note that the second argument must be a \cmd\newinsert\ register: we access the \cmd\box\ along with the \cmd\skip.
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-% \changes{4.1n}{2010/01/02}{(AO, 571) footnote rule is leaders, so that it may be removed by \cs{vsplit}; mechanism of \cs{kern} signals to indicate footnote height}%
-%    \begin{macrocode}
-\def\@combineinserts#1#2{%
- \ltxgrid@foot@info@sw{\class@info{\string\@combineinserts\string#1\string#2}\trace@box#2}{}%
- \setbox#1\vbox\bgroup
-  \unvbox#1%
-  \@ifvoid{#2}{}{%
-   \dimen@\ht#2\advance\dimen@\dp#2\advance\dimen@\skip#2%
-   \show@box@size{Combining inserts}#2%
-   \vskip\skip#2%
-%    \end{macrocode}
-% The footnote rule is created as leaders, so that it may be removed automatically (via \cmd\vsplit) 
-% in the event the footnote is recovered from this column. 
-% Note that if \cmd\color@begingroup\ or \cmd\normalcolor\ produce marks, this technique will be confounded. 
-%    \begin{macrocode}
-   \setbox\z@\vbox{\footnoterule}\dimen@i\ht\z@
-   \color@begingroup
-   \normalcolor
-   \cleaders\box\z@\vskip\dimen@i\kern-\dimen@i
-   \csname combine@insert@\the\pagegrid@col\endcsname#2%
-   \color@endgroup
-%    \end{macrocode}
-% The following tells \cmd\recover@column\ the size of the footnotes added here, including the skip glue above. 
-%    \begin{macrocode}
-   \kern-\dimen@\kern\dimen@
-  }%
- \egroup
- \ltxgrid@foot@info@sw{\trace@box#1}{}%
-}%
-%    \end{macrocode}
-% We provide for a layer of abstraction for the laying down of footnotes at the bottom of this column or page. 
-% \end{macro}
-%
-% \begin{macro}{\combine@insert@tw@}
-% \begin{macro}{\combine@insert@@ne}
-% \begin{macro}{\twocolumn@grid@setup}
-% \begin{macro}{\onecolumn@grid@setup}
-% \begin{macro}{\columngrid@setup}
-% \changes{4.1p}{2010/02/24}{(AO, 583) Provide setup code also for footnotes in a one-column document}%
-% The following two definitions cover the cases of a two-column document (with footnotes set on a single-column width),
-% and a one-column document.
-% However, the case of a two-column document with footnotes set on full text width is not covered. 
-% 
-% For a document in an overall two-column page grid, execute the commands
-% \cmd\twocolumn@grid@setup\ followed by \cmd\open@twocolumn;
-% if on the full page width (one-column grid), the command \cmd\onecolumn@grid@setup. 
-%
-% The following is the way REVTeX does the initialization.
-% The procedure \cmd\select@column@grid\ is executed at \cmd\AtBeginDocument\ time;
-% the boolean \cmd\twocolumn@sw\ selects between the two alternatives.
-% \begin{verbatim}
-%\def\select@column@grid{%
-% \twocolumn@sw{%
-%  \twocolumn@grid@setup
-%  \open@twocolumn
-% }{%
-%  \onecolumn@grid@setup
-% }%
-%}%
-%\appdef\class@documenthook{%
-% \select@column@grid
-%}%
-% \end{verbatim}
-%
-%    \begin{macrocode}
-\def\combine@insert@tw@#1{%
- \compose@footnotes@two#1\@ifvbox{#1}{\unvbox}{\box}#1%
-}%
-\def\combine@insert@@ne#1{%
- \compose@footnotes@one#1\@ifvbox{#1}{\unvbox}{\box}#1%
-}%
-\def\twocolumn@grid@setup{%
- \expandafter\let\csname combine@insert@1\endcsname\combine@insert@tw@
- \expandafter\let\csname combine@insert@2\endcsname\combine@insert@@ne
-}%
-\def\onecolumn@grid@setup{%
- \expandafter\let\csname combine@insert@1\endcsname\combine@insert@@ne
- \expandafter\let\csname combine@insert@2\endcsname\combine@insert@@ne
-}%
-\let\columngrid@setup\onecolumn@grid@setup
-\columngrid@setup
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@floatplacement}
-% In standard \LaTeX, someone (DPC?) makes the assumption that \cmd\@fpmin\ can be assigned
-% locally. This is no longer true now that we ship no more than one page per visit to the output routine.
-% We apply a bandaid.
-%    \begin{macrocode}
-\appdef\@floatplacement{%
- \global\@fpmin\@fpmin
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\pagebreak@pen}
-% While we are in the way of registering certain penalty values,
-% let us register the smallest one that will force a visit to the output routine. 
-% However, this penalty will not have an assciated macro: we wish to execute the 
-% natural output routine instead.
-%
-% Note that this penalty is invoked by \cmd\clearpage\ and \cmd\newpage.
-%    \begin{macrocode}
-\mathchardef\pagebreak@pen=\@M
-\expandafter\let\csname output@-\the\pagebreak@pen\endcsname\relax
-%    \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{Float placement}%
-%
-% \begin{macro}{\do@startcolumn@pen}
-% The procedure \cmd\do@startcolumn@pen\ is executed as a one-off output routine
-% just after a page is shipped out (or, in a multicolumn page grid, a column is salted away).
-%
-% Its job is to either generate a ``float page'' (in reality a column) for shipping out,
-% or to commit deferred floats to the fresh column, concluding with a dead cycle.
-% In the former case, we accomodate split footnotes and other insertions (by comparing \cmd\vsize\ and \cmd\pagegoal):
-% the floats are spewed onto the page, whereupon \LaTeX's output routine will place the footnotes and ship out,
-% iterating the process once again.
-%
-% Note that when this procedure is invoked, \cmd\box\cmd\@cclv\ still has within it the protection box, so we
-% start by removing it. Note also that if there was a split insertion held over from the previous page, the
-% insert node will be present in \cmd\box\cmd\@cclv, \emph{prior to} the protection box. For this reason, we cannot 
-% just throw away that box, as we might be tempted to do. 
-%
-% FIXME: where else do we possibly inappropriately discard \cmd\box\cmd\@cclv?
-%
-% Note that, because a column or page page had previously just been completed, 
-% we can assume that there is nothing of importance on the page,
-% and because no message is being passed, we can preserve marks in a simple way.
-%
-% A Note on terminology:
-% In a single-column page grid, you might expect that we would execute the procedure \cmd\do@startpage.
-% But this is not so.
-% \LaTeX\ has a confustion of long standing,
-% in which the procedures that handle full-page width floats in a two-column page grid all have in their names
-% the string `dbl', which erroneously suggests having something to do with ``double''. It does not:
-% when you see `dbl', think ``full page width''.
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-%    \begin{macrocode}
-\mathchardef\do@startcolumn@pen=10005
-\@namedef{output@-\the\do@startcolumn@pen}{\do@startcolumn}%
-\def\do@startcolumn{%
- \setbox\@cclv\vbox{\unvbox\@cclv\remove@lastbox\unskip}%
- \clearpage@sw{\@clearfloatplacement}{\@floatplacement}%
- \set@colht
- \@booleanfalse\pfloat@avail@sw
- \begingroup
-  \@colht\@colroom
-  \@booleanfalse\float@avail@sw
-  \@tryfcolumn\test@colfloat
-  \float@avail@sw{\aftergroup\@booleantrue\aftergroup\pfloat@avail@sw}{}%
- \endgroup
- \fcolmade@sw{%
-  \setbox\@cclv\vbox{\unvbox\@outputbox\unvbox\@cclv}%
-%    \end{macrocode}
-% Now ask for a return visit, this time with insertions and all.
-%    \begin{macrocode}
-  \outputpenalty-\pagebreak@pen
-  \dead@cycle
- }{%
-  \begingroup
-   \let\@elt\@scolelt
-   \let\reserved@b\@deferlist\global\let\@deferlist\@empty\reserved@b
-  \endgroup
-  \clearpage@sw{%
-   \outputpenalty\@M
-  }{%
-   \outputpenalty\do@newpage@pen
-  }%
-  \dead@cycle
- }%
- \check@deferlist@stuck\do@startcolumn
- \set@vsize
-}%
-\def\@scolelt#1{\def\@currbox{#1}\@addtonextcol}%
-\def\test@colfloat#1{%
- \csname @floatselect@sw@\thepagegrid\endcsname#1{}{\@testtrue}%
- \@if@sw\if@test\fi{}{\aftergroup\@booleantrue\aftergroup\float@avail@sw}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@addtonextcol}
-% We must adjust \cmd\@addtonextcol\ to take held-over inserts into account.
-% Now that all deferred floats are queued up together (in order), we must have a way of 
-% differentiating them; this is done by the page grid-dependent procedure \cmd\@floatselect@sw@.
-%    \begin{macrocode}
-\def\@addtonextcol{%
- \begingroup
-  \@insertfalse
-  \@setfloattypecounts
-  \csname @floatselect@sw@\thepagegrid\endcsname\@currbox{%
-   \@ifnum{\@fpstype=8 }{}{%
-     \@ifnum{\@fpstype=24 }{}{%
-       \@flsettextmin
-       \@reqcolroom \ht\@currbox
-       \advance \@reqcolroom \@textmin
-       \advance \@reqcolroom \vsize % take into account split insertions
-       \advance \@reqcolroom -\pagegoal
-       \@ifdim{\@colroom>\@reqcolroom}{%
-         \@flsetnum \@colnum
-         \@ifnum{\@colnum>\z@}{%
-            \@bitor\@currtype\@deferlist
-            \@if@sw\if@test\fi{}{%
-              \@addtotoporbot
-            }%
-         }{}%
-       }{}%
-     }%
-   }%
-  }{}%
-  \@if@sw\if@insert\fi{}{%
-    \@cons\@deferlist\@currbox
-  }%
- \endgroup
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\do@startpage@pen}
-% \begin{macro}{\forcefloats@sw}
-% \begin{macro}{\@output@combined@page}
-% \begin{macro}{\@sdblcolelt}
-% \begin{macro}{\test@dblfloat}
-% \begin{macro}{\@if@notdblfloat}
-% Similar to \cmd\do@startcolumn,
-% the procedure \cmd\do@startpage\ starts up a new page (not column) in a multi-column page grid. 
-% It is invoked after a page is shipped out in a multi-column page grid, and
-% it commits full-page-width floats to the fresh page, possibly resulting in a float page.
-% In implementation, it is similar to \cmd\do@startcolumn, except that
-% it commits effectively via \cmd\@addtodblcol\ instead of \cmd\@addtonextcol.
-% Note that this procedure will inevitably be followed by \cmd\do@startcolumn.
-%
-% Some details of the procedure:
-%
-% We begin by removing the protection box from \cmd\box\cmd\@cclv, then setting the values of the
-% float placement parameters appropriately, and resetting \cmd\@colht, \cmd\@colroom, and \cmd\vsize\ to base values.
-%
-% Next we attempt to compose a float page, a page consisting entirely of floats. If successful,
-% we ship out the float page and lay down an interrupt that will send us back here for another try.
-%
-% If no float page is formed, we attempt to commit full-page-width floats to the text page, and return with a dead cycle.
-% We are now ready to compose columns of text.
-%
-% Note that all floats (both column floats and full-page-width floats) move through a single queue.
-% To differentiate between the two, the width of the float is compared to \cmd\textwidth.
-% This comparison is encapsulated in the macro \cmd\@if@notdblfloat, which should be used whenever 
-% such a determination must be made. This procedure returns a Boolean.
-%
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-%    \begin{macrocode}
-\mathchardef\do@startpage@pen=10006
-\@namedef{output@-\the\do@startpage@pen}{\do@startpage}%
-\def\do@startpage{%
- \setbox\@cclv\vbox{\unvbox\@cclv\remove@lastbox\unskip}%
- \clearpage@sw{\@clearfloatplacement}{\@dblfloatplacement}%
- \set@colht
- \@booleanfalse\pfloat@avail@sw
- \begingroup
-  \@booleanfalse\float@avail@sw
-  \@tryfcolumn\test@dblfloat
-  \float@avail@sw{\aftergroup\@booleantrue\aftergroup\pfloat@avail@sw}{}%
- \endgroup
- \fcolmade@sw{%
-  \global\setbox\pagesofar\vbox{\unvbox\pagesofar\unvbox\@outputbox}%
-  \@output@combined@page
- }{%
-  \begingroup
-   \@booleanfalse\float@avail@sw
-   \let\@elt\@sdblcolelt
-   \let\reserved@b\@deferlist\global\let\@deferlist\@empty\reserved@b
-  \endgroup
-  \@ifdim{\@colht=\textheight}{% No luck...
-   \pfloat@avail@sw{% ...but a float *was* available!
-    \forcefloats@sw{%
-     \ltxgrid@warn{Forced dequeueing of floats stalled}%
-    }{%
-     \ltxgrid@warn{Dequeueing of floats stalled}%
-    }%
-   }{}%
-  }{}%
-  \outputpenalty\@M
-  \dead@cycle
- }%
- \check@deferlist@stuck\do@startpage
- \set@colht
-}%
-%    \end{macrocode}
-%
-% Procedure \cmd\@output@combined@page\ is a utility that ships out a page consisting of the
-% result of \cmd\@combinepage\ and \cmd\@combinedblfloats, after which it prepares for 
-% the process to repeat.
-%
-% It is coincidentally identical to what needs to happen with 
-% a float page that has been built by \cmd\@tryfcolumn, in the multi-column page grid, 
-% and also handles the case where a page needs to be shipped out when in multicolumn mode.
-% \changes{4.1b}{2008/08/04}{New procedure \cs{@output@combined@page}}
-% \changes{4.1b}{2008/08/04}{Change \cs{@combinepage} to \cs{@combinepage} with argument}
-%    \begin{macrocode}
-\def\@output@combined@page{%
- \@combinepage\true@sw
- \@combinedblfloats
- \@outputpage
- \global\pagegrid@cur\@ne
- \protect@penalty\do@startpage@pen
-}%
-\def\@sdblcolelt#1{\def\@currbox{#1}\@addtodblcol}%
-\def\test@dblfloat#1{%
- \@if@notdblfloat{#1}{\@testtrue}{}%
- \@if@sw\if@test\fi{}{\aftergroup\@booleantrue\aftergroup\float@avail@sw}%
-}%
-\def\@if@notdblfloat#1{\@ifdim{\wd#1<\textwidth}}%
-\@booleanfalse\forcefloats@sw
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@addtodblcol}
-%
-% The procedure \cmd\@addtodblcol\ is called into play at the beginning of each fresh page
-% and operates on each deferred float, in the hopes of placing one or more such floats
-% at the top of the current page.
-% 
-% We alter the procedure of standard \LaTeX\ by putting failed floats into 
-% \cmd\@deferlist\ instead of \cmd\@dbldeferlist. Having done so, we must have a means
-% of differentiating full-page-width floats from column-width floats.
-% We assume that the latter will always be narrower than \cmd\textwidth.
-%
-% In aid of detecting a stalled float flushing process, we set a Boolean if we encounter
-% a qualified full-page-width float here. Any that qualify but fail the rest of the tests
-% might still pass when reconsidered on an otherwise blank page.
-%    \begin{macrocode}
-\def\@addtodblcol{%
- \begingroup
-  \@if@notdblfloat{\@currbox}{%
-   \false@sw
-  }{%
-   \@setfloattypecounts
-   \@getfpsbit \tw@
-   \@bitor \@currtype \@deferlist
-   \@if@sw\if@test\fi{%
-    \false@sw
-   }{%
-    \@ifodd\@tempcnta{%
-     \aftergroup\@booleantrue\aftergroup\float@avail@sw
-     \@flsetnum \@dbltopnum
-     \@ifnum{\@dbltopnum>\z@}{%
-       \@ifdim{\@dbltoproom>\ht\@currbox}{%
-        \true@sw
-       }{%
-        \@ifnum{\@fpstype<\sixt@@n}{%
-         \begingroup
-          \advance \@dbltoproom \@textmin
-          \@ifdim{\@dbltoproom>\ht\@currbox}{%
-           \endgroup\true@sw
-          }{%
-           \endgroup\false@sw
-          }%
-        }{%
-         \false@sw
-        }%
-       }%
-     }{%
-      \false@sw
-     }%
-    }{%
-     \false@sw
-    }%
-   }%
-  }%
-  {%
-   \@tempdima -\ht\@currbox
-   \advance\@tempdima
-    -\@ifx{\@dbltoplist\@empty}{\dbltextfloatsep}{\dblfloatsep}%
-   \global \advance \@dbltoproom \@tempdima
-   \global \advance \@colht \@tempdima
-   \global \advance \@dbltopnum \m@ne
-   \@cons \@dbltoplist \@currbox
-  }{%
-   \@cons \@deferlist \@currbox
-  }%
- \endgroup
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@tryfcolumn}
-% \begin{macro}{\@wtryfc}
-% \begin{macro}{\@xtryfc}
-% \begin{macro}{\@ztryfc}
-% Whenever a page is shipped out, \LaTeX\ automatically tries out a float column:
-% a page containing nothing but floats (and, as we have added here, split footnotes).
-%
-% The following four procedures employ certain macros to communicate between each other:
-%
-% \cmd\fcolmade@sw, a boolean, says whether we were successful in making a float column.
-%
-% \cmd\if@test, a \cmd\newif\ switch, says a float has failed some test.
-% 
-% \cmd\@deferlist, is the input to the process, a list, of deferred floats.
-% 
-% \cmd\@trylist, a list, stores the deferred floats to be tried out on the float column.
-%
-% \cmd\@failedlist, a list of floats that have failed the selection for the float column.
-%
-% \cmd\@flfail, a list of floats that have failed the second selection for the float column.
-%
-% \cmd\@flsucceed, a list, the floats that have been successfully placed on the float column.
-%
-% \cmd\@freelist, a list, receives any freed floats.
-%
-% \cmd\@colht, a dimen, the available space for the column, including column floats and insertions (footnotes).
-%
-% \cmd\@fpmin, a dimen, the required minimum height for the float column.
-%
-% \cmd\@outputbox, a box, the output of the process.
-%
-% \cmd\@fptop, \cmd\@fpsep, \cmd\@fpbot, glue, placed above, between, and below floats on the float column.
-%
-% \cmd\@currtype, a count, used temporarily for the float's bits.
-%
-% \cmd\@tempcnta, a count, used temporarily for the float's bits.
-%
-% In \cmd\@tryfcolumn, we alter the criterion for a float page, because if footnotes are present at this point
-% (presumably due to a split insertion) then \cmd\@fpmin is no longer the right threshold to apply.
-% 
-% Note that we have changed \cmd\@tryfcolumn, \cmd\@xtryfc, and \cmd\@ztryfc\ syntactically so that the procedure
-% to test for the float's being a column float versus a full-page-width float is passed in as an 
-% argument.
-%
-%    \begin{macrocode}
-\def\@tryfcolumn#1{%
-  \global\@booleanfalse\fcolmade@sw
-  \@ifx@empty\@deferlist{}{%
-    \global\let\@trylist\@deferlist
-    \global\let\@failedlist\@empty
-    \begingroup
-      \dimen@\vsize\advance\dimen@-\pagegoal\@ifdim{\dimen@>\z@}{%
-       \advance\@fpmin-\dimen@
-      }{}%
-      \def\@elt{\@xtryfc#1}\@trylist
-    \endgroup
-    \fcolmade@sw{%
-      \global\setbox\@outputbox\vbox{\vskip \@fptop}%
-      \let \@elt \@wtryfc \@flsucceed
-      \global\setbox\@outputbox\vbox{\unvbox\@outputbox
-        \unskip \vskip \@fpbot
-      }%
-      \let \@elt \relax
-      \xdef\@deferlist{\@failedlist\@flfail}%
-      \xdef\@freelist{\@freelist\@flsucceed}%
-    }{}%
-  }%
-}%
-\def\@wtryfc #1{%
-  \global\setbox\@outputbox\vbox{\unvbox\@outputbox
-    \box #1\vskip\@fpsep
-  }%
-}%
-\def\@xtryfc#1#2{%
-  \@next\reserved@a\@trylist{}{}% trim \@trylist. Ugly!
-  \@currtype \count #2%
-  \divide\@currtype\@xxxii\multiply\@currtype\@xxxii
-  \@bitor \@currtype \@failedlist
-  \@testfp #2%
-  #1#2%
-  \@ifdim{\ht #2>\@colht   }{\@testtrue}{}%
-  \@if@sw\if@test\fi{%
-   \@cons\@failedlist #2%
-  }{%
-   \begingroup
-     \gdef\@flsucceed{\@elt #2}%
-     \global\let\@flfail\@empty
-     \@tempdima\ht #2%
-     \def \@elt {\@ztryfc#1}\@trylist
-     \@ifdim{\@tempdima >\@fpmin}{%
-       \global\@booleantrue\fcolmade@sw
-     }{%
-       \@cons\@failedlist #2%
-     }%
-   \endgroup
-   \fcolmade@sw{%
-     \let \@elt \@gobble
-   }{}%
-  }%
-}%
-\def\@ztryfc #1#2{%
-  \@tempcnta \count#2%
-  \divide\@tempcnta\@xxxii\multiply\@tempcnta\@xxxii
-  \@bitor \@tempcnta {\@failedlist \@flfail}%
-  \@testfp #2%
-  #1#2%
-  \@tempdimb\@tempdima
-  \advance\@tempdimb \ht#2\advance\@tempdimb\@fpsep
-  \@ifdim{\@tempdimb >\@colht}{%
-    \@testtrue
-  }{}%
-  \@if@sw\if@test\fi{%
-    \@cons\@flfail #2%
-  }{%
-    \@cons\@flsucceed #2%
-    \@tempdima\@tempdimb
-  }%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Clearing pages}%
-% 
-% Clearing the page is an elaboration of ending the page: it entails flushing all floats.
-%
-% This package might make number of float flushing algorithms available,
-% a very simple one that does not try to produce excellent pages,
-% another that tries to make the best use of space,
-% and a more complex one that tries to balance columns.
-% 
-% At the beginning of the page-clearing process, by definition all of the paragraph text involved is on the MVL and all floats have been encountered.
-% There may be material in \cmd\pagesofar, and (in a multi-column page grid) any number of columns of the page have been composed.
-% Also, there might be footnote material saved up in \cmd\footsofar.
-% 
-% Because we did not want to perform multiple \cmd\shipout s per visit to the output routine,
-% our multi-column page makeup will not compose multiple columns per visit.
-% This implementation detail may not require alteration, but it is not a limitation that is truly necessary:
-% it is only multiple \cmd\shipout s per visit that must be avoided.
-% 
-% The crux matter is how to continue with flushing floats even after the material in the MVL is exhausted.
-% At that point, we must, upon completion of the output routine, 
-% insert into the MVL an interrupt that triggers the next step in the processing.
-%
-% Therefore, after processing a \cmd\do@startcolumn\ interrupt, we must somehow force the completion of that column.
-% This could be done by inserting a \cmd\do@newpage@pen\ interrupt.
-% 
-% And after processing a \cmd\do@startpage@pen\ interrupt, that results in \cmd\@dbltopinsert s,
-% we must ensure that the multiple columns on the page get completed, so that the page itself finally gets shipped out.
-% This part will proceed automatically given that \cmd\do@startcolumn\ processing completes successfully.
-% 
-% The process will not be complete until all deferred floats have been placed and shipped out, and all saved-up footnotes have been inserted.
-% 
-% Full-page-width floats can get out of order of column floats. This problem can be remedied by holding them all in the same list.
-% We therefore stop using \cmd\@dbldeferlist\ entirely, and all of the procedures that formerly used it have been rewritten to
-% use \cmd\@deferlist\ instead. When traversing the list, we apply a selector on the given box that determines whether it is a column-width or page-width float.
-% This selector is different depending on the page grid.
-%
-% When the \cmd\@deferlist\ is processed (by any means), we have to take care of the case where a float of one category is passed over but we are looking for a float of the other category.
-% Here, we must terminate processing, to avoid disordering the floats. This we do by the usual means.
-% 
-% The system has a Boolean that says we are clearing pages: \cmd\clearpage@sw; if it is true,
-% then at the tail of \cmd\do@startcolumn\ processing, we should put down a (\cmd\vfil?) \cmd\do@newpage@pen\ interrupt.
-% This is because the MVL is now empty, so we have to force the columns to complete.
-% 
-% One potential very pathological case would be where there is one or more deferred floats that never successfully get placed:
-% placing floats has stalled, and we will ship out blank pages indefinitely. How to detect this case?
-% 
-% First, \cmd\do@startpage\ will evidently be stalled if the following are all true:
-% a) \cmd\@tryfcolumn\ and \cmd\@sdblcolelt\ both fail,
-% b) there are deferred floats available for page placement, and
-% c) the \cmd\@colht=\cmd\textheight, that is, the full page height is available for placement of column floats.
-% 
-% Second, \cmd\do@startcolumn\ will evidently be stalled if the following are all true:
-% a) tryfcolumn fails,
-% b) there are deferred floats available for column placement, and
-% a) the \cmd\@colroom=\cmd\textheight, that is, the full page height is available for placement of column floats.
-% 
-%
-% \begin{macro}{\cleardoublepage}
-% \begin{macro}{\clearpage}
-% \begin{macro}{\newpage}
-% \begin{macro}{\newpage@prep}
-% The function of \cmd\clearpage\ is to end the current page with \cmd\newpage\ and then
-% ship out additional pages until (\footins) inserts and (deferred) floats are exhausted.
-%
-% The method involves setting the float placement parameters to completely permissive values
-% and kicking out the current page (using a non-discardable penalty).
-% A possibly short page will be shipped out, followed
-% by any number of float pages. However these float pages, because using permissive float placement,
-% will exhaust all inserts and deferred floats.
-%
-% Bug Note: in the code for \cmd\clearpage, the first penalty we output is an unprotected \cmd\pagebreak@pen.
-% I tried using a protected \cmd\do@newpage@pen, but that gave rise to a corner case where a blank page
-% was output.
-%
-% At present, the \cmd\clearpage\ procedure does the same as \cmd\newpage,
-% except that \cmd\clearpage@sw\ is turned on,
-% and the (discardable) \cmd\newpage\ is inevitably followed by the same procedures
-% that are executed if a page is shipped out.
-%
-% FIXME: it seems that better than \cmd\pagebreak@pen\ would be an unprotected penalty of a special value that would
-% entail output routine processing consisting of the following steps:
-% 3) \cmd\unvbox\cmd\@cclv,
-% 1) set \cmd\clearpage@sw\ to \cmd\true@sw,
-% 2) put down a protected \cmd\do@startcolumn@pen,
-% 4) take a dead cycle.
-%
-% The effect would be to liberalize float placement options for the current column as well as further columns that may be output as part of \cmd\clearpage\ processing.
-% Of course, it would still be necessary to set \cmd\clearpage@sw\ again via an interrupt.
-%
-% An optimization might be to clear \cmd\clearpage@sw\ as part of the same interrupt,
-% but that would actually not work properly, because it is necessary for \cmd\do@endpage\ to
-% possibly invoke further visits to the output routine before clearpage processing ceases.
-%    \begin{macrocode}
-\def\newpage@prep{%
-  \if@noskipsec
-    \ifx \@nodocument\relax
-      \leavevmode
-      \global \@noskipsecfalse
-    \fi
-  \fi
-  \if@inlabel
-    \leavevmode
-    \global \@inlabelfalse
-  \fi
-  \if@nobreak \@nobreakfalse \everypar{}\fi
-  \par
-}%
-\def \newpage {%
- \newpage@prep
- \do@output@MVL{%
-  \vfil
-  \penalty-\pagebreak@pen
- }%
-}%
-\def\clearpage{%
- \newpage@prep
- \do@output@MVL{%
-  \vfil
-  \penalty-\pagebreak@pen
-  \global\@booleantrue\clearpage@sw
-  \protect@penalty\do@startcolumn@pen
-  \protect@penalty\do@endpage@pen
- }%
- \do@output@MVL{%
-  \global\@booleanfalse\clearpage@sw
- }%
-}%
-\def\cleardoublepage{%
- \clearpage
- \@if@sw\if@twoside\fi{%
-  \@ifodd\c@page{}{%
-   \null\clearpage
-  }%
- }{}%
-}%
-\@booleanfalse\clearpage@sw
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\do@endpage@pen}
-% The penalty \cmd\do@endpage@pen\ simply dispatches to the page grid procedure that forces an end page.
-% That procedure should test whether there is anything to ship out (say committed floats), then act accordingly.
-% Note that as part of this work, it should \cmd\unvbox\cmd\@cclv, which has been left boxed up so it can be 
-% measured.
-%    \begin{macrocode}
-\mathchardef\do@endpage@pen=10007
-\@namedef{output@-\the\do@endpage@pen}{\csname end@column@\thepagegrid\endcsname}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\do@newpage@pen}
-% The penalty \cmd\do@newpage@pen\ allows a ``non-discardable \cmd\newpage'' command:
-% a \cmd\newpage\ command that will not disappear at a pagebreak.
-% This visit to the output routine will not be dispatched to an interrupt,
-% rather the natural output routine will be executed, where it
-% will remove the protection box.
-% 
-% Call this routine by executing \cmd\protect@penalty\cmd\do@newpage@pen.
-%    \begin{macrocode}
-\mathchardef\do@newpage@pen=10001
-\expandafter\let\csname output@-\the\do@newpage@pen\endcsname\relax
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@clearfloatplacement}
-% The procedure \cmd\@clearfloatplacement\ sets the float placement parameters
-% to completely permissive values (except for \cmd\@fpmin). The standard values are:
-%
-% \begin{tabular}{ll}
-%\cmd\@topnum      &\cmd\c@topnumber\\
-%\cmd\@toproom     &\cmd\topfraction\cmd\@colht\\
-%\cmd\@botnum      &\cmd\c@bottomnumber\\
-%\cmd\@botroom     &\cmd\bottomfraction\cmd\@colht\\
-%\cmd\@colnum      &\cmd\c@totalnumber\\
-%\cmd\@fpmin       &\cmd\floatpagefraction\cmd\@colht\\
-%\cmd\@dbltopnum   &\cmd\c@dbltopnumber\\
-%\cmd\@dbltoproom  &\cmd\dbltopfraction\cmd\@colht\\
-%\cmd\@textmin     &\cmd\@colht\cmd\advance\cmd\@textmin -\cmd\@dbltoproom\\
-%\cmd\@fpmin       &\cmd\dblfloatpagefraction\cmd\textheight
-% \end{tabular}
-%    \begin{macrocode}
-\def\@clearfloatplacement{%
- \global\@topnum     \maxdimen
- \global\@toproom    \maxdimen
- \global\@botnum     \maxdimen
- \global\@botroom    \maxdimen
- \global\@colnum     \maxdimen
- \global\@dbltopnum  \maxdimen
- \global\@dbltoproom \maxdimen
- \global\@textmin    \z@      
- \global\@fpmin      \z@      
- \let\@testfp\@gobble
- \appdef\@setfloattypecounts{\@fpstype16\advance\@fpstype\m@ne}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@doclearpage}
-% \begin{macro}{\@makefcolumn}
-% \begin{macro}{\@makecol}
-% The \cmd\@doclearpage\ procedure is now obsoleted, as is \cmd\@makefcolumn, which it invoked.
-% We also completely avoid using \cmd\@makecol\ (in favor of \cmd\@makecolumn).
-%    \begin{macrocode}
-\let\@doclearpage\@undefined
-\let\@makefcolumn\@undefined
-\let\@makecol\@undefined
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\clr@top@firstmark}
-% \begin{macro}{\set@top@firstmark}
-% \begin{macro}{\@outputpage@tail}
-% We want accurate values of \cmd\topmark\ and \cmd\firstmark, but we must deal with 
-% the fact that there are many different ways of contributing material
-% to the page. Only upon the first contribution to the page is the value of \cmd\topmark\
-% accurate. However, with \cmd\firstmark\ we must potentially examine each contribution
-% because the first mark on the page may happen to fall in the last piece of material contributed.
-%
-% To begin, we define the procedure that initializes the macros to appropriate flag values.
-%    \begin{macrocode}
-\def\clr@top@firstmark{%
- \global\let\saved@@topmark\@undefined
- \global\let\saved@@firstmark\@empty
- \global\let\saved@@botmark\@empty
-}%
-\clr@top@firstmark
-%    \end{macrocode}
-%
-% Note that the flag value for \cmd\saved@@topmark\ is \cmd\@undefined, just as one would
-% expect. But that for \cmd\saved@@firstmark\ and \cmd\saved@@botmark\ is \cmd\@empty.
-%
-% Next, we define procedure \cmd\set@top@firstmark; it will be exercised everywhere material is contributed,
-% capturing the mark values if appropriate.
-%    \begin{macrocode}
-\def\set@top@firstmark{%
- \@ifxundefined\saved@@topmark{\expandafter\gdef\expandafter\saved@@topmark\expandafter{\@@topmark}}{}%
- \@if@empty\saved@@firstmark{\expandafter\gdef\expandafter\saved@@firstmark\expandafter{\@@firstmark}}{}%
- \@if@empty\@@botmark{}{\expandafter\gdef\expandafter\saved@@botmark\expandafter{\@@botmark}}%
-}%
-%    \end{macrocode}
-% When should \cmd\set@top@firstmark\ be called?
-% A good candidate for a universal procedure for handling contributed material is
-% the natural output routine; are any other calls needed?
-%
-% Yes, in \cmd\save@column\ we must execute \cmd\set@top@firstmark\ because we are about to 
-% save away \cmd\box\cmd\@cclv, and we will never see its marks again (unless it is unboxed into the MVL),
-% because \TeX\ lets one access a box's marks only within an output routine that has put that box into \cmd\box\cmd\@cclv.
-%
-% As soon as a page is shipped out, we initialize the two macros that
-% hold the values of \cmd\topmark\ and \cmd\firstmark, respectively.
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@tail} tailpatches \cs{@outputpage}}%
-%    \begin{macrocode}
-\appdef\@outputpage@tail{%
- \clr@top@firstmark
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Other interfaces to \LaTeX}%
-%
-% \begin{macro}{\@float}
-% \begin{macro}{\@dblfloat}
-% \begin{macro}{\@yfloat}
-% \begin{macro}{\fps@}
-% \begin{macro}{\fpsd@}
-% The \LaTeX\ kernel procedures \cmd\@float\ and \cmd\@dblfloat\ are treated on an equal footing.
-% Each now takes environment-specific float placement defaults.
-% If none are defined for the calling environment, we apply a default.
-%
-% A parameter is passed that will set the width of text within the float, normally \cmd\columnwidth,
-% and in the "dbl" version, \cmd\textwidth. However, an environment such as \env{turnpage}
-% may change the meanings of these macros to allow turnpage floats.
-%
-% \changes{4.0a}{2008/06/26 }{\cs{@yfloat}: de-fang \cs{set@footnotewidth} (see ltxutil.dtx): we have already done its job. }
-%
-% Note on \cmd\@xfloat: the optional argument must come to it fully expanded, because the macro
-% does a weird procedure on this argument, involving \cmd\@onelevel@sanitize, which I do not
-% understand, and which does not work if not so expanded. 
-% \changes{4.1b}{2008/08/04}{Get rid of the \cs{reserved@a} idiom}
-%    \begin{macrocode}
-\def\@float#1{%
- \@ifnextchar[{%
-%    \end{macrocode}
-% \verb+}]{+Brace-matching klootch
-%    \begin{macrocode}
-  \@yfloat\width@float{#1}%
- }{%
-  \@ifxundefined@cs{fps@#1}{}{\expandafter\let\expandafter\fps@\csname fps@#1\endcsname}%
-  \expandafter\@argswap\expandafter{\expandafter[\fps@]}{\@yfloat\width@float{#1}}%
- }%
-}%
-\def\@dblfloat#1{%
- \@ifnum{\pagegrid@col=\@ne}{%
-  \@float{#1}%
- }{%
-  \@ifnextchar[{%
-%    \end{macrocode}
-% \verb+}]{+Brace-matching klootch
-%    \begin{macrocode}
-   \@yfloat\widthd@float{#1}%
-  }{%
-   \@ifxundefined@cs{fpsd@#1}{}{\expandafter\let\expandafter\fpsd@\csname fpsd@#1\endcsname}%
-   \expandafter\@argswap\expandafter{\expandafter[\fpsd@]}{\@yfloat\widthd@float{#1}}%
-  }%
- }%
-}%
-%    \end{macrocode}
-% \changes{4.1b}{2008/08/04}{Turn off the \cs{set@footnotewidth} mechanism; a float `knows' its proper typesetting context}
-% \changes{4.1n}{2010/01/02}{(AO, 571) Interface \cs{set@footnotewidth} for determining the set width of footnotes}%
-% \cmd\@yfloat\ is the go-to procdure for creating the proper environment for the content of a float.
-% Argument \verb+#1+ is the width of the float environment (we disable \cmd\set@footnotewidth), and 
-% we establish a self-contained (minipage) environment for footnotes. 
-%    \begin{macrocode}
-\def\@yfloat#1#2[#3]{%
- \@xfloat{#2}[#3]%
- \hsize#1\linewidth\hsize
- \let\set@footnotewidth\@empty
- \minipagefootnote@init
-}%
-\def\fps@{tbp}%
-\def\fpsd@{tp}%
-\def\width@float{\columnwidth}%
-\def\widthd@float{\textwidth}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\end@float}
-% \begin{macro}{\end@dblfloat}
-% \begin{macro}{\end@@float}
-% \begin{macro}{\check@currbox@count}
-% \begin{macro}{\minipagefootnote@init}
-% \begin{macro}{\minipagefootnote@here}
-% \LaTeX\ kernel procedures \cmd\end@float\ and \cmd\end@dblfloat\
-% have been changed to work alike; in particular, floats of both classes
-% are deferred into the same queue.
-% This measure ensures that they will be placed in their original order, 
-% an aspect in which \LaTeX\ is broken.
-%
-% Note: when retrieving floats from the queues, we can differentiate those of the two categories
-% by the width of the box.
-%
-% Floats are processed via an output routine message, and are checked for 
-% sanity in re the float placement options. In the case of full-page-width floats,
-% we ensure that the h and b float placement options are never asserted, because they
-% make no sense.
-%
-% Note that if we get to the end of the float box and still have pending
-% footnotes, we put then out.
-%
-% LaTeX Bug note: if a user types \cmd\begin{table*}[h], the float will never succeed in being placed!
-% we try to catch such cases.
-%
-% Note that the macro \cmd\check@currbox@count\ tries to catch cases where the float placement options
-% are such that the float can never be placed.
-%
-% The calls to \cmd\@iffpsbit\ are part of a procedure to deny certain of the float placement
-% parameters: ``h'' and ``b'' are not possible, the former because the \cmd\marginpar\ mechanism
-% cannot place a full-page-width float within a multicolumn page grid, the latter because nobody
-% has yet written the code to do so (pretty bad reason, I know).
-% \changes{4.1b}{2008/08/04}{New procedure \cs{@iffpsbit} replaces \cs{@getfpsbit}}
-%    \begin{macrocode}
-\def\end@float{%
- \end@@float{%
-  \check@currbox@count
- }%
-}%
-\def\end@dblfloat{%
- \@ifnum{\pagegrid@col=\@ne}{%
-  \end@float
- }{%
-  \end@@float{%
-   \@iffpsbit\@ne{\global\advance\count\@currbox\m@ne}{}%
-   \@iffpsbit\f@ur{\global\advance\count\@currbox-4\relax}{}%
-   \global\wd\@currbox\textwidth % Klootch
-   \check@currbox@count
-  }%
- }%
-}%
-\def\end@@float#1{%
- \minipagefootnote@here
- \@endfloatbox
- #1%
- \@ifnum{\@floatpenalty <\z@}{%
-  \@largefloatcheck
-  \@cons\@currlist\@currbox
-  \@ifnum{\@floatpenalty <-\@Mii}{%
-   \do@output@cclv{\@add@float}%
-  }{%
-   \vadjust{\do@output@cclv{\@add@float}}%
-   \@Esphack
-  }%
- }{}%
-}%
-%    \end{macrocode}
-% The \classname{float} package of Anselm Lingnau fails when used under \classname{ltxgrid}, but
-% we can fix things. 
-% We also repair a bug in that package. 
-%
-% \changes{4.1g}{2009/10/06}{(AO, 531) Fix package \classname{float} }
-%    \begin{macrocode}
-\newcommand\float@end@float{%
- \@endfloatbox
- \global\setbox\@currbox\float@makebox\columnwidth
- \let\@endfloatbox\relax
- \end@float
-}%
-\newcommand\float@end@ltx{%
- \end@@float{%
-  \global\setbox\@currbox\float@makebox\columnwidth
-  \check@currbox@count
- }%
-}%
-\newcommand\newfloat@float[3]{%
- \@namedef{ext@#1}{#3} %!
- \let\float@do=\relax
- \xdef\@tempa{\noexpand\float@exts{\the\float@exts \float@do{#3}}}%
- \@tempa
- \floatplacement{#1}{#2}%
- \@ifundefined{fname@#1}{\floatname{#1}{#1}}{} %!
- \expandafter\edef\csname ftype@#1\endcsname{\value{float@type}}%
- \addtocounter{float@type}{\value{float@type}} %!
- \restylefloat{#1}%
- \expandafter\edef\csname fnum@#1\endcsname{%
-  \expandafter\noexpand\csname fname@#1\endcsname{} %!
-  \expandafter\noexpand\csname the#1\endcsname
- }
- \@ifnextchar[%]
-  {%
-   \float@newx{#1}%
-  }{%
-   \@ifundefined{c@#1}{\newcounter{#1}\@namedef{the#1}{\arabic{#1}}}{}%
-  }%
-}%
-\newcommand\newfloat@ltx[3]{%
- \@namedef{ext@#1}{#3}%
- \let\float@do=\relax
- \xdef\@tempa{\noexpand\float@exts{\the\float@exts \float@do{#3}}}%
- \@tempa
- \floatplacement{#1}{#2}%
- \@ifundefined{fname@#1}{\floatname{#1}{#1}}{}%
- \expandafter\edef\csname ftype@#1\expandafter\endcsname\expandafter{\the\c@float@type}%
- \addtocounter{float@type}{\value{float@type}}%
- \restylefloat{#1}%
- \expandafter\edef\csname fnum@#1\endcsname{%
-  \expandafter\noexpand\csname fname@#1\endcsname{}%
-  \expandafter\noexpand\csname the#1\endcsname
- }
- \@ifnextchar[%]
-  {%
-   \float@newx{#1}%
-  }{%
-   \@ifundefined{c@#1}{\newcounter{#1}\@namedef{the#1}{\arabic{#1}}}{}%
-  }%
-}%
-\appdef\document@inithook{%
- \@ifxundefined\newfloat{}{%
-  \@ifx{\float@end\float@end@float}{%
-   \@ifx{\newfloat\newfloat@float}{\true@sw}{\false@sw}%
-   }{\false@sw}% 
-   {%
-    \class@warn{Repair the float package}%
-    \let\float@end\float@end@ltx
-    \let\newfloat\newfloat@ltx
-   }{%
-    \class@warn{Failed to patch the float package}%
-   }%
- }% 
-}%
-%    \end{macrocode}
-%
-% Boolean procedure \cmd\@iffpsbit\ is similar to the \cmd\@getfpsbit\ of \LaTeX, except
-% that we do not expose the scratch count register or even change its value.
-%    \begin{macrocode}
-\def\@iffpsbit#1{%
- \begingroup
-  \@tempcnta\count\@currbox
-  \divide\@tempcnta#1\relax
-  \@ifodd\@tempcnta{\aftergroup\true@sw}{\aftergroup\false@sw}%
- \endgroup
-}%
-%    \end{macrocode}
-%
-% In procedure \cmd\check@currbox@count, we calculate the net float placement
-% directive (encoded into \cmd\count\ \cmd\@currbox's least significant four bits).
-% If zero, issue a warning.
-% \changes{4.1b}{2008/08/04}{Tally the height of the float}
-%    \begin{macrocode}
-\def\check@currbox@count{%
- \@ifnum{\count\@currbox>\z@}{%
-  \count@\count\@currbox\divide\count@\sixt@@n\multiply\count@\sixt@@n
-  \@tempcnta\count\@currbox\advance\@tempcnta-\count@
-  \@ifnum{\@tempcnta=\z@}{%
-   \ltxgrid@warn{Float cannot be placed}%
-  }{}%
-  \expandafter\tally@float\expandafter{\@captype}%
- }{%
-%    \end{macrocode}
-% In this case, the float is a \cmd\marginpar.
-%    \begin{macrocode}
- }%
-}%
-\providecommand\minipagefootnote@init{}%
-\providecommand\minipagefootnote@here{}%
-\providecommand\tally@float[1]{}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@specialoutput}
-% The \cmd\@add@float\ procedure used to reside in standard \LaTeX's \cmd\@specialoutput,
-% which is no more.
-%
-% Historical Note: \cmd\@specialoutput\ and Lamport's method of an output routine dispatcher
-% is the genesis of our more powerful and refined way of using \TeX's output routine to 
-% safely accomplish page makeup tasks. To it and to him we owe acknowledgement and thanks.
-%    \begin{macrocode}
-\let\@specialoutput\@undefined
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@add@float}
-% In the following, we do not need to execute \cmd\@reinserts, which was wrong anyway, as you cannot
-% reliably recover insertions when they split (unless you have a way of reinserting the captured insertion
-% ahead of the split-off part).
-%
-% Now that full-page-width floats are being processed the same as column floats, we
-% have to nip in here and cause them always to be deferred.
-%
-% At the very end, the \cmd\vsize\ is adjusted for any newly committed float.
-%    \begin{macrocode}
-\def\@add@float{%
- \@pageht\ht\@cclv\@pagedp\dp\@cclv
- \unvbox\@cclv
- \@next\@currbox\@currlist{%
-  \csname @floatselect@sw@\thepagegrid\endcsname\@currbox{%
-   \@ifnum{\count\@currbox>\z@}{%
-    \advance \@pageht \@pagedp
-%    \end{macrocode}
-% Do not assume \cmd\holdinginserts is cleared:
-%    \begin{macrocode}
-    \advance \@pageht \vsize \advance \@pageht -\pagegoal
-%    \end{macrocode}
-% Commit an `h' float:
-%    \begin{macrocode}
-    \@addtocurcol
-   }{%
-    \@addmarginpar
-   }%
-  }{%
-   \@resethfps
-   \@cons\@deferlist\@currbox
-  }%
- }{\@latexbug}%
- \@ifnum{\outputpenalty<\z@}{%
-  \@if@sw\if@nobreak\fi{%
-   \nobreak
-  }{%
-   \addpenalty \interlinepenalty
-  }%
- }{}%
- \set@vsize
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@reinserts}
-% The \cmd\@reinserts\ procedure of standard \LaTeX\ is now obsoleted (it had been erroneous anyway).
-%    \begin{macrocode}
-\let\@reinserts\@undefined
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@addtocurcol}
-% We modify the \cmd\@addtocurcol\ procedure of standard \LaTeX\ 
-% so that a float placed ``here'' may break over pages.
-%    \begin{macrocode}
-\def \@addtocurcol {%
-   \@insertfalse
-   \@setfloattypecounts
-   \ifnum \@fpstype=8
-   \else
-     \ifnum \@fpstype=24
-     \else
-       \@flsettextmin
-       \advance \@textmin \@textfloatsheight
-       \@reqcolroom \@pageht
-       \ifdim \@textmin>\@reqcolroom
-         \@reqcolroom \@textmin
-       \fi
-       \advance \@reqcolroom \ht\@currbox
-       \ifdim \@colroom>\@reqcolroom
-         \@flsetnum \@colnum
-         \ifnum \@colnum>\z@
-           \@bitor\@currtype\@deferlist
-           \if@test
-           \else
-             \@bitor\@currtype\@botlist
-             \if@test
-               \@addtobot
-             \else
-               \ifodd \count\@currbox
-                 \advance \@reqcolroom \intextsep
-                 \ifdim \@colroom>\@reqcolroom
-                   \global \advance \@colnum \m@ne
-                   \global \advance \@textfloatsheight \ht\@currbox
-                   \global \advance \@textfloatsheight 2\intextsep
-                   \@cons \@midlist \@currbox
-                   \if@nobreak
-                     \nobreak
-                     \@nobreakfalse
-                     \everypar{}%
-                   \else
-                     \addpenalty \interlinepenalty
-                   \fi
-                   \vskip \intextsep
-                   \unvbox\@currbox %AO
-                   \penalty\interlinepenalty
-                   \vskip\intextsep
-                   \ifnum\outputpenalty <-\@Mii \vskip -\parskip\fi
-                   \outputpenalty \z@
-                   \@inserttrue
-                 \fi
-               \fi
-               \if@insert
-               \else
-                 \@addtotoporbot
-               \fi
-             \fi
-           \fi
-         \fi
-       \fi
-     \fi
-   \fi
-   \if@insert
-   \else
-     \@resethfps
-     \@cons\@deferlist\@currbox
-   \fi
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\if@twocolumn}
-% The \cmd\newif\ switch \cmd\if@twocolumn\ is entirely unused. However its access words are invoked by
-% \LaTeX's \cmd\document\ procedure, so we de-fang it.
-%    \begin{macrocode}
-\@twocolumnfalse
-\let\@twocolumntrue\@twocolumnfalse
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@addmarginpar}
-% The procedure \cmd\@addmarginpar\ used to access \cmd\if@twocolumn, but that switch is not reliable;
-% the better way is to use \cmd\thepagegrid. We establish a convention for a page-grid-oriented
-% procedure, e.g., \cmd\@addmarginpar@one, that emits a boolean, telling this procedure
-% whether to set the marginpar on the left or right.
-%    \begin{macrocode}
-\def\@addmarginpar{%
- \@next\@marbox\@currlist{%
-  \@cons\@freelist\@marbox\@cons\@freelist\@currbox
- }\@latexbug
- \setbox\@marbox\hb@xt@\columnwidth{%
-  \csname @addmarginpar@\thepagegrid\endcsname{%
-   \hskip-\marginparsep\hskip-\marginparwidth
-   \box\@currbox
-  }{%
-   \hskip\columnwidth\hskip\marginparsep
-   \box\@marbox
-  }%
-  \hss
- }%
- \setbox\z@\box\@currbox
-    \@tempdima\@mparbottom
-    \advance\@tempdima -\@pageht
-    \advance\@tempdima\ht\@marbox
- \@ifdim{\@tempdima >\z@}{%
-   \@latex@warning@no@line {Marginpar on page \thepage\space moved}%
- }{%
-   \@tempdima\z@
- }%
-    \global\@mparbottom\@pageht
-    \global\advance\@mparbottom\@tempdima
-    \global\advance\@mparbottom\dp\@marbox
-    \global\advance\@mparbottom\marginparpush
-    \advance\@tempdima -\ht\@marbox
-    \global\setbox \@marbox
-                   \vbox {\vskip \@tempdima
-                          \box \@marbox}%
-    \global \ht\@marbox \z@
-    \global \dp\@marbox \z@
-    \kern -\@pagedp
-    \nointerlineskip
-  \box\@marbox
-    \nointerlineskip
-    \hbox{\vrule \@height\z@ \@width\z@ \@depth\@pagedp}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{environment}{turnpage}
-% Any float (viz., \env{figure} or \env{table}) within the scope of this environment
-% will be a turnpage float: It will be assumed to occupy an entire page (constitute a float page),
-% the width will be \cmd\textheight, the height \cmd\textwidth, and the entire float will be presented
-% rotated 90 degrees. 
-%
-% The implementation requires the services of the \cmd\rotatebox\ command, so we supply a dummy definition
-% that explains things to the user.
-%    \begin{macrocode}
-\newenvironment{turnpage}{%
- \def\width@float{\textheight}%
- \def\widthd@float{\textheight}%
- \appdef\@endfloatbox{%
-  \@ifxundefined\@currbox{%
-   \ltxgrid@warn{Cannot rotate! Not a float}%
-  }{%
-   \setbox\@currbox\vbox to\textwidth{\vfil\unvbox\@currbox\vfil}%
-   \global\setbox\@currbox\vbox{\rotatebox{90}{\box\@currbox}}%
-  }%
- }%
-}{%
-}%
-\def\rotatebox@dummy#1#2{%
- \ltxgrid@warn{You must load the graphics or graphicx package in order to use the turnpage environment}%
- #2%
-}%
-%    \end{macrocode}
-% \changes{4.1b}{2008/08/04}{Use \cs{document@inithook} instead of \cs{AtBeginDocument}}
-%    \begin{macrocode}
-\appdef\document@inithook{%
- \@ifxundefined\rotatebox{\let\rotatebox\rotatebox@dummy}{}%
-}%
-%    \end{macrocode}
-% \end{environment}
-%
-%
-% \subsection{One-off output routines}
-%
-% These procedures are executed in lieu of \cmd\the\cmd\output\ when the output penalty has the associated flag value.
-%
-% \begin{macro}{output@-1073741824}
-% The first one-off output routine handles the end of the job, wherein
-% \LaTeX\ executes \cmd\@@end, and breaks to the output with a penalty of
-% $"40000000 = 2^{32}/4 = 1073741824$. 
-% We simply discard \cmd\box\cmd\@cclv\ and leave.
-% This means that \LaTeX\ is obligated to do \cmd\clearpage\ as part of
-% its \enve{document} processing, otherwise material will be lost.
-%    \begin{macrocode}
-\@namedef{output@-1073741824}{%
- \deadcycles\z@
-%    \end{macrocode}
-%    \begin{verbatim}
-%\showbox\@cclv
-%    \end{verbatim}
-%    \begin{macrocode}
- \void@cclv
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\save@column@pen}
-% The one-off output routine associated with \cmd\penalty\cmd\save@column@pen\
-% will be called within a sequence of three such routines by \cmd\execute@message
-% or its companion routine \cmd\execute@message@insert.
-% This procedure must save away any the current page and preserve marks.
-%    \begin{macrocode}
-\mathchardef\save@column@pen=10016
-\@namedef{output@-\the\save@column@pen}{\save@column}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@cclv@saved}
-% We take over the \cmd\@holdpg\ box register. Hereafter,
-% we no longer use the \cmd\@holdpg\ box register, so let the world know.
-% This should decisively break packages that assume standard \LaTeX.
-% Breaking decisively is preferred to quietly proceeding erroneously.
-%    \begin{macrocode}
-\let \@cclv@saved \@holdpg
-\let \@holdpg \@undefined
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\save@column}
-% The procedure \cmd\save@column\ does the actual work of saving away the material
-% on the page. It is invoked both by \cmd\save@column@pen\ and by \cmd\save@column@insert@pen.
-% We save \cmd\box\cmd\@cclv\ and the primitive \cmd\@@topmark.
-%    \begin{macrocode}
-\def\save@column{%
- \@ifvoid\@cclv@saved{%
-  \set@top@firstmark
-  \global\@topmark@saved\expandafter{\@@topmark}%
- }{}%
- \global\setbox\@cclv@saved\vbox{%
-  \@ifvoid\@cclv@saved{}{%
-   \unvbox\@cclv@saved
-   \marry@baselines
-  }%
-  \unvbox\@cclv
-  \lose@breaks
-  \remove@lastbox
- }%
-}%
-\newtoks\@topmark@saved
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\prep@cclv}
-% The procedure \cmd\prep@cclv\ is used by message handlers to set up their environment
-% to ape that of the usual output routine, with the boxed-up page in \cmd\box\cmd\@cclv.
-% Here, we retrieve the material from \cmd\@cclv@saved, where it was saved away by
-% the one-off output routine associated with \cmd\save@column@pen.
-%    \begin{macrocode}
-\def\prep@cclv{%
- \void@cclv
- \setbox\@cclv\box\@cclv@saved
- \vbadness\@M
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\save@column@insert@pen}
-% The one-off output routine associated with \cmd\penalty\cmd\save@column@insert@pen\
-% is similar to that of \cmd\save@column@pen\ augmented with the processing of insertions.
-% It is called by \cmd\execute@message@insert\  (i.e., at a grid change)
-% and saves away the current page and preserves marks.
-% In addition, it saves away any insertions that fall on the current page.
-% As with the natural output routine, it executes in two phases,
-% first with \cmd\holdinginserts\ set, then cleared. 
-%    \begin{macrocode}
-\mathchardef\save@column@insert@pen=10017
-\@namedef{output@-\the\save@column@insert@pen}{\toggle@insert{\savecolumn@holding}{\savecolumn@moving}}%
-%    \end{macrocode}
-% The procedure \cmd\savecolumn@holding\ is the first phase of saving a column with its inserts.
-% This phase must detect and remedy the one circumstance that will confound our efforts to propagate marks.
-% It is similar to \cmd\output@holding, except that we have to deal with the protection box, which must
-% remain, because the messaging mechanism is being used.
-%
-% If it appears that we have the pathological ``Big Bad Box'' case at hand, we use the \cmd\dead@cycle@repair@protected\
-% procedure instead of \cmd\dead@cycle\ to do our dead cycle.
-% \changes{4.1b}{2008/08/04}{Use \cs{trace@box} instead of \cs{showbox}}
-%    \begin{macrocode}
-\def\savecolumn@holding{%
- \@if@exceed@pagegoal{\unvcopy\@cclv\remove@lastbox}{%
-  \setbox\z@\vbox{\unvcopy\@cclv\remove@lastbox}%
-  \outputdebug@sw{\trace@box\z@}{}%
-  \dimen@\ht\@cclv\advance\dimen@-\ht\z@
-  \dead@cycle@repair@protected\dimen@
- }{%
-  \dead@cycle
- }%
-}%
-%    \end{macrocode}
-% \changes{4.1b}{2008/08/04}{New procedure for showing a box contents, \cs{trace@box}}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% The procedure \cmd\save@column@moving\ is the second phase of saving a column with its inserts. 
-% Now that \cmd\holdinginserts\ is cleared, we can look in the various \cmd\insert\ registers for 
-% our inserts (at present there is only one, \cmd\footins, along with \cmd\footins@saved). 
-% if anything is there, we save it away and ask for another cycle (because it may have split). 
-% 
-% Note that the message that is about to be executed had better deal properly with the contents of 
-% the \cmd\footins@saved\ box.
-%
-%    \begin{macrocode}
-\def\savecolumn@moving{%
- \ltxgrid@info@sw{\class@info{\string\savecolumn@moving}}{}%
- \@cclv@nontrivial@sw{%
-  \save@column
- }{%
-  \void@cclv
- }%
- \@ifvoid\footins{}{%
-  \ltxgrid@foot@info@sw{\class@info{\string\savecolumn@moving}\trace@scroll{\showbox\footins@saved\showbox\footins}}{}%
-%    \end{macrocode}
-% Save all away in \cmd\footins@saved. Note that if \cmd\footins\ is void, then \cmd\footins@saved\ remains untouched. 
-%    \begin{macrocode}
-  \@ifvoid\footins@saved{%
-   \global\setbox\footins@saved\box\footins
-  }{%
-   \global\setbox\footins@saved\vbox\bgroup
-    \unvbox\footins@saved
-    \marry@baselines
-    \unvbox\footins
-   \egroup
-  }%
-  \ltxgrid@foot@info@sw{\trace@box\footins@saved}{}%
-  \protect@penalty\save@column@insert@pen
- }%
-}%
-\newbox\footins@saved
-\newbox\footins@recovered
-\newbox\column@recovered
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\save@message@pen}
-% The one-off output routine associated with \cmd\penalty\cmd\save@message@pen\
-% saves away the message that has been passed.
-% This procedure is penultimate in a sequence of one-off output routine calls;
-% earlier ones have saved away the MVL and preserved marks, the last executes the message.
-%
-% Note that we are passing tokens to \TeX's primitive \cmd\mark\ mechanism, so we must ensure
-% that they are not inappropriately expanded. We use the same mechanism for all such cases,
-% namely \cmd\let@mark.
-%
-% Note: we expect that \cmd\box\cmd\@cclv's contents are well known:
-% \cmd\topskip, protection box, and a \cmd\mark, the latter containing the message.
-% But if we came here via \cmd\penalty 10017, there might be an \cmd\insert\ node present as well, 
-% because a footnote may have split. 
-% Because this procedure simply voids out \cmd\box\cmd\@cclv, such material would be lost.
-% Perhaps we can repair things by manipulating the \cmd\insert \ mechanism temporarily.
-%    \begin{macrocode}
-\mathchardef\save@message@pen=10018
-\@namedef{output@-\the\save@message@pen}{\save@message}%
-\def\save@message{%
- \void@cclv 
-%    \end{macrocode}
-%FIXME: what if \cmd\box\cmd\@cclv is not empty?
-%    \begin{macrocode}
- \toks@\expandafter{\@@firstmark}%
- \expandafter\gdef\expandafter\@message@saved\expandafter{\the\toks@}%
- \expandafter\do@@mark\expandafter{\the\@topmark@saved}%
-}%
-\gdef\@message@saved{}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\execute@message@pen}
-% The one-off output routine associated with \cmd\execute@message@pen\ 
-% simply executes the given message. It is last in a sequence of one-off output routine calls;
-% earlier ones have saved all that require saving.
-%    \begin{macrocode}
-\mathchardef\execute@message@pen=10019
-\@namedef{output@-\the\execute@message@pen}{\@message@saved}%
-%    \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{Output messages}
-%
-% Message handlers are procedures that execute output messages, tokens that are passed to
-% the output routine for execution in an environment appropriate to page makeup.
-%
-% How it works. We put down three large negative penalties, each of which will be handled by
-% the output dispatcher (\emph{not} the natural output routine), each penalty being protected by
-% a removable, non-discardable item (i.e., a box).
-% Either three or four invocations of one-off output routines are involved per message.
-%
-% We make the last of the three protection boxes have a depth equal to the value of \cmd\prevdepth\
-% that was current when the procedure is called. This effectively restores \cmd\prevdepth.
-%
-% In each case, the one-off output routine will remove the extraneous box we have inserted.
-% And the second and third one-off routines will simply void \cmd\box\cmd\@cclv, because its contents
-% are entirely artificial.
-%
-% FIXME: not so! If \cmd\holdinginserts\ is cleared, that box may have an insert node; it must be preserved, too.
-%
-% The first routine saves away the current column contents and remembers the \cmd\topmark\ for later
-% use. There is a variant routine that first clears \cmd\holdinginserts, so that the message can
-% handle any inserts present in the boxed-up page; this of course entails yet another
-% visit to the output routine.
-%
-% The penultimate routine saves away the tokens transmitted in via the \cmd\@@mark: the argument of
-% the macro. These tokens are of course the very thing we wish to execute within the safety
-% of the output routine. It also puts down a mark containing the \cmd\topmark\ tokens saved
-% by the first routine. By this means, the mark, which we have clobbered, is restored.
-%
-% The last routine simply executes the given tokens.
-% In the course of doing this, it must take care of \cmd\box\cmd\@cclv, either by shipping it out,
-% or by \cmd\unvbox ing it onto the MVL.
-%
-% \begin{macro}{\execute@message}
-% The procedure \cmd\execute@message\ simply calls the utility procedure \cmd\@execute@message\
-% with a penalty value for the standard treatment.
-%    \begin{macrocode}
-\def\execute@message{%
- \@execute@message\save@column@pen
-%    \end{macrocode}
-% Implicit second argument
-%    \begin{macrocode}
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\execute@message@insert}
-% The procedure \cmd\execute@message@insert\ is like \cmd\execute@message\ in all respects
-% except that the penalty value is \cmd\save@column@insert@pen, which arranges for the 
-% message handler involved to deal with the page's insertions.
-% At the same time, we prepare the \cmd\footins\ box so that these insertions can be dealt with.
-%
-% Note:
-% If more insertions are added to \LaTeX\ (presumably via \cmd\newinsert), then they
-% must be dealt with in a way entirely analogous to \cmd\footins.
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\execute@message@insert#1{%
- \@execute@message\save@column@insert@pen{%
-  \setbox \footins \box \footins@saved
-  \ltxgrid@foot@info@sw{\class@info{\string\execute@message@insert}\trace@box\footins}{}%
-  #1%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@execute@message}
-% The utility procedure \cmd\@execute@message\ is called by \cmd\execute@message\ and \cmd\execute@message@insert.
-% We prepare by creating a \cmd\vbox\ containing all the needed nodes and proceed by simply
-% \cmd\unvbox ing that box onto the MVL.
-% We ensure that \cmd\box\cmd\@cclv\ is properly set up for the output message handler
-% by always inserting \cmd\prep@cclv\ in advance of the argument.
-%
-% Note that each one-off output routine is invoked effectively the same as
-% \cmd\protect@penalty, except that the second invocation involves an additional
-% \cmd\mark\ node, and the third a specially prepared protection box.
-%
-% Note also that \TeX's primitive \cmd\mark\ is called here without any expansion protection.
-% This is the only place where it is called that way, but it's OK because those tokens
-% have have been pre-expanded by procedures that call \cmd\execute@message.
-% FIXME: all procedures calling \cmd\execute@message\ must pre-expand their tokens!
-%    \begin{macrocode}
-\long\def\@execute@message#1#2{%
- \begingroup
-  \dimen@\prevdepth\@ifdim{\dimen@<\z@}{\dimen@\z@}{}%
-  \setbox\z@\vbox{%
-   \protect@penalty#1%
-   \protection@box
-   \toks@{\prep@cclv#2}%
-   \@@mark{\the\toks@}%
-   \penalty-\save@message@pen
-%    \end{macrocode}
-%\begin{verbatim}
-%  \hbox{\vrule\@height\z@\@width\z@\@depth\dimen@}%
-%\end{verbatim}
-%    \begin{macrocode}
-   \setbox\z@\null\dp\z@\dimen@\ht\z@-\dimen@
-   \nointerlineskip\box\z@
-   \penalty-\execute@message@pen
-  }\unvbox\z@
- \endgroup
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\do@output@cclv}
-% The procedure \cmd\do@output@cclv\ provides access to message handlers at their simplest.
-% The message will execute in the usual environment of the output routine, with
-% the boxed-up page in \cmd\box\cmd\@cclv, and we assume that \cmd\holdinginserts\ remains set.
-% This procedure must be invoked within main vertical mode;
-% it is the obligation of the macro writer to ensure that this is the case.
-%    \begin{macrocode}
-\def\do@output@cclv{\execute@message}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\do@output@MVL}
-% The procedure \cmd\do@output@MVL, like \cmd\do@output@cclv, is an interface for messages,
-% but provides two additional services: the command may also be invoked in horizontal mode, and
-% the message handler will execute with the MVL unboxed. 
-%    \begin{macrocode}
-\def\do@output@MVL#1{%
- \@ifvmode{%
-  \begingroup\execute@message{\unvbox\@cclv#1}\endgroup
- }{%
-  \@ifhmode{%
-   \vadjust{\execute@message{\unvbox\@cclv#1}}%
-  }{%
-   \@latexerr{\string\do@output@MVL\space cannot be executed in this mode!}\@eha
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\lose@breaks}
-% The purpose of this procedure is to get rid of all the extraneous
-% \cmd\penalty\cmd\@M\ nodes that tend to build up in the MVL.
-%    \begin{macrocode}
-\def\lose@breaks{%
- \loopwhile{%
-  \count@\lastpenalty
-  \@ifnum{\count@=\@M}{%
-%    \end{macrocode}
-% Note: 10000 is a TeX magic number!
-%    \begin{macrocode}
-   \unpenalty\true@sw
-  }{%
-   \false@sw
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\removestuff}
-% \cmd\removestuff\ is a document-level command that removes the bottom skip glue item
-% from the MVL.
-%    \begin{macrocode}
-\def\removestuff{\do@output@MVL{\unskip\unpenalty}}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\removephantombox}
-% The procedure \cmd\removephantombox\ is a special-purpose message handler exclusively for 
-% preventing incorrect spacing above display math. It must be issued in
-% horizontal mode within the phantom paragraph generated when display math starts up in
-% vertical mode.
-%    \begin{macrocode}
-\def\removephantombox{%
- \vadjust{%
-  \execute@message{%
-   \unvbox\@cclv
-   \remove@lastbox
-   \unskip
-   \unskip
-   \unpenalty
-   \penalty\predisplaypenalty
-   \vskip\abovedisplayskip
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\addstuff}
-% \cmd\addstuff\ is a document-level command that adds penalty, glue, or both to the 
-% MVL. The penalty and glue items are rearranged so that all penalties nodes precede all the glue nodes,
-% which is the canonical arrangement.
-%    \begin{macrocode}
-\def\addstuff#1#2{\edef\@tempa{\noexpand\do@output@MVL{\noexpand\@addstuff{#1}{#2}}}\@tempa}%
-\def\@addstuff#1#2{%
- \skip@\lastskip\unskip
- \count@\lastpenalty\unpenalty
- \@if@empty{#1}{}{\penalty#1\relax}%
- \@ifnum{\count@=\z@}{}{\penalty\count@}%
- \vskip\skip@
- \@if@empty{#2}{}{\vskip#2\relax}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\replacestuff}
-% \cmd\replacestuff\ is a document-level command similar to \cmd\addstuff;
-% but it replaces penalty, glue, or both in the MVL.
-% The penalty and glue items are rearranged so that all penalties nodes precede all the glue nodes,
-% which is the canonical arrangement.
-%    \begin{macrocode}
-\def\replacestuff#1#2{\edef\@tempa{\noexpand\do@output@MVL{\noexpand\@replacestuff{#1}{#2}}}\@tempa}%
-\def\@replacestuff#1#2{%
- \skip@\lastskip\unskip
- \count@\lastpenalty\unpenalty
- \@if@empty{#1}{}{%
- \@ifnum{\count@>\@M}{}{%
-   \@ifnum{\count@=\z@}{\count@=#1\relax}{%
-    \@ifnum{\count@<#1\relax}{}{%
-     \count@=#1\relax
-    }%
-   }%
- }%
- }%
- \@ifnum{\count@=\z@}{}{\penalty\count@}%
- \@if@empty{#2}{}{%
-  \@tempskipa#2\relax
-  \@ifdim{\z@>\@tempskipa}{%
-   \advance\skip@-\@tempskipa
-  }{%
-   \@ifdim{\skip@>\@tempskipa}{}{%
-    \skip@\@tempskipa
-   }%
-  }%
- }%
- \vskip\skip@
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\move@insertions}
-% \begin{macro}{\hold@insertions}
-% In order to avoid bolluxing up \cmd\insert\ registers by our one-off 
-% output routines, we set \cmd\holdinginserts\ to zero by default and only 
-% clear it (briefly) while we handle cases where we want inserts to show up.
-%    \begin{macrocode}
-\def\move@insertions{\global\holdinginserts\z@}%
-\def\hold@insertions{\global\holdinginserts\@ne}%
-\hold@insertions
-\def\toggle@insert#1#2{%
- \@ifnum{\holdinginserts>\z@}{\move@insertions#1}{\hold@insertions#2}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Messages to alter the page grid}%
-%
-% Here is the implementation of the grid-switching procedures.
-% We perform two checks when changing the page grid; first to ensure that 
-% the target page grid is known (defensive programming), second to ensure that
-% the switch is a non-trivial one. The latter check must be performed within
-% the safety of the output routine, so requires using an output message.
-% Thus, a grid change requires two messages, for a total of six visits to the output routine.
-%
-% \begin{macro}{\do@columngrid}
-% Utility procedure \cmd\do@columngrid\ changes the page grid.
-% Note that this command forces an end to the current paragraph. This is necessary, because
-% a page grid change makes no sense unless we can alter the \cmd\hsize\ before commencing to
-% typeset the following paragraph. So the command should never be executed in horizontal mode
-% anyway.
-%    \begin{macrocode}
-\def\do@columngrid#1#2{%
- \par
- \expandafter\let\expandafter\@tempa\csname open@column@#1\endcsname
- \@ifx{\relax\@tempa}{%
-  \ltxgrid@warn{Unknown page grid #1. No action taken}%
- }{%
-  \do@output@MVL{\start@column{#1}{#2}}%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\start@column}
-% Procedure \cmd\start@column\ lays down the interrupts to switch the page grid.
-% If the change to the page grid would have been trivial, it bails out.
-% It seems a reasonable tradeoff of processing versus security: once we commit
-% to changing the page grid, we clear \cmd\holdinginserts, so there is no turning back.
-% 
-% Note that the second argument to the macro allows us to pass an argument to the 
-% page grid that is starting up. This can be handy, because a single procedure can 
-% handle multiple page grids, differing only by the value of a parameter.
-%
-% FIXME: this means that you cannot switch between mlt page grids in a single step.
-% But do we want to do this, at all, at all?
-%    \begin{macrocode}
-\def\start@column#1#2{%
- \def\@tempa{#1}\@ifx{\@tempa\thepagegrid}{%
-  \ltxgrid@info{Already in page grid \thepagegrid. No action taken}%
- }{%
-  \expandafter\execute@message@insert
-  \expandafter{%
-               \csname shut@column@\thepagegrid\expandafter\endcsname
-               \csname open@column@#1\endcsname{#2}%
-               \set@vsize
-             }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\thepagegrid}
-% The macro \cmd\thepagegrid\ tracks what kind of page grid we are in.
-%
-% Note: Access \cmd\thepagegrid\ only within the safety of the output routine.
-%
-% Warning: The page grid should be changed only within the safety of the output routine.
-% People who write multicol page grid mechanisms appear not to understand the matter, so they
-% should particularly heed this warning. Think about it: obviously Lamport did so, which is why
-% his \cmd\twocolumn\ command forced a pagebreak, which is limiting, but safe.
-%    \begin{macrocode}
-\def\thepagegrid{one}%
-%    \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{Application Note: implementing a page grid}
-%
-% If you want to create a new page grid for \LaTeX,
-% you must define five procedures with specific names:
-% \cmd\open@column@ name, \cmd\shut@column@ name, \cmd\end@column@ name,
-% \cmd\output@column@ name, and \cmd\@addmarginpar@ name, where ``name'' is the 
-% name of your page grid.
-%
-% The procedure \cmd\open@column@ name starts the new page grid. It should define \cmd\thepagegrid,
-% deal with \cmd\box\cmd\pagesofar\ and \cmd\box\cmd\footsofar\ (perhaps by leaving them alone),
-% and it should set the values of \LaTeX's page layout parameters for the column size and height.
-%
-% The procedure \cmd\shut@column@ name should expect to be called with \cmd\holdinginserts\
-% cleared (it can assume that \cmd\holdinginserts\ will automatically be restored).
-% It should properly deal with insertions (like footnotes); calling \cmd\@makecolumn\
-% with an argument of \cmd\false@sw\ will do this.
-% It should know that the page grid is being terminated
-% in the middle of a page, so it should make arrangements to carry the footnotes down to the 
-% bottom of the column or page, and it should possibly salt away the material for later
-% incorporation into the page. The box registers \cmd\footsofar\ and \cmd\pagesofar\ are customarily used 
-% for this purpose.
-%
-% The procedure \cmd\end@column@ name should kick out a possibly short page containing all the 
-% floats committed to the page. It will be invoked during \cmd\clearpage\ processing.
-% After that, it should \cmd\unvbox\cmd\@cclv.
-%
-% The procedure \cmd\output@column@ name should ship out or commit the current \cmd\@outputbox.
-% In a one-column layout, you ship out; in a multicolumn layout, you commit the box as the contents
-% of a particular column, and if that column is the last, you ship out.
-%
-% The procedure \cmd\@addmarginpar@ name should return a boolean (either \cmd\true@sw\ or \cmd\false@sw\ or an equivalent)
-% to tell the marginpar mechanism to place the marginal material to the right or left, respectively.
-%
-% You can use the existing page grids ``one'' and ``mlt'' as a point of departure for creating others.
-% The former can be the basis for, say, a single-column page grid with a side column.
-%
-% \begin{macro}{\pagesofar}
-% \begin{macro}{\footsofar}
-% The box register \cmd\pagesofar\ holds the portion of the (full-width) page that is already composed into columns. 
-% This, plus the finished columns, each with its floats, plus \cmd\box255 constitute the full galley.
-%
-% The box register \cmd\footsofar\ holds all of the footnotes associated with \cmd\pagesofar.
-%    \begin{macrocode}
-\newbox\pagesofar
-\newbox\footsofar
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\combine@foot@inserts}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-% The procedure \cmd\combine@foot@inserts\ is for the purpose of merging 
-% the recently contributed footnotes (usually \cmd\box\cmd\footins)
-% with those saved from earlier on the page (usually \cmd\box\cmd\footsofar). 
-%
-% It is employed in a number of circumstances. 
-%
-% \cmd\@makecolumn (when its argument is \cmd\false@sw): 
-% we are not shipping out, so we need to salt away any footnotes there may be. 
-% 
-% \cmd\shut@column@one: we are leaving the one-column page grid, so recover the footnotes from that material
-% and combine them with those of \cmd\pagesofar. 
-%
-% \expandafter\cmd\csname balance@2\endcsname: two columns of type have been balanced, so now balance the footnotes. 
-% The \cmd\combine@foot@inserts\ procedure is first used to gather footnotes from the columns balanced with those of \cmd\pagesofar. 
-%
-% Bug 571 note: if balancing a two-column page grid, and there had been footnotes in the \cmd\pagesofar, 
-% those footnotes will have been balanced into a page-width box, \cmd\box\cmd\footsofar. 
-% We need to now re-cast them into a single, column-width galley, and only then 
-% combine them with those in \cmd\box\cmd\footins. 
-% 
-%    \begin{macrocode}
-\def\combine@foot@inserts#1#2{%
-  \ltxgrid@info@sw{\class@info{\string\combine@foot@inserts\string#1\string#2}}{}%
-  \@ifvoid#1{%
-    \ltxgrid@foot@info@sw{\trace@box#2}{}\global\setbox#1\box#2%
-  }{%
-   \global\setbox#1\vbox\bgroup
-    \ltxgrid@foot@info@sw{\trace@box#1}{}\unvbox#1%
-    \@ifvoid#2{}{%
-     \marry@baselines
-     \ltxgrid@foot@info@sw{\trace@box#2}{}\unvbox#2%
-    }%
-   \egroup
-  }%
-  \ltxgrid@foot@info@sw{\trace@scroll{\showbox#1\showbox#2}}{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-%
-% \subsubsection{One-column page grid}
-%
-% \begin{macro}{\onecolumngrid}
-% \begin{macro}{\open@column@one}
-% \begin{macro}{\shut@column@one}
-% \begin{macro}{\float@column@one}
-% \begin{macro}{\end@column@one}
-% \begin{macro}{\output@column@one}
-% \begin{macro}{\@addmarginpar@one}
-% Here are all the procedures necessary for the standard page grid named ``one'':
-% a single column layout. It is, of course, \LaTeX's familiar \cmd\onecolumn\ layout.
-% We begin with the procedure exposed to the style writer.
-% This is, however, not a \LaTeX\ command; users should not change the page grid.
-%    \begin{macrocode}
-\newcommand\onecolumngrid{\do@columngrid{one}{\@ne}}%
-%    \end{macrocode}
-%
-% Note that a document class that issues the command \cmd\onecolumn\ will break. This includes
-% \LaTeX's standard classes.dtx-based classes: if your class descends from one of these, you
-% must expunge it of all such commands.
-%    \begin{macrocode}
-\let\onecolumn\@undefined
-%    \end{macrocode}
-%
-% The procedure \cmd\open@column@one\ takes advantage of the special nature of the one-column
-% page grid to deal with \cmd\box\cmd\pagesofar, therefore it must also reset \cmd\@colroom.
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\open@column@one#1{%
- \ltxgrid@info@sw{\class@info{\string\open@column@one\string#1}}{}%
-%    \end{macrocode}
-% Throw the \cmd\pagesofar\ back onto the Main Vertical List. 
-% At this point, we must also \cmd\insert\ the footnotes back into the MVL. 
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-%    \begin{macrocode}
- \unvbox\pagesofar
- \@ifvoid{\footsofar}{}{%
-  \insert\footins\bgroup\unvbox\footsofar\egroup
-  \penalty\z@
- }%
-%    \end{macrocode}
-% Record which page grid we are using. Then calculate the set width (\cmd\hsize) and the goal height (\cmd\vsize).
-%
-% Klootch: we set the \cmd\count\cmd\footins\ to a magic number. This is only correct in the case of a two-column document.
-%    \begin{macrocode}
- \gdef\thepagegrid{one}%
- \global\pagegrid@col#1%
- \global\pagegrid@cur\@ne
- \global\count\footins\@m
- \global\divide\count\footins\tw@
- \set@column@hsize\pagegrid@col
- \set@colht
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\shut@column@one\ saves away the one-column material into the box register \cmd\pagesofar.
-% Because it is called from a message handler, we are assured that marks are properly taken care of.
-%
-% This instance of \cmd\@makecolumn\ is building a column for saving into \cmd\pagesofar.
-% \changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-% \changes{4.1f}{2009/07/15}{(AO, 519) Preserve footnotes that are in \cs{footsofar} across a page grid change}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-% We recover the footnotes into \cmd\footsofar\ (globally) and the column into \cmd\pagesofar\ (also globally), voiding \cmd\@outputbox\ by side effect. 
-%    \begin{macrocode}
-\def\shut@column@one{%
- \ltxgrid@info@sw{\class@info{\string\shut@column@one}}{}%
- \@makecolumn\false@sw
-%    \end{macrocode}
-% Split text portion of \cmd\@outputbox\ into \cmd\pagesofar,
-% and add its footnote portion to \cmd\footsofar.
-% Then void out \cmd\@outputbox.
-%    \begin{macrocode}
- \global\setbox\pagesofar\vbox\bgroup
-  \recover@column\@outputbox\footsofar\column@recovered\footins@recovered
- \egroup
- \begingroup\setbox\z@\box\@outputbox\endgroup
-%    \end{macrocode}
-% FIXME: is \cmd\combine@foot@inserts\ needed?
-% Also: if this procedure is immediately followed by \cmd\open@column@ \texttt{grid}, then \cmd\set@colht\ will be unneeded.
-%    \begin{macrocode}
- \combine@foot@inserts\footsofar\footins
- \set@colht
-}%
-%    \end{macrocode}
-%
-%FIXME: the first line of a footnote should have an up-strut, and the last line a down-strut, so that they can marry baselines.
-% The latter is the case; how about the former?
-%
-% The procedure \cmd\float@column@one\ takes care of a float column that has been built by 
-% \cmd\@tryfcolumn, in the single-column page grid.
-%
-% This instance of \cmd\@makecolumn\ is followed by \cmd\@outputpage: it is building 
-% a column for \cmd\shipout, rather than for saving into \cmd\pagesofar.
-% \changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-%    \begin{macrocode}
-\def\float@column@one{%
- \@makecolumn\true@sw
- \@outputpage
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\end@column@one\ is executed at the end of \cmd\clearpage\ processing,
-% if we were in a one-column page grid, once all permissive float pages have been shipped out.
-% At this point, one could perhaps
-% assume that nothing more need be done, but let us anyway test for committed floats and force a shipout.
-%
-% FIXME: this procedure does the same as \cmd\end@column@mlt 
-% (except for the test of \cmd\@ifx@empty\cmd\@dbltoplist):
-% the two could almost be the same procedure.
-%
-% I have changed this procedure to avoid the testing it once did: it simply puts down interrupts,
-% upon which it relies to correctly do what \cmd\clearpage\ requires.
-%    \begin{macrocode}
-\def\end@column@one{%
- \unvbox\@cclv\remove@lastbox
- \protect@penalty\do@newpage@pen
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\output@column@one\ is dispatched from the output routine when
-% we have completed a page (that is, a column in a one-column page grid);
-% it ships out the page using the \cmd\@outputpage.
-% It will be followed up with an output routine message to prepare a new column.
-%
-% Query: by what mechanism do the footnotes get placed onto such a page?
-%    \begin{macrocode}
-\def\output@column@one{%
- \@outputpage
-}%
-%    \end{macrocode}
-%
-% The following procedure determines which side of the page a marginpar will appear.
-% It reproduces the behavior of standard \LaTeX.
-%    \begin{macrocode}
-\def\@addmarginpar@one{%
- \@if@sw\if@mparswitch\fi{%
-  \@ifodd\c@page{\false@sw}{\true@sw}%
- }{\false@sw}{%
-  \@if@sw\if@reversemargin\fi{\false@sw}{\true@sw}%
- }{%
-  \@if@sw\if@reversemargin\fi{\true@sw}{\false@sw}%
- }%
-}%
-%    \end{macrocode}
-%
-% The following procedure yields a Boolean value; it determines whether a float in the deferred queue
-% is appropriate for placing. In the one-column grid, all floats are so.
-%    \begin{macrocode}
-\def\@floatselect@sw@one#1{\true@sw}%
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-\def\onecolumngrid@push{%
- \do@output@MVL{%
-  \@ifnum{\pagegrid@col=\@ne}{%
-   \global\let\restorecolumngrid\@empty
-  }{%
-   \xdef\restorecolumngrid{%
-    \noexpand\start@column{\thepagegrid}{\the\pagegrid@col}%
-   }%
-   \start@column{one}{\@ne}%
-  }%
- }%
-}%
-\def\onecolumngrid@pop{%
- \do@output@MVL{\restorecolumngrid}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsubsection{Two-column page grid}
-%
-% \begin{macro}{\twocolumngrid}
-% \begin{macro}{\open@column@mlt}
-% \begin{macro}{\shut@column@mlt}
-% \begin{macro}{\end@column@mlt}
-% \begin{macro}{\output@column@mlt}
-% \begin{macro}{\@addmarginpar@mlt}
-% \begin{macro}{\set@footnotewidth@mlt}
-% \begin{macro}{\set@footnotewidth@two}
-% \begin{macro}{\compose@footnotes@two}
-% Here are all the procedures necessary for the standard page grid named ``mlt'':
-% the multi-column page grid. With an argument of "2", it is,
-% of course, \LaTeX's familiar \cmd\twocolumn\ layout.
-%
-% We start with the procedure to switch to the two-column page grid.
-%    \begin{macrocode}
-\newcommand\twocolumngrid{\do@columngrid{mlt}{\tw@}}%
-%    \end{macrocode}
-%
-% The corresponding command of \LaTeX\ is obsolete.
-%    \begin{macrocode}
-\let\twocolumn\@undefined
-%    \end{macrocode}
-%
-% Of course, \cmd\@topnewpage\ is also obsolete. Just do 
-%\begin{quote}
-% \cmd\clearpage\cmd\onecolumngrid<vertical mode material>\cmd\twocolumngrid.
-%\end{quote}
-%    \begin{macrocode}
-\let\@topnewpage\@undefined
-%    \end{macrocode}
-%
-% If your document class descends from one of \LaTeX's standard classes.dtx-derived
-% classes, it will break. You must expunge from it all such commands.
-% 
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-%
-% Bug 571 note: it is not enough to have the \cmd\pagesofar, we must also deal with the \cmd\footsofar.
-% At this juncture, we should treat the case where the document has an essentially two-column page grid, 
-% with occasional excursions into the one-column grid. 
-% If a footnote is set within the latter grid, its set width should be that of the two-column grid. 
-%
-% When a page is shipped out, if we are currently in a one-column grid, we will compose the footnotes onto the page
-% in the form of balanced columns. This is only one way to handle footnotes: \classname{multicol}
-% appears to set footnotes on the full text width.
-%    \begin{macrocode}
-\def\open@column@mlt#1{%
- \ltxgrid@info@sw{\class@info{\string\open@column@mlt\string#1}}{}%
-%    \end{macrocode}
-% At this point, we must \cmd\insert\ the footnotes back into the Main Vertical List.
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-%    \begin{macrocode}
- \@ifvoid{\footsofar}{}{%
-  \insert\footins\bgroup\unvbox\footsofar\egroup
- }%
-%    \end{macrocode}
-% Record which page grid we are using. Then calculate the set width (\cmd\hsize) and the goal height (\cmd\vsize).
-%
-% Klootch: we set the \cmd\count\cmd\footins\ to a magic number. This value is valid whether footnotes are being
-% set on the column width or the full text width. 
-%    \begin{macrocode}
- \gdef\thepagegrid{mlt}%
- \global\pagegrid@col#1%
- \global\pagegrid@cur\@ne
- \global\count\footins\@m
- \set@column@hsize\pagegrid@col
- \set@colht
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\shut@column@mlt\ ends the current column, balances the columns, and
-% salts away all in \cmd\pagesofar. Because it is called in a message handler,
-% we are assured that marks are handled properly.
-% Attention: because this procedure balances columns, all footnotes are
-% held aside in \cmd\footsofar\ for placement at the bottom of the page.
-%
-% Bug note: the last macro executed by this procedure is \cmd\set@colht, 
-% but had been erroneously \cmd\set@colroom.
-% I now believe that the latter should be changed pretty much everywhere to the former.
-%
-% This instance of \cmd\@makecolumn\ is building material for \cmd\pagesofar, rather than 
-% for \cmd\shipout.
-% \changes{4.1b}{2008/08/04}{Change \cs{@makecol} to \cs{@makecolumn} with argument}
-% \changes{4.1b}{2008/08/04}{Change \cs{@combinepage} to \cs{@combinepage} with argument}
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-%    \begin{macrocode}
-\def\shut@column@mlt{%
- \ltxgrid@info@sw{\class@info{\string\shut@column@mlt}}{}%
- \@cclv@nontrivial@sw{%
-  \@makecolumn\false@sw
-  \@ifnum{\pagegrid@cur<\pagegrid@col}{%
-   \expandafter\global\expandafter\setbox\csname col@\the\pagegrid@cur\endcsname\box\@outputbox
-   \global\advance\pagegrid@cur\@ne
-  }{}%
- }{%
-  \void@cclv
- }%
- \@ifnum{\pagegrid@cur>\@ne}{%
-  \csname balance@\the\pagegrid@col\endcsname
-  \grid@column\@outputbox{}%
-  \@combinepage\false@sw
-  \@combinedblfloats
-  \global\setbox\pagesofar\box\@outputbox
-  \show@pagesofar@size
- }{}%
- \set@colht
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\float@column@mlt\ takes care of a float page that has been built by \cmd\@tryfcolumn,
-% in the multi-column page grid. It is coincidentally identical to what happens in 
-% \cmd\do@startpage\ when a page needs to be shipped out.
-% \changes{4.1b}{2008/08/04}{New procedure \cs{@output@combined@page}}
-%    \begin{macrocode}
-\def\float@column@mlt{%
-  \@output@combined@page
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\end@column@mlt\ is executed at the end of \cmd\clearpage\ processing,
-% if we were in a multi-column page grid, once all permissive float pages have been shipped out.
-% If no floats are committed and if no columns are yet filled, we have nothing to do.
-% Otherwise, we kick out a column and try again.
-%
-% Note that in our code to kick out a column, we must deal properly with the case where the column
-% is trivial: it will have nothing but \cmd\topskip\ glue plus a protection box. We substitute an ordinary
-% \cmd\null\ for the protection box.
-% 
-%    \begin{macrocode}
-\def\end@column@mlt{%
- \@ifx@empty\@toplist{%
-  \@ifx@empty\@botlist{%
-   \@ifx@empty\@dbltoplist{%
-    \@ifx@empty\@deferlist{%
-     \@ifnum{\pagegrid@cur=\@ne}{%
-      \false@sw
-     }{%
-      \true@sw
-     }%
-    }{%
-     \true@sw
-    }%
-   }{%
-    \true@sw
-   }%
-  }{%
-   \true@sw
-  }%
- }{%
-  \true@sw
- }%
- % true = kick out a column and try again
- {%
-  \@cclv@nontrivial@sw{%
-   \unvbox\@cclv\remove@lastbox
-  }{%
-   \unvbox\@cclv\remove@lastbox\unskip\null
-  }%
-  \protect@penalty\do@newpage@pen
-  \protect@penalty\do@endpage@pen
- }{%
-  \unvbox\@cclv\remove@lastbox
- }%
-}%
-%    \end{macrocode}
-%
-% The procedure \cmd\output@column@mlt (cf. \cmd\output@column@one)
-% is dispatched from the output routine when
-% we have completed a column in a multi-column page grid).
-% (It replaces the \cmd\@outputdblcol\ of standard \LaTeX.)
-% If a complete set of columns is at hand, it ships out the page and 
-% lays down an interrupt for \cmd\do@startpage@pen, which will commit the 
-% full-page-width floats to the next page.
-% Like \cmd\output@column@mlt, this is followed by
-% an output routine message to prepare a new column.
-%
-% If a page needs to be shipped out, it uses the same mechanism as \cmd\do@startpage.
-% \changes{4.1b}{2008/08/04}{New procedure \cs{@output@combined@page}}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-%    \begin{macrocode}
-\def\output@column@mlt{%
- \@ifnum{\pagegrid@cur<\pagegrid@col}{%
-  \expandafter\global\expandafter\setbox\csname col@\the\pagegrid@cur\endcsname\box\@outputbox
-  \global\advance\pagegrid@cur\@ne
- }{%
-  \set@adj@colht\dimen@
-  \grid@column\@outputbox{}%
-  \@output@combined@page
- }%
-}%
-%    \end{macrocode}
-% The procedure \cmd\output@column@mlt\ obsoletes \LaTeX's \cmd\@outputdblcol
-%    \begin{macrocode}
-\let\@outputdblcol\@undefined
-%    \end{macrocode}
-%
-% The following procedure yields a Boolean value; it determines whether a float in the deferred queue
-% is appropriate for placement in the column. In the multi-column grid, only those narrower than \cmd\textwidth\ are so.
-%    \begin{macrocode}
-\def\@floatselect@sw@mlt#1{\@if@notdblfloat{#1}}%
-%    \end{macrocode}
-%
-% The following procedure determines which side of the page a marginpar will appear.
-% It reproduces the behavior of standard \LaTeX.
-%    \begin{macrocode}
-\def\@addmarginpar@mlt{% emits a boolean
- \@ifnum{\pagegrid@cur=\@ne}%
-}%
-%    \end{macrocode}
-%
-% \cmd\set@footnotewidth@one\ sets the width of type within footnotes to span the full text width; 
-% \cmd\set@footnotewidth@two\ to span a single column of the two-column grid, and 
-% more generally \cmd\set@footnotewidth@mlt\ for a multi-column page grid. 
-%    \begin{macrocode}
-\def\set@footnotewidth@one{%
- \hsize\columnwidth
- \linewidth\hsize
-}%
-\def\set@footnotewidth@two{\set@footnotewidth@mlt\tw@}%
-\def\set@footnotewidth@mlt#1{%
- \hsize\textwidth
- \advance\hsize\columnsep
- \divide\hsize#1%
- \advance\hsize-\columnsep
- \linewidth\hsize
-}%
-%    \end{macrocode}
-%
-% \cmd\compose@footnotes\ is the procedure for arranging the footnotes for
-% placement at the bottom of the page or column. 
-% In the former case, the material will be shipped out; in the latter, we must allow
-% the column to possibly be balanced later on. 
-%
-% \cmd\compose@footnotes@one\ is a no-op, because the footnotes require no rearrangement. 
-% In a scheme where footnotes are set on the full text width, this would be the procedure called. 
-%
-% \cmd\compose@footnotes@two\ implements the case where a two-column document has been interrupted
-% with full-page-width text (e.g., the widetext environment or the end of the document), 
-% and a natural page break appears. 
-%
-% In either case, we assume that argument \verb+#1+ is an \cmd\insert\  register and must be assigned globally,
-% so that when it is accessed with \cmd\box\ or \cmd\unvbox, it will be voided globally as well. 
-% 
-% To extend this scheme to a three-column page grid \cmd\compose@footnotes@thr@@\ would be created:
-% it would balance the saved up footnotes into three columns. 
-%
-%    \begin{macrocode}
-\def\compose@footnotes@one#1{%
- \ltxgrid@foot@info@sw{\class@info{\string\compose@footnotes@one\string#1}\trace@box#1}{}%
-}%
-\let\compose@footnotes\compose@footnotes@one
-\def\compose@footnotes@two#1{%
- \ltxgrid@foot@info@sw{\class@info{\string\compose@footnotes@two\string#1}\trace@box#1}{}%
- \setbox\z@\box\@tempboxa
- \let\recover@column\recover@column@null
- \let\marry@baselines\@empty
- \balance@two#1\@tempboxa
- \global\setbox#1\hbox to\textwidth{\box#1\hfil\box\@tempboxa}%
- \ltxgrid@foot@info@sw{\trace@box#1}{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsubsection{Page grid utility procedures}
-%
-% \begin{macro}{\pagegrid@cur}
-% \begin{macro}{\pagegrid@col}
-% \begin{macro}{\pagegrid@init}
-% We take over \LaTeX's \cmd\col@number, and \cmd\@leftcolumn, which are obsolete (\cmd\@holdpg\ could also be taken over). 
-% We create two counters to hold the columns in the page grid and the current column within.
-% We also create the first of a set of box registers to hold the committted columns.
-%    \begin{macrocode}
-\let\pagegrid@cur\col@number
-\let\col@number\@undefined
-\newcount\pagegrid@col
-\pagegrid@cur\@ne
-\expandafter\let\csname col@\the\pagegrid@cur\endcsname\@leftcolumn
-\let\@leftcolumn\@undefined
-%    \end{macrocode}
-%
-% The default is for maximum two columns.
-% If your class will require more columns, assign that number to \cmd\pagegrid@col\
-% before \envb{document} time.
-%    \begin{macrocode}
-\pagegrid@col\tw@
-%    \end{macrocode}
-%
-% The procedure \cmd\pagegrid@init\ is a loop, exercising \cmd\newbox\ sufficiently to create the 
-% boxes for holding the columns in the page grid; these have names like \expandafter\cmd\csname col@1\endcsname, etc. 
-%    \begin{macrocode}
-\def\pagegrid@init{%
- \advance\pagegrid@cur\@ne
- \@ifnum{\pagegrid@cur<\pagegrid@col}{%
-  \csname newbox\expandafter\endcsname\csname  col@\the\pagegrid@cur\endcsname
-  \pagegrid@init
- }{%
- }%
-}%
-\appdef\class@documenthook{%
- \pagegrid@init
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\grid@column}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-% The procedure \cmd\grid@column\ knows how to lay up the columns in a multi-column page grid.
-% It uses utility procedures \cmd\append@column@\ and \cmd\box@column.
-%
-% The first argument is the box register to create, usually \cmd\@outputbox, and provides both input and output. 
-% The second argument a dimension, allowing us to strut down the depth of the box we create. 
-%
-%    \begin{macrocode}
-\def\grid@column#1#2{%
- \ltxgrid@info@sw{\class@info{\string\grid@column\string#1}}{}%
- \global\setbox#1\vbox\bgroup
-  \hb@xt@\textwidth\bgroup
-   \vrule\@height\z@\@width\z@\@if@empty{#2}{}{\@depth#2}%
-   \pagegrid@cur\@ne
-   \@ifnum{\pagegrid@cur<\pagegrid@col}{\loopwhile{\append@column@\pagegrid@cur\pagegrid@col}}{}%
-   \box@column#1%
-  \egroup
-%    \end{macrocode}
-% FIXME: page depth!
-%    \begin{macrocode}
-  \vskip\z@skip
- \egroup
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\append@column@}
-% \begin{macro}{\box@column}
-% \begin{macro}{\marry@baselines}
-% The procedure \cmd\append@column@\ appends columns for \cmd\grid@column,
-% \cmd\box@column\ builds the columns for \cmd\append@column@,
-% and \cmd\marry@baselines\ pastes vertical things back together.
-% \changes{4.0a}{2001/06/18}{Introduce \cs{marry@height} }
-%
-% Note that \cmd\box@column\ makes an attempt to prevent excessive \cmd\topskip\
-% or \cmd\baselineskip\ glue
-% from being applied by \TeX\ when \cmd\@outputbox\ is contributed to the MVL.
-% If this is not done, it is possible to get into an infinite loop in the corner case,
-% wherein the page grid is changed to one column and the balanced-up columns are
-% already sufficient to fill the page.
-%
-% Note (AO 0920):  I have changed the dimension involved with \cmd\box@column\ from
-% \cmd\vsize\ to \cmd\textheight, because the former is certainly not the correct value
-% to use: it will change if floats have been placed in the last column of the page.
-% I believe \cmd\textheight\ is the correct parameter to use here.
-%
-% A REVTeX4 user, Sergey Strelkov (strelkov@maik.rssi.ru), wants the option
-% of ragged-bottom columns. Implementing this feature properly means reboxing the 
-% columns to their natural height only if \cmd\raggedcolumn@sw\ is true.
-% Otherwise, they get reboxed to their common height (\cmd\@colht?).
-%
-% Note that the default has hereby changed from ragged to flush. 
-% It's not clear that anyone but Sergey will notice.
-%
-% The macro \cmd\marry@skip\  addresses (in a limited way)
-% the fact that neither the value of \cmd\baselineskip\ nor that of \cmd\topskip\
-% can be relied upon for the purpose of marrying the baselines of two split columns.
-% (Because there might have been a local change to their values at the point where
-% the output routine got triggered.)
-%
-% For best results, your document class should call for grid changes only when in basal text
-% settings. The \cmd\marry@baselines\ procedure will use the values appropriate to that point
-% when attempting to put the columns back together.
-%
-% In any case, we are not attempting to solve the more general problem of how to marry baselines
-% where the leading can change arbitrarily within the galley or where glue could have been trimmed
-% at a page top.
-%
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-% Procedure \cmd\append@column@\ composes a column onto the horizontal list along with its \cmd\columnseprule. 
-% Its arguments are: \verb+#1+---\cmd\pagegrid@cur, and \verb+#2+---\cmd\pagegrid@col
-%    \begin{macrocode}
-\def\append@column@#1#2{%
- \expandafter\box@column\csname col@\the#1\endcsname
- \hfil\vrule\@width\columnseprule\hfil
- \advance#1\@ne
-%    \end{macrocode}
-% This procedure is the argument of \cmd\loopwhile, so it must leave a Boolean (e.g., \cmd\true@sw) in \TeX's scanner. 
-%    \begin{macrocode}
- \@ifnum{#1<#2}%
-}%
-%    \end{macrocode}
-% \changes{4.1n}{2010/01/02}{(AO, 571) calling sequence of \cs{combine@foot@inserts} and \cs{grid@column} to expose box registers; that of \cs{append@column@} its column counters}%
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-% Procdure \cmd\box@column, used by \cmd\append@column@, puts down a box containing the specified column.
-% Its height is adjusted down to \cmd\@colht, if needed; likewise, the width is set to \cmd\columnwidth. 
-% The rag at the bottom is controlled by \cmd\raggedcolumn@skip. 
-%    \begin{macrocode}
-\def\box@column#1{%
- \ltxgrid@info@sw{\class@info{\string\box@column\string#1}}{}%
- \raise\topskip
- \hb@xt@\columnwidth\bgroup
-  \dimen@\ht#1\@ifdim{\dimen@>\@colht}{\dimen@\@colht}{}%
-  \count@\vbadness\vbadness\@M
-  \dimen@ii\vfuzz\vfuzz\maxdimen
-  \ltxgrid@info@sw{\saythe\@colht\saythe\dimen@}{}%
-  \vtop to\dimen@\bgroup
-   \hrule\@height\z@
-   \unvbox#1%
-   \raggedcolumn@skip
-  \egroup
-  \vfuzz\dimen@ii
-  \vbadness\count@
-  \hss
- \egroup
-}%
-%    \end{macrocode}
-% The purpose of procedure \cmd\marry@baselines\ is to ensure that the baseline spacing is correct; 
-% it does this by making adjustments to the previous line, compensating for its depth, and by adding in 
-% skip glue in an amount that assumes the added material has \cmd\topskip\ glue above. 
-%    \begin{macrocode}
-\def\marry@baselines{%
- \begingroup
-  \setbox\z@\lastbox
-  \@ifvoid{\z@}{%
-   \endgroup
-  }{%
-   \aftergroup\kern
-   \aftergroup-%
-   \expandafter\box\expandafter\z@\expandafter\endgroup\the\dp\z@\relax
-  }%
- \vskip\marry@skip\relax
-}%
-\gdef\marry@skip{\z@skip}%
-\def\set@marry@skip{%
- \begingroup
-  \skip@\baselineskip\advance\skip@-\topskip
-  \@ifdim{\skip@>\z@}{%
-   \xdef\marry@skip{\the\skip@}%
-  }{}%
- \endgroup
-}%
-%    \end{macrocode}
-% \changes{4.1b}{2008/08/04}{Use \cs{document@inithook} instead of \cs{AtBeginDocument}}
-%    \begin{macrocode}
-\appdef\document@inithook{%
- \@ifxundefined\raggedcolumn@sw{\@booleanfalse\raggedcolumn@sw}{}%
-}%
-\def\raggedcolumn@skip{%
- \vskip\z@\raggedcolumn@sw{\@plus.0001fil\@minus.0001fil}{}\relax
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@combinepage}
-% The procedure \cmd\@combinepage\ prepends the stored page (\cmd\pagesofar) to \cmd\@outputbox\ and
-% employs \cmd\@combineinserts\ to lay down the footnotes. 
-% The next event will usually be shipping out the made-up page, but not always. 
-% Therefore the argument of \cmd\@combinepage, which must be a Boolean, determines
-% if the footnotes are to be combined into this page.
-% 
-% \changes{4.1b}{2008/08/04}{Change \cs{@combinepage} to \cs{@combinepage} with argument}
-% \changes{4.1b}{2008/08/04}{(AO, 452) Support length checking: show size of shipped out text.}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%
-% QUERY: In the following, if \cmd\box\cmd\footins\ is not void, its contents are lost. Can this ever happen?
-%    \begin{macrocode}
-\def\@combinepage#1{%
- \ltxgrid@foot@info@sw{\class@info{\string\@combinepage\string#1}}{}%
- \@ifvoid\pagesofar{}{%
-  \setbox\@outputbox\vbox{%
-   \unvbox\pagesofar
-   \marry@baselines
-   \unvbox\@outputbox
-  }%
- }%
- #1{%
-  \@ifvoid\footsofar{}{%
-%    \end{macrocode}
-% At this point, \cmd\footins\ is empty; all of the footnotes have been combined into \cmd\footsofar.
-%    \begin{macrocode}
-   \show@box@size{Combining page footnotes}\footsofar
-   \setbox\footins\box\footsofar
-%    \end{macrocode}
-% Depending on the page grid, we compose the footnotes for placement on the page. 
-%    \begin{macrocode}
-   \compose@footnotes
-   \@combineinserts\@outputbox\footins
-  }%
- }{%
-%    \end{macrocode}
-%QUERY: The following line was removed, probably to fix a bug. When was this done?
-%    \begin{verbatim}
-% \global\setbox\footins\box\footsofar
-%    \end{verbatim}
-%    \begin{macrocode}
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@cflt}
-% \begin{macro}{\@cflb}
-% \changes{4.1b}{2008/08/04}{}
-% We modify \LaTeX's \cmd\@cflt\ and \cmd\@cflb\ to remove the unwanted glue with \cmd\unskip.
-%    \begin{macrocode}
-\def \@cflt{%
- \let \@elt \@comflelt
- \setbox\@tempboxa \vbox{}%
- \@toplist
- \setbox\@outputbox \vbox{%
-  \boxmaxdepth \maxdepth
-  \unvbox\@tempboxa\unskip
-  \topfigrule\vskip \textfloatsep
-  \unvbox\@outputbox
- }%
- \let\@elt\relax
- \xdef\@freelist{\@freelist\@toplist}%
- \global\let\@toplist\@empty
-}%
-\def \@cflb {%
- \let\@elt\@comflelt
- \setbox\@tempboxa \vbox{}%
- \@botlist
- \setbox\@outputbox \vbox{%
-  \unvbox\@outputbox
-  \vskip \textfloatsep\botfigrule
-  \unvbox\@tempboxa\unskip
- }%
- \let\@elt\relax
- \xdef\@freelist{\@freelist\@botlist}%
- \global \let \@botlist\@empty
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@combinedblfloats}
-% We modify \LaTeX's \cmd\@combinedblfloats\ to be more appropriate for incremental page building:
-% we \cmd\unvbox\ the \cmd\@outputbox.
-%    \begin{macrocode}
-\def\@combinedblfloats{%
- \@ifx@empty\@dbltoplist{}{%
-  \setbox\@tempboxa\vbox{}%
-  \let\@elt\@comdblflelt\@dbltoplist
-  \let\@elt\relax\xdef\@freelist{\@freelist\@dbltoplist}%
-  \global\let\@dbltoplist\@empty
-  \setbox\@outputbox\vbox{%
-   %\boxmaxdepth\maxdepth   %% probably not needed, CAR
-   \unvbox\@tempboxa\unskip
-   \@ifnum{\@dbltopnum>\m@ne}{\dblfigrule}{}%FIXME: how is \@dbltopnum maintained?
-   \vskip\dbltextfloatsep
-   \unvbox\@outputbox
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\set@column@hsize}%
-% The procedure \cmd\set@column@hsize\ takes care of setting up the horizontal dimensions
-% for the current page grid. The present routine will certainly not be adequate for more
-% complex page layouts (e.g., with a side column), but works for the common ones.
-% \changes{4.0a}{2001/06/18}{Introduce \cs{set@marry@height} }
-%    \begin{macrocode}
-\def\set@column@hsize#1{%
- \pagegrid@col#1%
- \global\columnwidth\textwidth
- \global\advance\columnwidth\columnsep
- \global\divide\columnwidth\pagegrid@col
- \global\advance\columnwidth-\columnsep
- \global\hsize\columnwidth
- \global\linewidth\columnwidth
- \skip@\baselineskip\advance\skip@-\topskip
- \@ifnum{\pagegrid@col>\@ne}{\set@marry@skip}{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\set@colht}%
-% \begin{macro}{\set@colroom}%
-% \begin{macro}{\set@vsize}%
-% \begin{macro}{\set@adj@colht}%
-% The story of \cmd\textheight, \cmd\@colht, \cmd\@colroom, and \cmd\vsize.
-%
-% \cmd\textheight---height of the text column. Not a running parameter, however, each time a page is 
-% shipped out, the \cmd\textheight\ could in principle be altered. This must be done before
-%
-% \cmd\@colht---\cmd\textheight\ minus the height of any full-page-width floats. The latter are committed
-% only just after shipping out, and only if we are in a multicolumn page grid.
-% Therefore, \cmd\@colht\ should be set after a \cmd\shipout\ (by \cmd\@outputpage) and
-% will be adjusted when full-page-width floats are committed to the fresh page by \cmd\do@startpage.
-%
-% \cmd\@colroom---\cmd\@colht\ (adjusted by \cmd\pagesofar) minus the height of any column-width floats.
-% The latter are committed anywhere on the page, at which point \cmd\@colroom\ must be adjusted.
-% Therefore, \cmd\@colroom\ should be set (by \cmd\set@colroom) whenever a column is prepared (by ).
-%FIXME: committed (by \cmd\output@column@) and
-% will be adjusted (by \cmd\@add@float\ or \cmd\do@startcolumn) whenever a float is committted to the column.
-%
-% \cmd\vsize---\cmd\@colroom.
-% Therefore, \cmd\vsize\ should be set (by \cmd\set@vsize) whenever
-% the \cmd\@colroom\ is set (by \cmd\set@colroom) or adjusted (by \cmd\@add@float\ or \cmd\do@startcolumn)
-%FIXME: or when the \cmd\pagesofar\ box is changed (after invoking \cmd\open@column@).
-%
-% Question: what if there are committed floats? Footnotes?
-% Answer: full-page-width floats are only committed at top, and they are already reckoned with in \cmd\@colht.
-% Column-width committed floats are incorporated by \cmd\@makecolumn.
-%
-% As to footnotes, our scheme is to keep the \cmd\footins\ insert register up to date, and to use the insert mechanism 
-% to ensure room for footnotes. 
-% When a change is made to the page grid, the footnotes will need to be propagated back into the MVL. 
-%
-% Note: FIXME: adjusting for \cmd\pagesofar\ is done at not quite the right time. I need to reexamine \cmd\set@colht,
-% because \cmd\@dbltoplist\ and \cmd\pagesofar\ really should be on the same footing.
-% Perhaps \cmd\@colht\ and \cmd\@colroom\ should both deal with their respective ``lists'' in the same way?
-%
-% These concerns will be particularly germane if we ever extend this package to deal with full-page-width floats
-% placed at the bottom of the page, or committed on the same page as called out.
-%
-% It occurs to me that we should ditch \cmd\set@colroom\ and only ever execute \cmd\set@colht, 
-% which sets \cmd\@colroom\ as a side effect.
-% If so, we can make \cmd\@colht\ take \cmd\pagesofar\ into account, as it should. Then \cmd\@colht\ will return to its 
-% original significance as the value that \cmd\@colroom\ is set to after a column is committed.
-%
-% On the other hand, why not simply forget all this caching and (re-)calculate \cmd\vsize\ as late as possible?
-% Particularly, \cmd\@colht\ is an artifact of the old way of doing things, where once it was set, it would never change.
-% 
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\set@colht{%
- \set@adj@textheight\@colht
- \global\let\enlarge@colroom\@empty
- \set@colroom
-}%
-\def\set@adj@textheight#1{%
- \ltxgrid@info@sw{\class@info{\string\set@adj@textheight\string#1}\saythe\textheight}{}%
- #1\textheight
- \def\@elt{\adj@page#1}%
- \@booleantrue\firsttime@sw\@dbltoplist
- \let\@elt\relax
- \global#1#1\relax
- \ltxgrid@info@sw{\saythe#1}{}%
-}%
-\def\set@colroom{%
- \ltxgrid@info@sw{\class@info{\string\set@colroom}}{}%
- \set@adj@colht\@colroom
- \@if@empty\enlarge@colroom{}{%
-  \global\advance\@colroom\enlarge@colroom\relax
-  \ltxgrid@info@sw{\saythe\@colroom}{}%
- }%
- \@ifdim{\@colroom>\topskip}{}{%
-  \ltxgrid@info{Not enough room: \string\@colroom=\the\@colroom; increasing to \the\topskip}%
-  \@colroom\topskip
- }%
- \global\@colroom\@colroom
-%<ignore> \ltxgrid@info@sw{\class@info{\string\set@colroom\string\vsize=\string\colroom}\saythe\vsize}{}%
- \set@vsize
-}%
-%
-\def\set@vsize{%
- \global\vsize\@colroom
- \ltxgrid@info@sw{\class@info{\string\set@vsize\string\vsize=\string\colroom}\saythe\vsize}{}%
-}%
-%    \end{macrocode}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-%    \begin{macrocode}
-\def\set@adj@colht#1{%
- #1\@colht
- \ltxgrid@info@sw{\class@info{\string\set@adj@colht\string#1-\string\pagesofar}\saythe#1}{}%
- \@ifvoid\pagesofar{}{%
-  \advance#1-\ht\pagesofar\advance#1-\dp\pagesofar
-  \ltxgrid@info@sw{\class@info{\string\pagesofar}\saythe#1}{}%
- }%
- \def\@elt{\adj@column#1}%
- \@booleantrue\firsttime@sw\@toplist
- \@booleantrue\firsttime@sw\@botlist
- \let\@elt\relax
-}%
-\def\adj@column#1#2{%
- \advance#1-\ht#2%
- \advance#1-\firsttime@sw{\textfloatsep\@booleanfalse\firsttime@sw}{\floatsep}%
- \ltxgrid@info@sw{\class@info{\string\adj@column\string#1-\string#2}\saythe#1}{}%
-}%
-\def\adj@page#1#2{%
- \advance#1-\ht#2%
- \advance#1-\firsttime@sw{\dbltextfloatsep\@booleanfalse\firsttime@sw}{\dblfloatsep}%
- \ltxgrid@info@sw{\class@info{\string\adj@page\string#1-\string#2}\saythe#1}{}%
-}%
-\def\set@adj@box#1#2{%
- \@ifvoid#2{}{%
-  \advance#1-\ht#2\advance#1-\dp#2%
-  \@booleantrue\temp@sw
-  \ltxgrid@foot@info@sw{\class@info{\string\set@adj@box\string#2}\saythe#1}{}%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@outputpage@tail}%
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@tail} tailpatches \cs{@outputpage}}%
-% In \cmd\@outputpage@tail, we set \cmd\@colht\ and the float placement parameters
-% (this is the one point where it is appropriate to set \cmd\@colht).
-% At \cmd\do@startpage\ time, we adjust \cmd\@colht's value to reflect committed 
-% full-page-width floats.
-%
-% Note: with a correctly written output routine, a call to \cmd\@outputpage\ will inevitably be 
-% followed by a call to \cmd\do@startpage, so these procedure calls would be unneeded.
-%    \begin{macrocode}
-\appdef\@outputpage@tail{%
- \set@colht          % FIXME: needed?
- \@floatplacement    % FIXME: needed?
- \@dblfloatplacement % FIXME: needed?
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{balance@2}
-% \changes{4.1b}{2008/08/04}{Procedure \cs{balance@2} defined more transparently}%
-% We define procedures for balancing columns in a multicolumn layout.
-% For now, we define only one: a procedure for the two-column grid.
-% All others will simply \cmd\relax\ out.
-%
-% The following code defines \verb+\balance@2+ without all the clunky \cmd\csname\ commands
-% in the replacement part,
-% which appears on the right-hand side of the assignment to \cmd\toks@.
-%
-% The method is straightforward: balance the two columns of text, and balance the footnotes.
-% Later on, \cmd\@combineinserts\ will be called to place the footnotes after the now-balanced columns.
-%
-% \changes{4.1f}{2009/07/14}{(AO, 519) \cs{footins} content must be preserved and reintegrated}
-% It was necessary to deal with the case where \cmd\box\cmd\footsofar\ was not empty
-% upon execution of this balancing code. We store it away in \cmd\box\cmd\footins\ and
-% add it back in afterwards.
-%
-% Here is a conundrum: if we switch between single-, two-, and three-column page grids:
-% On what measure should the footnotes be set?
-%    \begin{macrocode}
-\begingroup
- \catcode`\1=\cat@letter
- \catcode`\2=\cat@letter
-%    \end{macrocode}
-% \cmd\toks@\ contains the repacement part for an effective \cmd\def\cs{balance@2}.
-%    \begin{macrocode}
- \toks@{%
-%    \end{macrocode}
-% \cmd\balance@two, by side effect, strips footnotes into \cmd\box\cmd\footins. 
-%    \begin{macrocode}
-  \setbox\footins\box\footsofar
-  \balance@two\col@1\@outputbox
-%    \end{macrocode}
-% We ensure that the box assignments are global. 
-%    \begin{macrocode}
-  \global\setbox\col@1\box\col@1
-  \global\setbox\@outputbox\box\@outputbox
-%    \end{macrocode}
-% The following line puts all footnotes into the footnote galley, \cmd\footsofar.
-%    \begin{macrocode}
-  \combine@foot@inserts\footsofar\footins
- }%
- \aftergroup\def\aftergroup\balance@2\expandafter
-\endgroup\expandafter{\the\toks@}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\balance@two}
-% The procedure \cmd\balance@two\ takes two columns and balances them; in the process it removes
-% any footnotes that may be present to a place of safety \cmd\footsofar, 
-% for later placement at the foot of the shipped-out page. 
-% The box register \cmd\box\cmd\@ne\ is the aggregate of all columns.
-% The box register \cmd\box\cmd \z@\ is the last column.
-% The box register \cmd\box\cmd\tw@\ is the first column.
-% The \cmd\dimen\ register \cmd\dimen@\  is the trial value to \cmd\vsplit\ to, 
-% initially half the height of \cmd\box\cmd\@ne.
-% The \cmd\dimen\ register \cmd\dimen@i\ is the increment for the next trial;
-% its initial value is equal to the initial value of \cmd\dimen@.
-% The \cmd\dimen\ register \cmd\dimen@ii\ is the difference of the heights of the two columns.
-%
-% The procedure uses a binary search for that value of \cmd\dimen@\ which is stable to within .5\cmd\p@\ and which
-% makes the last column be shorter than the others.
-%
-% This procedure can be extended to multiple columns simply by changing it to execute \cmd\vsplit\ multiple
-% times (one less than the total number of columns in the page layout) and to calculating \cmd\dimen@ii\
-% to be the difference of the heights of last column and the \cmd\dimen@.
-% Upon termination of the search, one would excute the \cmd\vsplit s once again, this time 
-% using the actual \cmd\col@\ box registers to store the 
-% balanced columns, thereby clobbering their former contents.
-%
-% Bug Note:
-% as originally written, this macro had a bug, which is well worth avoiding under similar circumstances anywhere.
-% So, learn from the mistakes of others, as they say.
-% In trying to remove the depth of the boxes created via \cmd\vsplit\ within the \cmd\loopwhile\ control,
-% I originally coded
-% \cmd\unvbox
-% \cmd\z@\
-% \cmd\setbox
-% \cmd\z@
-% \cmd\lastbox\
-% \cmd\dimen@
-% \cmd\dp
-% \cmd\z@\
-% \cmd\box
-% \cmd\z@\
-% \cmd\vskip-%
-% \cmd\dimen@.
-% The error here is that the (horizontal) shift of the last box in the vertical list will be lost in the process.
-% Simply put, \cmd\setbox\cmd\z@\cmd\lastbox\ fails to retain the shift of the box node in the vertical list,
-% and when it is put down again via \cmd\box\cmd\z@, it will no longer have the correct shift.
-%
-% This bug affected things placed in the MVL with \cmd\moveleft, \cmd\moveright, \cmd\parshape, and 
-% \cmd\hangindent, as well as things shifted by \TeX's primitive mechanisms.
-%
-% A superior strategy for removing the depth of the last line of the list is more expensive, but safer:
-% make a separate copy of the list, measure the depth of the last box as above, but then discard
-% the list, retaining only the value of the dimension.
-% 
-% Note that this procedure will not work if the material within is excessively chunky.
-% A particular failure mode exists where none of the material is allocated to the last (right) column.
-% We detect this case and revert to unbalanced columns.
-%
-% Another failure mode is where a large chunk occurs at the beginning of the composite box.
-% In this case, the left column may fill up even when \cmd\dimen@\ is very small.
-% If this configuration leaves the left column longer than the right, then we are done,
-% but \cmd\dimen@\ by  no means represents the height of either finished box.
-%
-% Therefore the last step in the process is to rebox the two columns to a common height determined
-% independently of the balancing process.
-%
-% The dimension involved is checked against the current \cmd\@colroom\ to guard against the case where
-% excessive material happens to fall in either column.
-% \changes{4.1b}{2008/08/04}{Change \cs{set@colroom} to \cs{set@colht}}
-% \changes{4.1n}{2009/12/02}{More diagnostics of column balancing}
-% \changes{4.1n}{2010/01/02}{(AO, 571) coding convention: use \cs{bgroup}, \cs{egroup} (instead of braces) when a box is being built}%
-% \changes{4.1n}{2010/01/02}{(AO, 571) Footnotes, when columns are balanced or when they are composed with their column}%
-% \changes{4.1n}{2010/01/02}{(AO, 571) Change \cs{balance@two}'s balancing algorithm to more successfully balance extremely short columns.}
-%    \begin{macrocode}
-\def\balance@two#1#2{%
- \ltxgrid@info@sw{\class@info{\string\balance@two\string#1\string#2}}{}%
- \outputdebug@sw{\trace@scroll{\showbox#1\showbox#2}}{}%
-%    \end{macrocode}
-% The first step is to recover the footnotes from the bottoms of the two columns (globally, into \cmd\footsofar)
-% and to combine the text into \cmd\box\cmd\@ne, but without voiding either of the argument boxes. 
-%    \begin{macrocode}
- \setbox\thr@@\copy\footsofar
- \setbox\@ne\vbox\bgroup
-  \@ifvoid{#1}{}{%
-   \recover@column#1\footsofar\column@recovered\footins@recovered
-   \@ifvoid{#2}{}{\marry@baselines}%
-  }%
-  \@ifvoid{#2}{}{%
-   \recover@column#2\footsofar\column@recovered\footins@recovered
-  }%
- \egroup
- \outputdebug@sw{\trace@scroll{\showbox\@ne}}{}%
- \ltxgrid@foot@info@sw{\trace@scroll{\showbox\footsofar}}{}%
-%    \end{macrocode}
-% Hereunder, \cmd\dimen@\ is the split value. We adjust it until the step size is small enough, while the split is acceptable. 
-% Also, \cmd\dimen@i\ is the step size. Once this value is greater than a half point, we must iterate. 
-%    \begin{macrocode}
- \dimen@\ht\@ne\divide\dimen@\tw@
- \dimen@i\dimen@
- \vbadness\@M
- \vfuzz\maxdimen
- \splittopskip\topskip
- \loopwhile{%
-  \setbox\z@\copy\@ne\setbox\tw@\vsplit\z@ to\dimen@
-  \remove@depth\z@\remove@depth\tw@
-%    \end{macrocode}
-% The following line would provide a diagnostic of the iterations of column balancing, were we to use it.
-%    \begin{verbatim}
-%  \outputdebug@sw{\trace@scroll{\showbox\tw@\showbox\z@}}{}%
-%    \end{verbatim}
-% Hereunder, \cmd\dimen@ii\ is used to reckon the difference in height between the left box and the right. 
-%    \begin{macrocode}
-  \dimen@ii\ht\tw@\advance\dimen@ii-\ht\z@
-  \dimen@i=.5\dimen@i
-  \ltxgrid@info@sw{\saythe\dimen@\saythe\dimen@i\saythe\dimen@ii}{}%
-%    \end{macrocode}
-% If the columns are within a half-point of each other, 
-%    \begin{macrocode}
-  \@ifdim{\dimen@ii<.5\p@}{%
-   \@ifdim{\dimen@ii>-.5\p@}%
-  }{%
-   \false@sw
-  }%
-%    \end{macrocode}
-% The above results in a Boolean, which now chooses between the following two brace-delimited clauses.
-% If the step size is less than a half-point, then terminate the loop. 
-%    \begin{macrocode}
-  {%
-   \true@sw
-  }{%
-   \@ifdim{\dimen@i<.5\p@}%
-  }%
-%    \end{macrocode}
-% The above results in a Boolean, which now chooses between the following two brace-delimited clauses.
-% The true-part terminates the loop, otherwise iterate. 
-%    \begin{macrocode}
-  {%
-   \false@sw
-  }%
-  {%
-%    \end{macrocode}
-% For the next iteration, the candidate split dimension \cmd\dimen@\ will be one step larger 
-% if the height of the left box is less than that of the right box. 
-% Otherwise it will be one step smaller. 
-%    \begin{macrocode}
-   \advance\dimen@\@ifdim{\dimen@ii<\z@}{}{-}\dimen@i
-   \true@sw
-  }%
- }%
-%    \end{macrocode}
-% The loop has terminated.
-%    \begin{macrocode}
- \ltxgrid@info@sw{\saythe\dimen@\saythe\dimen@i\saythe\dimen@ii}{}%
-%    \end{macrocode}
-% The algorithm has failed to find a satisfactory result if
-% the left column is of non-zero height and the right column is of zero height. 
-%    \begin{macrocode}
- \@ifdim{\ht\z@=\z@}{%
-  \@ifdim{\ht\tw@=\z@}%
- }{%
-  \true@sw
- }%
-%    \end{macrocode}
-% The \cmd\false@sw\ branch is executed if the algorithm has failed. 
-% We restore the original boxes. 
-%    \begin{macrocode}
- {%
- }{%
-  \ltxgrid@info{Unsatifactorily balanced columns: giving up}%
-  \setbox\tw@\box#1%
-  \setbox\z@ \box#2%
-  \global\setbox\footsofar\box\thr@@
- }%
- \setbox\tw@\vbox{\unvbox\tw@\vskip\z@skip}%
- \setbox\z@ \vbox{\unvbox\z@ \vskip\z@skip}%
- \set@colht
- \dimen@\ht\z@\@ifdim{\dimen@<\ht\tw@}{\dimen@\ht\tw@}{}%
- \@ifdim{\dimen@>\@colroom}{\dimen@\@colroom}{}%
- \ltxgrid@info@sw{\saythe{\ht\z@}\saythe{\ht\tw@}\saythe\@colroom\saythe\dimen@}{}%
- \setbox#1\vbox to\dimen@{\unvbox\tw@\unskip\raggedcolumn@skip}%
- \setbox#2\vbox to\dimen@{\unvbox\z@ \unskip\raggedcolumn@skip}%
- \outputdebug@sw{\trace@scroll{\showbox#1\showbox#2}}{}%
-}%
-%    \end{macrocode}
-% Procedure \cmd\remove@depth\ rearranges the given (vertical) box register so that it has zero depth. 
-%    \begin{macrocode}
-\def\remove@depth#1{%
-  \setbox#1\vbox\bgroup
-   \unvcopy#1%
-   \setbox\z@\vbox\bgroup
-    \unvbox#1%
-    \setbox\z@\lastbox
-    \aftergroup\kern\aftergroup-\expandafter
-   \egroup
-   \the\dp\z@\relax
-  \egroup
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \changes{4.1n}{2010/01/02}{(AO, 571) Abandon \cs{recover@footins} in favor of \cs{recover@column}}%
-% Procedure \cmd\recover@column\ is a utility to separate a column box into text and footnotes;
-% the former being contributed to the current (vertical) list, the latter appended to the given register, usually \cmd\footsofar. 
-% 
-% Argument \verb+#1+ is the input: it should be a \cmd\vbox, and it remains unaltered. 
-% Argument \verb+#2+ is the box into which to (globally) add the footnotes, usually \cmd\footsofar.
-% Arguments \verb+#3+ and \verb+#4+ are scratch box registers to use in this calculation.
-% As a side effect, \verb+#3+ will be unboxed into whatever vertical mode we are in at the moment (should be a \cmd\vbox). 
-%    \begin{macrocode}
-\def\recover@column#1#2#3#4{%
- \ltxgrid@info@sw{\class@info{\string\recover@column\string#1\string#2\string#3\string#4}}{}%
- \setbox#4\vbox{\unvcopy#1}%
- \ltxgrid@foot@info@sw{\trace@scroll{\showbox#4}}{}%
- \dimen@\ht#4%
- \ltxgrid@foot@info@sw{\saythe\dimen@}{}%
- \setbox#4\vbox\bgroup
-  \unvbox#4\unskip
-%    \end{macrocode}
-% We now strip the footnotes from the bottom of this box, adding them to \cmd\footsofar.
-% The method relies on a signal, consisting of a complementary pair of kerns, placed at the bottom of the box by \cmd\@combineinserts. 
-%    \begin{macrocode}
-  \dimen@i\lastkern\unkern\advance\dimen@i\lastkern
-  \@ifdim{\dimen@i=\z@}{%
-   \dimen@i\lastkern\unkern
-   \ltxgrid@foot@info@sw{\saythe\dimen@i}{}%
-   \aftergroup\dimen@i
-   \expandafter\egroup\the\dimen@i\relax
-  }{%
-   \egroup
-  }%
-%    \end{macrocode}
-% Split the column into \verb+#3+ and the footnote into \verb+#4+.
-% Append the footnote to \verb+#2+.
-%    \begin{macrocode}
- \@ifdim{\dimen@i<\z@}{%
-  \advance\dimen@\dimen@i
-  \ltxgrid@foot@info@sw{\saythe\dimen@i\saythe\dimen@}{}%
-  \splittopskip\z@skip
-  \global\setbox#3\vsplit#4 to\dimen@
-  \global\setbox#4\vbox{\unvbox#4}%
-  \ltxgrid@foot@info@sw{\trace@scroll{\showbox#1\showbox#2\showbox#3\showbox#4}}{}%
-  \global\setbox#2\vbox\bgroup\unvbox#2\vskip\z@skip\unvbox#4\egroup
- }{%
-%    \end{macrocode}
-% What if \cmd\dimen@i\ is zero? 
-% In that case, \cmd\setbox\#3\cmd\box\#4, and do not touch \cmd\box\#2.
-%    \begin{macrocode}
-  \setbox#3\box#4%
-  \ltxgrid@foot@info@sw{\trace@scroll{\showbox#1\showbox#2\showbox#3\showbox#4}}{}%
- }%
- \unvbox#3%
- \loopwhile{\dimen@\lastskip\@ifdim{\dimen@>\z@}{\unskip\true@sw}{\false@sw}}%
-}%
-\def\recover@column@null#1#2#3#4{%
- \unvcopy#1%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@begindocumenthook}
-% Initialization:
-% we initialize to the page grid named ``one''.
-% If the class decides to initially set type in a different grid, it
-% should execute these same commands, but changing the first to the appropriate procedure.
-%
-% Note that the point where this sequence is executed would be an excellent place to arrange for 
-% floats to be committed to the first page of a document. 
-% That is, we execute \cmd\do@startpage, which triggers \cmd\do@startcolumn.
-%
-% FIXME: it should be the job of the page grid to determine the procedure to execute at 
-% the start of the job. Make this a hook.
-%    \begin{macrocode}
-\rvtx@ifformat@geq{2020-10-01}%
-  {%
-    \AddToHook{begindocument}{%
-      \open@column@one\@ne
-      \set@colht
-      \@floatplacement
-      \@dblfloatplacement
-    }%
-  }{%
-    \prepdef\@begindocumenthook{%
-     \open@column@one\@ne
-     \set@colht
-     \@floatplacement
-     \@dblfloatplacement
-    }%
-  }
-%    \end{macrocode}
-% \end{macro}
-%
-% Comment: our technique of balancing columns is severely limited, because it cannot properly work
-% with \env{longtable}, which places material at the bottom and top of the column break.
-%
-% The proper way to handle a grid change in the middle of the page is to accumulate all the material for
-% an entire article (or chapter) and then assemble finished pages therefrom. This approach is fundamentally
-% superior for complex layouts: it corresponds to real-world workflows.
-% Such a scheme is an excellent subject for another \LaTeX\ package.
-%
-%
-% \subsection{Patches for the longtable package}%
-%
-% \LaTeX's ``required'' package \classname{longtable} (written by David P. Carlilsle),
-% which is part of /latex/required/tools, is incmpatible with both
-% \LaTeX's ``required'' package \classname{multicol} and with
-% \LaTeX's native \cmd\twocolumn\ capability. There is no essential reason
-% for this incompatability, aside from implementation details, and the
-% \classname{ltxgrid} package gives us the ability to lift them.
-%
-% Only four of \classname{longtable}'s procedures require rewriting:
-% \cmd\longtable,
-% \cmd\endlongtable,
-% \cmd\LT@start, and
-% \cmd\LT@end@hd@ft. 
-% The procedure \cmd\switch@longtable\ checks against their expected meanings
-% and, if all is as expected, applies the patches.
-% In the process, we simplify things considerably and also make them more
-% secure.
-%
-% Why does \classname{longtable} need to access the output routine, anyway?
-% What it comes down to, is what happens when a pagebreak falls within a
-% long table. If this happens, we would like to append a row at the bottom of
-% the broken table and add a row at the top of the next page.
-%
-% These things can be accomodated easily by the \classname{ltxgrid} output
-% routine hooks.
-%
-% \begin{macro}{\longtable}
-%    \begin{macrocode}
-\def\longtable@longtable{%
- \par
- \ifx\multicols\@undefined\else\ifnum\col@number>\@ne\@twocolumntrue\fi\fi
- \if@twocolumn\LT@err{longtable not in 1-column mode}\@ehc\fi
- \begingroup
- \@ifnextchar[\LT@array{\LT@array[x]}%
-}%
-\def\longtable@new{%
- \par
-  \@ifnextchar[\LT@array{\LT@array[x]}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\endlongtable}
-%    \begin{macrocode}
-\def\endlongtable@longtable{%
-  \crcr
-  \noalign{%
-    \let\LT@entry\LT@entry@chop
-    \xdef\LT@save@row{\LT@save@row}}%
-  \LT@echunk
-  \LT@start
-  \unvbox\z@
-  \LT@get@widths
-  \if@filesw
-    {\let\LT@entry\LT@entry@write\immediate\write\@auxout{%
-      \gdef\expandafter\noexpand
-        \csname LT@\romannumeral\c@LT@tables\endcsname
-          {\LT@save@row}}}%
-  \fi
-  \ifx\LT@save@row\LT@@save@row
-  \else
-    \LT@warn{Column \@width s have changed\MessageBreak
-             in table \thetable}%
-    \LT@final@warn
-  \fi
-  \endgraf\penalty -\LT@end@pen
-  \endgroup
-  \global\@mparbottom\z@
-  \pagegoal\vsize
-  \endgraf\penalty\z@\addvspace\LTpost
-  \ifvoid\footins\else\insert\footins{}\fi
-}%
-%    \end{macrocode}
-% \changes{4.1a}{2008/06/29}{Repair error in \cs{endlongtable@new} involving \cs{@ifx}: argument not delimited.}
-%    \begin{macrocode}
-\def\endlongtable@new{%
-  \crcr
-  \noalign{%
-   \let\LT@entry\LT@entry@chop
-   \xdef\LT@save@row{\LT@save@row}%
-  }%
-  \LT@echunk
-  \LT@start
-  \unvbox\z@
-  \LT@get@widths
-  \@if@sw\if@filesw\fi{%
-   {%
-    \let\LT@entry\LT@entry@write
-    \immediate\write\@auxout{%
-     \gdef\expandafter\noexpand\csname LT@\romannumeral\c@LT@tables\endcsname
-     {\LT@save@row}%
-    }%
-   }%
-  }{}%
-  \@ifx{\LT@save@row\LT@@save@row}{}{%
-   \LT@warn{%
-    Column \@width s have changed\MessageBreak in table \thetable
-   }\LT@final@warn
-  }%
-  \endgraf
-  \nobreak
-  \box\@ifvoid\LT@lastfoot{\LT@foot}{\LT@lastfoot}%
- \global\@mparbottom\z@
- \endgraf
- \LT@post
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\LT@start}
-%    \begin{macrocode}
-\def\LT@start@longtable{%
-  \let\LT@start\endgraf
-  \endgraf\penalty\z@\vskip\LTpre
-  \dimen@\pagetotal
-  \advance\dimen@ \ht\ifvoid\LT@firsthead\LT@head\else\LT@firsthead\fi
-  \advance\dimen@ \dp\ifvoid\LT@firsthead\LT@head\else\LT@firsthead\fi
-  \advance\dimen@ \ht\LT@foot
-  \dimen@ii\vfuzz
-  \vfuzz\maxdimen
-    \setbox\tw@\copy\z@
-    \setbox\tw@\vsplit\tw@ to \ht\@arstrutbox
-    \setbox\tw@\vbox{\unvbox\tw@}%
-  \vfuzz\dimen@ii
-  \advance\dimen@ \ht
-        \ifdim\ht\@arstrutbox>\ht\tw@\@arstrutbox\else\tw@\fi
-  \advance\dimen@\dp
-        \ifdim\dp\@arstrutbox>\dp\tw@\@arstrutbox\else\tw@\fi
-  \advance\dimen@ -\pagegoal
-  \ifdim \dimen@>\z@\vfil\break\fi
-      \global\@colroom\@colht
-  \ifvoid\LT@foot\else
-    \advance\vsize-\ht\LT@foot
-    \global\advance\@colroom-\ht\LT@foot
-    \dimen@\pagegoal\advance\dimen@-\ht\LT@foot\pagegoal\dimen@
-    \maxdepth\z@
-  \fi
-  \ifvoid\LT@firsthead\copy\LT@head\else\box\LT@firsthead\fi
-%    \end{macrocode}
-% At some point before version 4.11, the \cmd\nobreak\ was added. 
-%    \begin{macrocode}
-\nobreak
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  \output{\LT@output}%
-}%
-\def\LT@start@new{%
- \let\LT@start\endgraf
- \endgraf
- \markthr@@{}%
- \LT@pre
- \@ifvoid\LT@firsthead{\LT@top}{\box\LT@firsthead\nobreak}%
- \mark@envir{longtable}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\LT@end}
-%    \begin{macrocode}
-\def\LT@end@hd@ft@longtable#1{%
- \LT@echunk
- \ifx\LT@start\endgraf
-  \LT@err{Longtable head or foot not at start of table}{Increase LTchunksize}%
- \fi
- \setbox#1\box\z@
- \LT@get@widths\LT@bchunk
-}%
-\def\LT@end@hd@ft@new#1{%
- \LT@echunk
- \@ifx{\LT@start\endgraf}{%
-  \LT@err{Longtable head or foot not at start of table}{Increase LTchunksize}%
- }%
- \global\setbox#1\box\z@
- \LT@get@widths
- \LT@bchunk
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\LT@array}
-%
-% 
-%    \begin{macrocode}
-\def\LT@array@longtable[#1]#2{%
-  \refstepcounter{table}\stepcounter{LT@tables}%
-  \if l#1%
-    \LTleft\z@ \LTright\fill
-  \else\if r#1%
-    \LTleft\fill \LTright\z@
-  \else\if c#1%
-    \LTleft\fill \LTright\fill
-  \fi\fi\fi
-  \let\LT@mcol\multicolumn
-  \let\LT@@tabarray\@tabarray
-  \let\LT@@hl\hline
-  \def\@tabarray{%
-    \let\hline\LT@@hl
-    \LT@@tabarray}%
-  \let\\\LT@tabularcr\let\tabularnewline\\%
-  \def\newpage{\noalign{\break}}%
-  \def\pagebreak{\noalign{\ifnum`}=0\fi\@testopt{\LT@no@pgbk-}4}%
-  \def\nopagebreak{\noalign{\ifnum`}=0\fi\@testopt\LT@no@pgbk4}%
-  \let\hline\LT@hline \let\kill\LT@kill\let\caption\LT@caption
-  \@tempdima\ht\strutbox
-  \let\@endpbox\LT@endpbox
-  \ifx\extrarowheight\@undefined
-    \let\@acol\@tabacol
-    \let\@classz\@tabclassz \let\@classiv\@tabclassiv
-    \def\@startpbox{\vtop\LT@startpbox}%
-    \let\@@startpbox\@startpbox
-    \let\@@endpbox\@endpbox
-    \let\LT@LL@FM@cr\@tabularcr
-  \else
-    \advance\@tempdima\extrarowheight
-    \col@sep\tabcolsep
-    \let\@startpbox\LT@startpbox\let\LT@LL@FM@cr\@arraycr
-  \fi
-  \setbox\@arstrutbox\hbox{\vrule
-    \@height \arraystretch \@tempdima
-    \@depth \arraystretch \dp \strutbox
-    \@width \z@}%
-  \let\@sharp##\let\protect\relax
-   \begingroup
-    \@mkpream{#2}%
-    \xdef\LT@bchunk{%
-       \global\advance\c@LT@chunks\@ne
-       \global\LT@rows\z@\setbox\z@\vbox\bgroup
-       \LT@setprevdepth
-%    \end{macrocode}
-% At some point before version 4.11, the \cmd\noexpand\ was added. 
-% We need not change our own version, because we did it right, back in 1998 (using \cmd\appdef). 
-%    \begin{macrocode}
-       \tabskip\LTleft \noexpand\halign to\hsize\bgroup
-      \tabskip\z@ \@arstrut \@preamble \tabskip\LTright \cr}%
-  \endgroup
-  \expandafter\LT@nofcols\LT@bchunk&\LT@nofcols
-  \LT@make@row
-  \m@th\let\par\@empty
-  \everycr{}\lineskip\z@\baselineskip\z@
-  \LT@bchunk}%
-\def\LT@LR@l{\LTleft\z@   \LTright\fill}%
-\def\LT@LR@r{\LTleft\fill \LTright\z@  }%
-\def\LT@LR@c{\LTleft\fill \LTright\fill}%
-\def\LT@array@new[#1]#2{%
- \refstepcounter{table}\stepcounter{LT@tables}%
- \table@hook
- \LTleft\fill \LTright\fill
- \csname LT@LR@#1\endcsname
- \let\LT@mcol\multicolumn
- \let\LT@@hl\hline
- \prepdef\@tabarray{\let\hline\LT@@hl}%
- \let\\\LT@tabularcr
- \let\tabularnewline\\%
- \def\newpage{\noalign{\break}}%
- \def\pagebreak{\noalign{\ifnum`}=0\fi\@testopt{\LT@no@pgbk-}4}%
- \def\nopagebreak{\noalign{\ifnum`}=0\fi\@testopt\LT@no@pgbk4}%
- \let\hline\LT@hline
- \let\kill\LT@kill
- \let\caption\LT@caption
- \@tempdima\ht\strutbox
- \let\@endpbox\LT@endpbox
- \@ifxundefined\extrarowheight{%
-  \let\@acol\@tabacol
-  \let\@classz\@tabclassz
-  \let\@classiv\@tabclassiv
-  \def\@startpbox{\vtop\LT@startpbox}%
-  \let\@@startpbox\@startpbox
-  \let\@@endpbox\@endpbox
-%    \end{macrocode}
-% Because \classname{ltxutil} patches \LaTeX's \cmd\@tabularcr and \cmd\@xtabularcr,
-% we must restore these procedures in the scope of \env{longtable}.
-% Ironically, the patches in \classname{ltxutil} were for the purpose of extending
-% the \env{tabular} environment to prevent pagebreaks with the *-form of \cmd\\,
-% just the same as is being done here. But the two mechanisms conflict. 
-% \changes{4.1a}{2008/06/29}{Change \cs{LT@array@new}: restore \cs{@tabularcr} and \cs{@xtabularcr}}
-%    \begin{macrocode}
-  \let\LT@LL@FM@cr\@tabularcr@LaTeX
-  \let\@xtabularcr\@xtabularcr@LaTeX
- }{%
-  \advance\@tempdima\extrarowheight
-  \col@sep\tabcolsep
-  \let\@startpbox\LT@startpbox
-%    \end{macrocode}
-% \changes{4.1a}{2008/06/29}{Change \cs{LT@array@new}: set \cs{LT@LL@FM@cr} to \cs{@arraycr@array} instead of \cs{@arraycr}}
-%    \begin{macrocode}
-  \let\LT@LL@FM@cr\@arraycr@array
- }%
-%
- \let\@acoll\@tabacoll
- \let\@acolr\@tabacolr
- \let\@acol\@tabacol
-%
- \setbox\@arstrutbox\hbox{%
-  \vrule
-  \@height \arraystretch \@tempdima
-  \@depth \arraystretch \dp \strutbox
-  \@width \z@
- }%
- \let\@sharp##%
- \let\protect\relax
- \begingroup
-  \@mkpream{#2}%
-  \@mkpream@relax
-  \edef\@preamble{\@preamble}%
-  \prepdef\@preamble{%
-   \global\advance\c@LT@chunks\@ne
-   \global\LT@rows\z@
-   \setbox\z@\vbox\bgroup
-    \LT@setprevdepth
-    \tabskip\LTleft
-    \halign to\hsize\bgroup
-     \tabskip\z@
-     \@arstrut
-  }%
-  \appdef\@preamble{%
-     \tabskip\LTright
-     \cr
-  }%
-  \global\let\LT@bchunk\@preamble
- \endgroup
- \expandafter\LT@nofcols\LT@bchunk&\LT@nofcols
- \LT@make@row
- \m@th
- \let\par\@empty
- \everycr{}%
- \lineskip\z@
- \baselineskip\z@
- \LT@bchunk
-}%
-\appdef\table@hook{}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\switch@longtable}
-%
-% Here is the switch from standard \classname{longtable} to the new, \classname{ltxgrid}-compatible values.
-%
-% At this point, we extend \env{longtable} with a \env{longtable*} form, which signifies that we want to 
-% use the full page width for setting the table.
-% You can think this way: \env{longtable*} is to \env{longtable} as \env{table*} is to \env{table}.
-%
-%    \begin{macrocode}
-\def\switch@longtable{%
- \@ifpackageloaded{longtable}{%
-  \@ifx{\longtable\longtable@longtable}{%
-   \@ifx{\endlongtable\endlongtable@longtable}{%
-    \@ifx{\LT@start\LT@start@longtable}{%
-     \@ifx{\LT@end@hd@ft\LT@end@hd@ft@longtable}{%
-      \@ifx{\LT@array\LT@array@longtable}{%
-       \true@sw
-      }{\false@sw}%
-     }{\false@sw}%
-    }{\false@sw}%
-   }{\false@sw}%
-  }{\false@sw}%
-  {%
-   \class@info{Patching longtable package}%
-  }{%
-   \class@info{Patching unrecognized longtable package. (Proceeding with fingers crossed)}%
-  }%
-  \let\longtable\longtable@new
-  \let\endlongtable\endlongtable@new
-  \let\LT@start\LT@start@new
-  \let\LT@end@hd@ft\LT@end@hd@ft@new
-  \let\LT@array\LT@array@new
-  \newenvironment{longtable*}{%
-   \onecolumngrid@push
-   \longtable
-  }{%
-   \endlongtable
-   \onecolumngrid@pop
-  }%
-%    \end{macrocode}
-% Removed obsolete code.
-%    \begin{macrocode}
- }{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\LT@pre}
-% \begin{macro}{\LT@bot}
-% \begin{macro}{\LT@top}
-% \begin{macro}{\LT@post}
-% \begin{macro}{\LT@adj}
-% Note that at the end of the longtable environment, we reestablish the \cmd\mark@envir\ of the
-% containing environment. We have left \cmd\curr@envir\ alone, so this will work.
-%    \begin{macrocode}
-\def\LT@pre{\penalty\z@\vskip\LTpre}%
-\def\LT@bot{\nobreak\copy\LT@foot\vfil}%
-\def\LT@top{\copy\LT@head\nobreak}%
-\def\LT@post{\penalty\z@\addvspace\LTpost\mark@envir{\curr@envir}}%
-\def\LT@adj{%
- \setbox\z@\vbox{\null}\dimen@-\ht\z@
- \setbox\z@\vbox{\unvbox\z@\LT@bot}\advance\dimen@\ht\z@
- \global\advance\vsize-\dimen@
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{output@init}
-% \begin{macro}{output@prep}
-% \begin{macro}{output@post}
-%    \begin{macrocode}
-\def\output@init@longtable{\LT@adj}%
-\def\output@prep@longtable{\setbox\@cclv\vbox{\unvbox\@cclv\LT@bot}}%
-\def\output@post@longtable{\LT@top}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Patches for index processing}%
-%
-% Another feature that uses the output routine hooks occurs within
-% an index, where one wishes to apply a ``continue head'' when a
-% column breaks within a primary index entry. 
-% Some book designs call for the continue head to only be applied
-% at a turnpage break.
-%
-% In any case, it is easy enough for \cmd\output@post@theindex\ 
-% to do this in conjunction with component marks.
-% Only the bare outlines are shown here.
-%
-% \begin{macro}{\output@init}
-% \begin{macro}{\output@prep}
-% \begin{macro}{\output@post}
-%    \begin{macrocode}
-\let\output@init@theindex\@empty
-\let\output@prep@theindex\@empty
-\def\output@post@theindex{%
- \@ifodd\c@page{}{%
-  \@ifnum{\pagegrid@cur=\@ne}{%
-%    \end{macrocode}
-% We have the leftmost column of a verso page:
-% Insert the current top-level continued head.
-%    \begin{macrocode}
-  }%
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Checking the auxiliary file}%
-%
-% We relegate the checking of the auxiliary file to the output routine.
-% This task must wait until the last page is shipped out, because otherwise
-% the stream might get closed before the last page is shipped out.
-% Obviously, we must use \cmd\do@output@MVL\ for the job.
-%
-% \begin{macro}{\check@aux}
-%    \begin{macrocode}
-\def\check@aux{\do@output@MVL{\do@check@aux}}%
-%    \end{macrocode}
-% \end{macro}
-%
-%
-%
-% \subsection{Dealing with stuck floats and stalled float dequeueing}%
-%
-% \LaTeX's float placement mechanism is fundamentally flawed, as evidenced by 
-% its warning message ``too many unprocessed floats'', which users understandably find frustrating.
-% The \classname{ltxgrid} package provides tools for ameliorating the situation somewhat.
-%
-% Two cases require detection and rectification:
-% \begin{enumerate}
-% \item
-%  A float is ``stuck'' in the \cmd\@deferlist: for whatever reason, the float fails to be committed,
-%  even at the start of a fresh page.
-%  Once this condition prevails, following floats can never be committed, subsequently all of \LaTeX's 
-%  float registers are used up.
-%
-%  If this condition is detected, we reconsider float dequeueing under permissive (\cmd\clearpage-style) processing.
-%  
-% \item
-%  The \cmd\@freelist\ is exhausted:
-%  a large concentration of floats, say, uses up all of \LaTeX's float registers all at once.
-%  This condition commonly occurs when the user collects floats at the end of the document, for some reason.
-%
-%  When a float is encountered, \LaTeX\ uses a float register (allocated from a pool of free registers) to contain it until it can be placed.
-%  However, no further action is taken until the pagebuilder is visited, so floats can accumulate.
-%  Also, even after the pagebuilder is visited, deferred floats can accumulate, and these are not committed
-%  until a column (or page) of text is completed.
-%
-%  Once the last free float register is used, action should be taken that will commit some of the deferred floats,
-%  even if this might require ending the page right where we are (resulting in a short page).
-%
-%  Perhaps, committed floats should be stored using some mechanism other than a list, as is currently done.
-%  A feasible alternative storage method would be to use a \cmd\box\ register in place of 
-%  \cmd\@toplist,
-%  \cmd\@botlist, and
-%  \cmd\@dbltoplist.
-%  This is probably just fine, since such committed floats are not reconsidered (I think).
-%  
-% \end{enumerate}
-%
-% The  emergency processing implemented here immediately ends the current page and begins to output float pages under (\cmd\clearpage-style) rules.
-% It proceeds until all deferred floats have been flushed.
-%
-% Users should expect non-optimal page makeup under these circumstances.
-%
-% Note that there is a weakness in our approach that we have not attempted to repair: if floats are being
-% added as part of a paragraph, we will not be able to take these remedial steps until the paragraph ends.
-% This means that the approach implemented here cannot fix all \LaTeX\ documents. Users can still construct
-% documents that exhaust \LaTeX's pool of float registers!
-%
-% \begin{macro}{\check@deferlist@stuck}
-% \begin{macro}{\@outputpage@tail}
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@tail} tailpatches \cs{@outputpage}}%
-% We detect the case where, at the start of a fresh page, there are deferred floats, but none are
-% committed. We memorize the \cmd\@deferlist\ at \cmd\shipout\ time, then examine it at the point where
-% our efforts to commit floats to the new page are complete.
-% If it has not changed, the first float must be stuck, and we
-% attempt to fix things via \cmd\force@deferlist@stuck.
-%
-% This simple approach is comp[letely effective in for typical documents.
-%
-% Note that we try to avoid an infinite loop by examining the value of \cmd\clearpage@sw:
-% if we come here with that boolean true, we are in a loop.
-%    \begin{macrocode}
-\def\check@deferlist@stuck#1{%
- \@ifx{\@deferlist@postshipout\@empty}{}{%
-  \@ifx{\@deferlist@postshipout\@deferlist}{%
-   \@fltstk
-   \clearpage@sw{%
-    \ltxgrid@warn{Deferred float stuck during \string\clearpage\space processing}%
-   }{%
-    \force@deferlist@stuck#1%
-   }%
-  }{%
-%    \end{macrocode}
-% We have successfully committed float(s)
-%    \begin{macrocode}
-  }%
-  \global\let\@deferlist@postshipout\@empty
- }%
-}%
-\def\@fltstk{%
- \@latex@warning{A float is stuck (cannot be placed without \string\clearpage)}%
-}%
-\appdef\@outputpage@tail{%
- \global\let\@deferlist@postshipout\@deferlist
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@next}
-% \begin{macro}{\@xnext}
-% We rewrite the \LaTeX\ kernel macros that dequeue float registers from, e.g., \cmd\@deferlist,
-% providing a test for the condition where the pool of free registers is about to underflow.
-%
-% In this case, we attempt to fix things via \cmd\force@deferlist@empty.
-%    \begin{macrocode}
-\def\@next#1#2{%
- \@ifx{#2\@empty}{\false@sw}{%
-  \expandafter\@xnext#2\@@#1#2%
-  \true@sw
- }%
-}%
-\def\@xnext\@elt#1#2\@@#3#4{%
- \def#3{#1}%
- \gdef#4{#2}%
- \def\@tempa{#4}\def\@tempb{\@freelist}%
- \@ifx{\@tempa\@tempb}{%
-  \@ifx{#4\@empty}{%
-   \force@deferlist@empty%{Float register pool exhausted}%
-  }{}%
- }{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\force@deferlist@stuck}
-% \begin{macro}{\force@deferlist@empty}
-% \begin{macro}{\force@deferlist@sw}
-% \begin{macro}{\do@forcecolumn@pen}
-% \begin{macro}{\do@forcecolumn}
-% The procedure \cmd\force@deferlist@empty\ is an attempt to rectify a situation where \LaTeX's float placement mechanism
-% may fail (``too many unprocessed floats'').
-%
-% We put down interrupts that call for the float placement to be redone, but under permissive conditions,
-% just the same as if \cmd\clearpage\ had been invoked.
-%
-% Note that the attempt to rectify the error is contingent on the setting of \cmd\force@deferlist@sw,
-% default false. A document class using this package that wishes to enable this error recovery mechanism should
-% set this boolean to true.
-%
-% The interrupt \cmd\do@forcecolumn@pen, which invokes the procedure \cmd\do@forcecolumn,
-% does the same as \cmd\do@startcolumn, except under permissive conditions:
-% we are trying to empty out the float registers completely.
-%
-% In order to properly with the case where there is material in \cmd\box\cmd\@cclv, 
-% \cmd\@toplist, \cmd\@botlist, \cmd\@dbltoplist, etc,
-% we do what amounts to \cmd\newpage\ to get things rolling.
-%
-% In \cmd\force@deferlist@stuck, we take advantage of already being in the output routine:
-% simply reinvoke \cmd\do@startcolumn\ under permissive conditions.
-%
-%    \begin{macrocode}
-\def\force@deferlist@stuck#1{%
- \force@deferlist@sw{%
-  \@booleantrue\clearpage@sw
-  \@booleantrue\forcefloats@sw
-  #1%
- }{%
- }%
-}%
-\def\force@deferlist@empty{%
- \force@deferlist@sw{%
-  \penalty-\pagebreak@pen
-  \protect@penalty\do@forcecolumn@pen
- }{%
- }%
-}%
-\@booleanfalse\force@deferlist@sw
-\mathchardef\do@forcecolumn@pen=10009
-\@namedef{output@-\the\do@forcecolumn@pen}{\do@forcecolumn}%
-\def\do@forcecolumn{%
- \@booleantrue\clearpage@sw
- \@booleantrue\forcefloats@sw
-%    \end{macrocode}
-%    \begin{verbatim}
-%\unvbox\@cclv
-%\vfil
-%\penalty-\pagebreak@pen
-%    \end{verbatim}
-%    \begin{macrocode}
- \do@startcolumn
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% A more thorough revision of \LaTeX's float placement mechanism would involve substituting a single \cmd\box\
-% register for the \cmd\@deferlist. This way, \LaTeX's ability to have latent floats would be limited by
-% box memory alone. 
-%
-% Because only the \cmd\box\ and \cmd\count\ components of the float box register are actually used by \LaTeX,
-% our scheme can be accomplished if we can find a way to encode the information held in the \cmd\count\ component.
-%
-% A first-in, first-out mechanism exists, wherein a box-penalty pair is dequeued by \cmd\lastbox\cmd\lastpenalty\cmd\unpenalty\ and enqueued
-% by \cmd\setbox\cmd\foo=\cmd\hbox\cmd\bgroup\cmd\penalty\cmd\floatpenalty\cmd\box\cmd\floatbox\cmd\unhbox\cmd\foo\cmd\egroup.
-%
-% Note that this scheme is made possible by our change to \LaTeX's float placement mechanism,
-% wherein we consolidated the two \cmd\@deferlist s into one.
-%
-% \section{Support for legacy \LaTeX\ commands}
-%
-% We provide support for the \cmd\enlargethispage\ command.
-%
-% Note: using a command of this sort does not automatically enlarge both pages of a spread, which would be the convention in page composition.
-%
-% Timing Note: In a multicolumn page grid, the user should issue the \cmd\enlargethispage\ command 
-% while the first column of the page is being typeset. 
-% We provide a helpful message if the timing is wrong.
-%
-% This code can serve as a model for introducing commands that need to execute within the safety of the output routine.
-% We ensure that the arguments are fully expanded, then execute \cmd\do@output@MVL\ to cause an output procedure,
-% \cmd\@@enlargethispage, to execute. When it does execute, the MVL will be exposed.
-%
-% The \cmd\@@enlargethispage\ procedure simply adjusts the vertical dimensions of the page.
-% The adjustment will persist until the column is committed, at which point the page dimension
-% will revert to its standard value.
-%    \begin{macrocode}
-\def\enlargethispage{%
- \@ifstar{%
-  \@enlargethispage{}%
- }{%
-  \@enlargethispage{}%
- }%
-}%
-\def\@enlargethispage#1#2{%
- \begingroup
-  \dimen@#2\relax
-  \edef\@tempa{#1}%
-  \edef\@tempa{\noexpand\@@enlargethispage{\@tempa}{\the\dimen@}}%
-  \expandafter\do@output@MVL\expandafter{\@tempa}%
- \endgroup
-}%
-\def\@@enlargethispage#1#2{%
- \def\@tempa{one}%
- \@ifx{\thepagegrid\@tempa}{%
-  \true@sw
- }{%
-  \def\@tempa{mlt}%
-  \@ifx{\thepagegrid\@tempa}{%
-   \@ifnum{\pagegrid@cur=\@ne}{% 
-%    \end{macrocode}
-%   OK to adjust this page
-%    \begin{macrocode}
-    \gdef\enlarge@colroom{#2}%
-    \true@sw
-   }{% 
-%    \end{macrocode}
-%   Can only adjust this column; give up
-%    \begin{macrocode}
-    \ltxgrid@warn{Too late to enlarge this page; move the command to the first column.}%
-    \false@sw
-   }%
-  }{% 
-%    \end{macrocode}
-%  Unknown page grid
-%    \begin{macrocode}
-   \ltxgrid@warn{Unable to enlarge a page of this kind.}%
-   \false@sw
-  }%
- }%
- {%
-  \class@info{Enlarging page \thepage\space by #2}%
-  \global\advance\@colroom#2\relax
-  \set@vsize
- }{%
-%    \end{macrocode}
-% Could not adjust this page
-%    \begin{macrocode}
- }%
-}%
-\let\enlarge@colroom\@empty
-%    \end{macrocode}
-% The \cmd\@kludgeins\ insert register is now unneeded.
-% Ensure that packages using this mechanism break (preferrable to subtle bugs).
-%    \begin{macrocode}
-\let\@kludgeins\@undefined
-%    \end{macrocode}
-%
-% \subsubsection{Building the page for shipout}
-%
-% \begin{macro}{\@outputpage@head}
-% We set \cmd\@outputpage@head\ to make the \cmd\@outputbox\ be of fixed height.
-% \changes{4.1b}{2008/08/04}{Procedure \cs{@outputpage@head} headpatches \cs{@outputpage}}%
-%    \begin{macrocode}
-\@booleantrue\textheight@sw
-\prepdef\@outputpage@head{%
- \textheight@sw{%
-  \count@\vbadness\vbadness\@M
-  \dimen@\vfuzz\vfuzz\maxdimen
-  \setbox\@outputbox\vbox to\textheight{\unvbox\@outputbox}%
-  \vfuzz\dimen@
-  \vbadness\count@
- }{}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\@outputpage@head}
-% For compatibility with David Carlisle's \classname{lscape} package, we need to allow the 
-% \cmd\LS@rot\ procedure to mung \cmd\@outputbox. 
-%
-% Implementation note: the \classname{lscape} package effectively tailpatches two \LaTeX\ internals to accomplish its purpose,
-% an approach that is not robust. It is more robust to headpatch \cmd\@outputpage, which is what we do here. 
-% \changes{4.1o}{2010/02/02}{(AO, 576) Allow \classname{lscape} to act on \cs{@outputbox} at the right time}%
-%    \begin{macrocode}
-\appdef\@outputpage@head{%
- \@ifx{\LS@rot\@undefined}{}{\LS@rot}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \subsubsection{Warning message}
-%
-% \begin{macro}{\ltxgrid@info}
-% \begin{macro}{\ltxgrid@warn}
-% Something has happened that the user might be interested in.
-% Print a message to the log, but only if the user selected the verbose option.
-%    \begin{macrocode}
-\def\ltxgrid@info{%
- \ltxgrid@info@sw{\class@info}{\@gobble}%
-}%
-\@booleanfalse\ltxgrid@info@sw
-\def\ltxgrid@warn{%
- \ltxgrid@warn@sw{\class@warn}{\@gobble}%
-}%
-\@booleantrue\ltxgrid@warn@sw
-\@booleanfalse\ltxgrid@foot@info@sw
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \section{Line-wise processing}%
-% Sometimes we wish to process each line of type that will be placed into the galley,
-% for example, applying line numbering to a document.
-% To accomplish the task, we have to force a visit to the output routine after each such line, whereupon
-% we can process it accordingly (in the case of line numbering, we could do as \filename{lineno.sty} and
-% append an appropriately formed box to the MVL).
-%
-% In implementing such a scheme, we will have to instantiate interrupts for the following cases:
-% \begin{description}
-%
-% \item[\cmd\interlinepenalty\ and friends] These include \cmd\clubpenalty, \cmd\widowpenalty, \cmd\displaywidowpenalty, and \cmd\brokenpenalty.
-%
-%
-% \item[Display math penalties] Includes \cmd\predisplaypenalty, \cmd\postdisplaypenalty, and \cmd\interdisplaylinepenalty.
-%
-%
-% \item[\cs{par}] The penalty following the last line of the paragraph.
-%
-%
-% \item[\cmd\vadjust] A trap for any \cmd\vadjust\ command that falls in the paragraph.
-%
-% \end{description}
-%
-% \begin{macro}{\def@next@handler}
-% \begin{macro}{\def@line@handler}
-% Utility procedures \cmd\def@next@handler\ and \cmd\def@line@handler\ help in the creation of 
-% interrupt handlers. 
-%
-% \cmd\def@next@handler\ increments the scratch count register (argument 1), 
-% using this value to \cmd\mathchardef\ its second argument
-% as the negative of the flag value to be used as a penalty for exciting the interrupt (argument 3).
-% As a byproduct, it leaves the given scratch counter incremented. 
-%    \begin{macrocode}
-\def\def@next@handler#1#2#3{%
- \advance#1\@ne\mathchardef#2\the#1%
- \expandafter\def\csname output@-\the#1\endcsname{#3}%
-%    \end{macrocode}
-% The following line is for diagnostic purposes.
-%    \begin{verbatim}
-% \typeout{\string#2(\expandafter\string\csname output@\the#1\endcsname:\expandafter\meaning\csname output@\the#1\endcsname)}%
-%    \end{verbatim}
-%    \begin{macrocode}
-}%
-%    \end{macrocode}
-% \cmd\def@line@handler\ uses \cmd\int@parpenalty\ as a base.
-% The interrupt is the sum of that base with the first argument, 
-% and the handler is the second argument.
-%    \begin{macrocode}
-\def\def@line@handler#1#2{%
- \begingroup
-  \@tempcnta\int@parpenalty
-  \advance\@tempcnta-#1%
-%    \end{macrocode}
-% The following line is for diagnostic purposes.
-%    \begin{verbatim}
-%  \typeout{Defining: \expandafter\string\csname output@\the\linenopenalty\endcsname}%
-%    \end{verbatim}
-%    \begin{macrocode}
-  \aftergroup\def
-  \expandafter\aftergroup\csname output@-\the\@tempcnta\endcsname
- \endgroup{#2}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\int@parpenalty}
-% \begin{macro}{\@handle@line@ltx}
-% \begin{macro}{\@@handle@line@ltx}
-% We first set \cmd\int@parpenalty\ to our chosen base value${}\le -11012$. 
-% We then define all the handlers for lines within a paragraph, of which there are 12 different cases.
-%    \begin{macrocode}
-\mathchardef\int@parpenalty11012
-\def@line@handler\z@{\@handle@line@ltx{}{}{}}%
-\def@line@handler\@ne{\@handle@line@ltx{}{}{\brokenpenalty@ltx}}%
-\def@line@handler\tw@{\@handle@line@ltx{}{\clubpenalty@ltx}{}}%
-\def@line@handler\thr@@{\@handle@line@ltx{\clubpenalty@ltx}{}{\brokenpenalty@ltx}}%
-\def@line@handler\f@ur{\@handle@line@ltx{\widowpenalty@ltx}{}{}}%
-\def@line@handler{5}{\@handle@line@ltx{\widowpenalty@ltx}{}{\brokenpenalty@ltx}}%
-\def@line@handler{6}{\@handle@line@ltx{\widowpenalty@ltx}{\clubpenalty@ltx}{}}%
-\def@line@handler{7}{\@handle@line@ltx{\widowpenalty@ltx}{\clubpenalty@ltx}{\brokenpenalty@ltx}}%
-\def@line@handler{8}{\@handle@line@ltx{\displaywidowpenalty@ltx}{}{}}%
-\def@line@handler{9}{\@handle@line@ltx{\displaywidowpenalty@ltx}{}{\brokenpenalty@ltx}}%
-\def@line@handler{10}{\@handle@line@ltx{\displaywidowpenalty@ltx}{\clubpenalty@ltx}{}}%
-\def@line@handler{11}{\@handle@line@ltx{\displaywidowpenalty@ltx}{\clubpenalty@ltx}{\brokenpenalty@ltx}}%
-%    \end{macrocode}
-%
-% The default handler for lines within a paragraph simply 
-% restores the value of the \cmd\penalty\ to the normal value.
-% If something more useful needs to be done, we can change the definition of \cmd\@@handle@line@ltx.
-%    \begin{macrocode}
-\def\@handle@line@ltx#1#2#3{%
- \@@handle@line@ltx
- \@tempcnta\lastpenalty
- \@tempcntb\interlinepenalty@ltx\relax
- \@if@empty{#1}{}{\advance\@tempcntb#1\relax}%
- \@if@empty{#2}{}{\advance\@tempcntb#2\relax}%
- \@if@empty{#3}{}{\advance\@tempcntb#3\relax}%
- \penalty\@ifnum{\@tempcnta<\@tempcntb}{\@tempcntb}{\@tempcnta}%
-}%
-\let\@@handle@line@ltx\@empty
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\int@postparpenalty}
-% \begin{macro}{\int@vadjustpenalty}
-% \begin{macro}{\int@whatsitpenalty}
-% \begin{macro}{\int@predisplaypenalty}
-% \begin{macro}{\int@interdisplaylinepenalty}
-% \begin{macro}{\int@postdisplaypenalty}
-% \begin{macro}{\@handle@display@ltx}
-% \begin{macro}{\@@handle@display@ltx}
-% \begin{macro}{\handle@par@ltx}
-% We herewith define all the handlers for cases relating to display math:
-% last line before a display math,
-% last line of a display math, and a line within a display math.
-% We also handle the last line of a paragraph, a whatsit node, and a \cmd\vadjust.
-%    \begin{macrocode}
-\@tempcnta\int@parpenalty
-\def@next@handler\@tempcnta\int@postparpenalty{\reset@queues@ltx\handle@par@ltx}%
-\def@next@handler\@tempcnta\int@vadjustpenalty{\handle@vadjust@ltx}%
-\def@next@handler\@tempcnta\int@whatsitpenalty{\handle@whatsit@ltx}%
-\def@next@handler\@tempcnta\int@predisplaypenalty{\reset@queues@ltx\@handle@display@ltx{\predisplaypenalty@ltx}}%
-\def@next@handler\@tempcnta\int@interdisplaylinepenalty{\@handle@display@ltx{\interdisplaylinepenalty@ltx}}%
-\def@next@handler\@tempcnta\int@postdisplaypenalty{\@handle@display@ltx{\postdisplaypenalty@ltx}}%
-%    \end{macrocode}
-% The default handler for display math lines simply 
-% restores the value of the \cmd\penalty\ to the normal value.
-% If something more useful needs to be done, we can change the definition of \cmd\@@handle@display@ltx. 
-%    \begin{macrocode}
-\def\@handle@display@ltx#1{%
- \@@handle@display@ltx
- \@tempcnta\lastpenalty
- \@tempcntb#1%
- \penalty\@ifnum{\@tempcnta<\@tempcntb}{\@tempcntb}{\@tempcnta}%
-}%
-\let\@@handle@display@ltx\@empty
-%    \end{macrocode}
-%
-% We provide stub definitions for the handlers for the last line of a paragraph, a \cmd\vadjust, and a whatsit node (e.g., \cmd\write, \cmd\special). 
-% There is no canonical penalty for such cases.
-%    \begin{macrocode}
-\def\handle@par@ltx{}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% Note that a whatsit needs to be handled differently from a \cmd\vadjust:
-% a whatsit node does not affect the (crucial) depth of \cmd\box\cmd\@cclv, while the more
-% general \cmd\vadjust\ may cause any kind of vertical mode material to be interposed just below the line
-% we are trying to trap, in particular \cmd\vskip s and \cmd\penalty s.
-%
-% \begin{macro}{\set@linepenalties}
-% \begin{macro}{\restore@linepenalties}
-% \begin{macro}{\set@displaypenalties}
-% Now we define utility procedures that set up for a paragraph to be broken into lines, 
-% restoring the penalties afterwards.
-% 
-% Utility procedure \cmd\set@linepenalties\ systematically sets the penalties of paragraph breaking
-% to flag values, meanwhile storing away the normal values for access by the output routine. 
-%    \begin{macrocode}
-\def\set@linepenalties{%
- \expandafter\def\expandafter\interlinepenalty@ltx\expandafter{\the\interlinepenalty}%
- \interlinepenalty-\int@parpenalty
- \expandafter\def\expandafter\brokenpenalty@ltx\expandafter{\the\brokenpenalty}%
- \brokenpenalty\@ne
- \expandafter\def\expandafter\clubpenalty@ltx\expandafter{\the\clubpenalty}%
- \clubpenalty\tw@
- \expandafter\def\expandafter\widowpenalty@ltx\expandafter{\the\widowpenalty}%
- \widowpenalty\f@ur
- \expandafter\def\expandafter\displaywidowpenalty@ltx\expandafter{\the\displaywidowpenalty}%
- \displaywidowpenalty8\relax
-}%
-%    \end{macrocode}
-%
-% Utility procedure \cmd\restore@linepenalties\ restores the values of the penalty parameters that were
-% modified by \cmd\set@linepenalties.
-%    \begin{macrocode}
-\def\restore@linepenalties{%
- \interlinepenalty\interlinepenalty@ltx
- \brokenpenalty\brokenpenalty@ltx
- \clubpenalty\clubpenalty@ltx
- \widowpenalty\widowpenalty@ltx
- \displaywidowpenalty\displaywidowpenalty@ltx
- \relax
-}%
-%    \end{macrocode}
-%
-% In the following, the first argument should be a boolean (either \cmd\true@sw\ or \cmd\false@sw).
-%    \begin{macrocode}
-\def\set@displaypenalties#1{%
- \expandafter\def\expandafter\predisplaypenalty@ltx\expandafter{\the\predisplaypenalty}%
- \expandafter\def\expandafter\interdisplaylinepenalty@ltx\expandafter{\the\interdisplaylinepenalty}%
- \expandafter\def\expandafter\postdisplaypenalty@ltx\expandafter{\the\postdisplaypenalty}%
- \@ifhmode{\predisplaypenalty-\int@predisplaypenalty\relax}{}%
- #1{\interdisplaylinepenalty-\int@interdisplaylinepenalty\relax}{}%
- #1{\postdisplaypenalty-\int@postdisplaypenalty\relax}{}%
-}%
-%    \end{macrocode}
-% We provide no procedure to restore the respective penalties, because they are altered within a group:
-% \TeX 's context stack will automatically restore things.
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\enqueue@whatsit@ltx}%
-% \begin{macro}{\handle@whatsit@ltx}%
-% \begin{macro}{\do@whatsit}%
-% \begin{macro}{\@g@pop@ltx}%
-% Here is a facility for dealing with whatsit nodes while we are trapping paragraph lines. 
-% We simply enqueue a macro that will create the desired whatsit node, dequeueing it in the output routine.
-%    \begin{macrocode}
-\def\enqueue@whatsit@ltx#1{%
- \gappdef\g@whatsit@queue{{#1}}%
- \vadjust{\penalty-\int@whatsitpenalty}%
-}%
-\def\handle@whatsit@ltx{%
- \unvbox\@cclv
- \g@pop@ltx\g@whatsit@queue\@tempa
- \expandafter\do@whatsit\expandafter{\@tempa}%
-}%
-\def\do@whatsit#1{}%
-\def\g@pop@ltx#1#2{%
- \expandafter\@g@pop@ltx#1{}{}\@@#1#2%
-}%
-\def\@g@pop@ltx#1#2\@@#3#4{%
- \gdef#3{#2}%
- \def#4{#1}%
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vspace}%
-% \begin{macro}{\pagebreak}%
-% \begin{macro}{\nopagebreak}%
-% \begin{macro}{\\}%
-% \begin{macro}{\@arrayparboxrestore}%
-% We wish to prevent \filename{lineno.sty} from patching \cmd\vspace\ and \cmd\pagebreak, 
-% because that package does it through global assignments, which is prone to failure. 
-%
-% We also wish to prevent that package from patching \cmd\@arrayparboxrestore, because
-% it prevents us from \cmd\unvbox ing vertical mode material into the MVL and numbering those
-% lines.
-% 
-% We start by retaining the original definitions of these commands, so we can restore them
-% if \filename{lineno.sty} does get loaded. 
-%    \begin{macrocode}
-\let\vspace@ltx\vspace
-\let\pagebreak@ltx\pagebreak
-\let\nopagebreak@ltx\nopagebreak
-\let\endline@ltx\\
-\let\@arrayparboxrestore@ltx\@arrayparboxrestore
-%    \end{macrocode}
-%
-% Next, we provide for line-wise processing by patching the procedures associated with these same three commands.
-%
-% Depending on the running version of \LaTeX, these commands use \cs{vskip} (before 2020-10-01), or
-% \cs{@vspace@calcify} to add \textsf{calc}-like support in the kernel.  To avoid duplicating the tests,
-% define a macro \cs{@tempa} that takes the right form of the primitive spacing command and defines \LaTeX's
-% spacing macros accordingly.
-%    \begin{macrocode}
-\def\@tempa#1{%
-%    \end{macrocode}
-%
-% There are exactly four core \LaTeX\ procedures that use \cmd\vadjust\ to insert vertical mode material 
-% into the main vertical list: \cmd\vspace, \cmd\pagebreak, \cmd\nopagebreak, and \cmd\\. 
-% Other commands may use \cmd\vadjust, but they are inserting an interrupt (via a penalty${}<10000$), 
-% and such a thing does not mask the depth of \cmd\box\cmd\@cclv, hence is permissible.
-%
-% In each case, we replace the core \LaTeX\ procedure with one that itself replaces \cmd\vadjust\ with
-% \cmd\ex@vadjust@ltx. The meaning of this procedure can be left as \cmd\vadjust, or it can be changed to
-% one that accomplishes the equivalent without masking the depth of \cmd\box\cmd\@cclv.
-% 
-% The first procedure is \cmd\@vspace, here shown in original form and in the patched alternative form. 
-% This procedure and \cmd\@vspacer\ implement the \cmd\vspace\ command.
-%
-%    \begin{macrocode}
-\def\@vspace@org ##1{%
-  \ifvmode
-    #1% \vskip #1
-    \vskip\z@skip
-   \else
-     \@bsphack
-     \vadjust{\@restorepar
-              #1% \vskip #1
-              \vskip\z@skip
-              }%
-     \@esphack
-   \fi
-}%
-\def\@vspace@ltx##1{%
- \@ifvmode{%
-  #1% \vskip #1
-  \vskip\z@skip
- }{%
-  \@bsphack
-  \ex@vadjust@ltx{%
-   \@restorepar
-   \nobreak
-   #1% \vskip #1
-   \vskip\z@skip
-  }%
-  \@esphack
- }%
-}%
-%    \end{macrocode}
-% 
-% The second procedure is \cmd\@vspacer.
-%    \begin{macrocode}
-\def\@vspacer@org##1{%
-  \ifvmode
-    \dimen@\prevdepth
-    \hrule \@height\z@
-    \nobreak
-    #1%\vskip #1
-    \vskip\z@skip
-    \prevdepth\dimen@
-  \else
-    \@bsphack
-    \vadjust{\@restorepar
-             \hrule \@height\z@
-             \nobreak
-             #1%\vskip #1
-             \vskip\z@skip}%
-    \@esphack
-\fi
-}%
-\def\@vspacer@ltx##1{%
- \@ifvmode{%
-  \dimen@\prevdepth
-  \hrule\@height\z@
-  \nobreak
-  #1%\vskip#1
-  \vskip\z@skip
-  \prevdepth\dimen@
- }{%
-  \@bsphack
-  \ex@vadjust@ltx{%
-   \@restorepar
-   \hrule\@height\z@
-   \nobreak
-   #1%\vskip#1
-   \vskip\z@skip
-  }%
-  \@esphack
- }%
-}%
-%    \end{macrocode}
-%
-% Now define the macros above conditionally depending on the \LaTeX version.
-%    \begin{macrocode}
-}
-\rvtx@ifformat@geq{2020/10/01}%
-  {\@tempa{\@vspace@calcify{#1}}}%
-  {\@tempa{\vskip #1 }}%
-%    \end{macrocode}
-%
-% The procedure \cmd\@no@pgbk\ implements both \cmd\pagebreak\ and \cmd\nopagebreak.
-%    \begin{macrocode}
-\def\@no@pgbk@org #1[#2]{%
-  \ifvmode
-    \penalty #1\@getpen{#2}%
-  \else
-    \@bsphack
-    \vadjust{\penalty #1\@getpen{#2}}%
-    \@esphack
-  \fi
-}%
-\def\@no@pgbk@ltx#1[#2]{%
- \@ifvmode{%
-  \penalty#1\@getpen{#2}%
- }{%
-  \@bsphack
-  \ex@vadjust@ltx{%
-   \penalty#1\@getpen{#2}%
-  }%
-  \@esphack
- }%
-}%
-%    \end{macrocode}
-%
-% The command to end a line of type, \cmd\\, is defined via \cmd\DeclareRobustCommand,
-% so we must proceed carefully: 
-% A procedure is defined whose \cmd\long\cmd\csname\ is contructed via the incantation:
-% \cmd\csname\cmd\expandafter\cmd\@gobble\cmd\string\cmd\\ \cmd\endcsname.
-% Note the non-trivial space character after the \cmd\\: it is incorporated into 
-% the \cmd\csname.
-%
-% Here is the original core \LaTeX\ definition for 
-% the procedure involved, along with our revised version. 
-% \changes{2020/09/30}{4.2d}{Conditionally use \cs{protected} or \cs{long} to track \LaTeX{} changes.}
-%    \begin{macrocode}
-\rvtx@ifformat@geq{2020/02/02}%
-{\protected}{\long}\def\end@line@org{%
- \let\reserved@e\relax
- \let\reserved@f\relax
- \@ifstar{%
-  \let\reserved@e\vadjust
-  \let\reserved@f\nobreak
-  \@xnewline
- }%
- \@xnewline
-}%
-\rvtx@ifformat@geq{2020/02/02}%
-{\protected}{\long}\def\end@line@ltx{%
- \let\reserved@e\relax
- \let\reserved@f\relax
- \@ifstar{%
-  \let\reserved@e\ex@vadjust@ltx
-  \let\reserved@f\nobreak
-  \@xnewline
- }{%
-  \@xnewline
- }%
-}%
-%    \end{macrocode}
-% An additional procedure requiring patching has the following original core \LaTeX\
-% definition; we modify it correspondingly.
-%    \begin{macrocode}
-\def\@tempa#1{%
-  \def\@newline@org[##1]{%
-   \let\reserved@e\vadjust
-   \@gnewline{#1}% \vskip#1
-  }%
-  \def\@newline@ltx[##1]{%
-   \let\reserved@e\ex@vadjust@ltx
-   \@gnewline{#1}% \vskip#1
-  }%
-}
-\rvtx@ifformat@geq{2020/10/01}%
-  {\@tempa{\@vspace@calcify{#1}}}%
-  {\@tempa{\vskip #1}}%
-%    \end{macrocode}
-% We now install our patches. 
-% If some package overrides these macros, we will detect and complain.
-% 
-%    \begin{macrocode}
- \@ifx{\@vspace\@vspace@org}{%
-  \@ifx{\@vspacer\@vspacer@org}{%
-   \@ifx{\@no@pgbk\@no@pgbk@org}{%
-    \@ifx{\@newline\@newline@org}{%
-     \expandafter\@ifx\expandafter{%
-       \csname\rvtx@ifformat@geq{2020/02/02}%
-         {\expandafter\@gobble\string\\}%
-         {\expandafter\@gobble\string\\ }\endcsname
-       \end@line@org
-     }{%
-       \true@sw
-     }{\false@sw}%
-    }{\false@sw}%
-   }{\false@sw}%
-  }{\false@sw}%
- }{\false@sw}%
- {%
-  \class@info{Overriding \string\@vspace, \string\@vspacer, \string\@no@pgbk, \string\@newline, and \string\\ }%
-  \let\@normalcr\end@line@ltx
-  \expandafter\let
-    \csname\rvtx@ifformat@geq{2020/02/02}%
-      {\expandafter\@gobble\string\\}%
-      {\expandafter\@gobble\string\\ }\endcsname\@normalcr
-  \let\@newline\@newline@ltx
-  \let\@vspace\@vspace@ltx
-  \let\@vspacer\@vspacer@ltx
-  \let\@no@pgbk\@no@pgbk@ltx
- }{%
-  \class@warn{%
-   Failed to recognize \string\@vspace, \string\@vspacer, \string\@no@pgbk, \string\@newline, and \string\\; 
-   no patches applied. Please get a more up-to-date class,
-  }%
- }%
-%    \end{macrocode}
-% Note that we have assigned the same meaning to \cmd\@normalcr, which is necessary to \LaTeX.
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% 
-% \begin{macro}{\ex@vadjust@ltx}
-% \begin{macro}{\enqueue@vadjust@ltx}
-% \begin{macro}{\handle@vadjust@ltx}
-% \begin{macro}{\g@vadjust@line}
-% \begin{macro}{\reset@queues@ltx}
-% Here we give the default definition for \cmd\ex@vadjust@ltx\ along with
-% the definitions for the alternative version and its the associated handler. 
-%    \begin{macrocode}
-\let\ex@vadjust@ltx\vadjust
-\def\enqueue@vadjust@ltx#1{%
- \gappdef\g@vadjust@queue{{#1}}%
- \vadjust{\penalty-\int@vadjustpenalty}%
-}%
-\def\handle@vadjust@ltx{%
- \unvbox\@cclv
- \g@pop@ltx\g@vadjust@queue\@tempa
- \expandafter\gappdef\expandafter\g@vadjust@line\expandafter{\@tempa}%
-}%
-\let\g@vadjust@line\@empty
-%    \end{macrocode}
-% Procedure \cmd\reset@queues@ltx\ resets the whatsit queue and the \cmd\vadjust\ queues 
-% to their empty state. This should be done whenever we leave horizontal mode and
-% complete the processing of these queues: upon executing, effectively, primitive \cmd\par\
-% or interrupting a paragraph with display math. 
-%    \begin{macrocode}
-\def\reset@queues@ltx{%
- \global\let\g@whatsit@queue\@empty
- \global\let\g@vadjust@queue\@empty
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \section{Patching the lineno.sty package}
-%
-% \filename{lineno.sty} is a \LaTeX\ package that applies line numbering to a document.
-% The basic method is to give \cmd\interlinepenalty\ and like penalties such a value as 
-% to force a visit to the output routine, where the line of type is given its number. 
-% In order to properly measure the depth of \cmd\box\cmd\@cclv, it defers \cmd\vadjust\ 
-% commands that may insert \cmd\vskip\ or \cmd\penalty\ nodes.
-%
-% The implementation of that package, however, manipulates \cmd\holdinginserts\ in a dangerous
-% way: outside the safety of the output routine. It also alters the meaning of \cmd\vadjust\
-% using global assignments. We patch its code to avoid these problems. The \filename{ltxgrid}
-% package already has the needed mechanisms in place to do these jobs correctly.
-%
-% The methods we use can accomodate any values of penalties like \cmd\clubpenalty, etc:
-% we do not make assumptions about the range of values these penalty parameters could take.
-%
-%
-% \begin{macro}{\linenomathWithnumbers}
-% \begin{macro}{\linenomathNonumbers}
-% \begin{macro}{\endlinenomath}
-% \begin{macro}{\linenumberpar}
-% Here are the definitions of procedures in \filename{lineno.sty}
-% that alter \cmd\holdinginserts. They are current as of version v4.41, 2005/11/02.
-% We patch them to avoid doing this: in ltxgrid-based classes like REVTeX, the output routine properly manages \cmd\holdinginserts, so packages should not attempt to do so.
-% Also, we will want \cmd\linenumberpar\ to set \cmd\interlinepenaly\ to dispatch to \cmd\MakeLineNo. 
-%
-%    \begin{macrocode}
-\newcommand\linenomathWithnumbers@LN{%
-  \ifLineNumbers 
-    \ifnum\interlinepenalty>-\linenopenaltypar
-      \global\holdinginserts\thr@@ 
-      \advance\interlinepenalty \linenopenalty
-     \ifhmode
-      \advance\predisplaypenalty \linenopenalty
-     \fi 
-      \advance\postdisplaypenalty \linenopenalty
-      \advance\interdisplaylinepenalty \linenopenalty
-    \fi
-  \fi
-  \ignorespaces
-}%
-\newcommand\linenomathNonumbers@LN{%
-  \ifLineNumbers 
-    \ifnum\interlinepenalty>-\linenopenaltypar
-      \global\holdinginserts\thr@@ 
-      \advance\interlinepenalty \linenopenalty
-     \ifhmode
-      \advance\predisplaypenalty \linenopenalty
-     \fi 
-    \fi
-  \fi
-  \ignorespaces
-}%
-\def\endlinenomath@LN{% 
-  \ifLineNumbers
-   \global\holdinginserts\@LN@outer@holdins
-  \fi 
-  \global\@ignoretrue
-}
-\def\linenumberpar@LN{%
-  \ifvmode \@@@par \else 
-    \ifinner \@@@par \else
-      \xdef\@LN@outer@holdins{\the\holdinginserts}%
-      \advance \interlinepenalty \linenopenalty
-      \linenoprevgraf \prevgraf
-      \global \holdinginserts \thr@@ 
-      \@@@par
-      \ifnum\prevgraf>\linenoprevgraf
-        \penalty-\linenopenaltypar
-      \fi
-      \@LN@parpgbrk 
-      \global\holdinginserts\@LN@outer@holdins
-      \advance\interlinepenalty -\linenopenalty
-    \fi
-  \fi
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\class@documenthook}
-% We patch only if we recognize the definitions of all the procedures we are to patch. 
-%    \begin{macrocode}
-\appdef\class@documenthook{%
- \@ifpackageloaded{lineno}{%
-  \@ifx{\linenomathWithnumbers\linenomathWithnumbers@LN}{%
-   \@ifx{\linenomathNonumbers\linenomathNonumbers@LN}{%
-    \@ifx{\endlinenomath\endlinenomath@LN}{%
-     \@ifx{\linenumberpar\linenumberpar@LN}{%
-      \true@sw
-     }{\false@sw}%
-    }{\false@sw}%
-   }{\false@sw}%
-  }{\false@sw}%
-  {%
-   \class@info{Overriding lineo.sty, restoring output routine,}%
-%    \end{macrocode}
-% We commence overriding the procedures of \filename{lineno.sty}.
-%    \begin{macrocode}
-   \let\linenumberpar\linenumberpar@ltx
-   \let\endlinenomath\endlinenomath@ltx
-   \expandafter\let\csname endlinenomath*\endcsname\endlinenomath@ltx
-   \let\linenomathWithnumbers\linenomathWithnumbers@ltx
-   \let\linenomathNonumbers\linenomathNonumbers@ltx
-%    \end{macrocode}
-% Override \filename{lineno.sty}'s equipment for \cmd\vadjust\ and \cmd\linelabel:
-% we have existing interrupts and handlers for these purposes. 
-%    \begin{macrocode}
-   \let\ex@vadjust@ltx\ex@vadjust@line
-   \let\@LN@postlabel\enqueue@whatsit@ltx
-   \let\do@whatsit\write@linelabel
-%    \end{macrocode}
-% Redirect handlers to those provided by \filename{lineno.sty}, and
-% give an appropriate meaning to the respective headpatch within the handlers.
-%    \begin{macrocode}
-   \let\handle@par@ltx\handle@par@LN
-   \let\@@handle@line@ltx\Make@LineNo@ltx
-   \let\@@handle@display@ltx\Make@LineNo@ltx
-%    \end{macrocode}
-% Next, we undo the action taken by \filename{lineno.sty} wherein it
-% took over the output routine. Instead, we service \filename{lineno.sty}
-% existing equipment of \filename{ltxgrid}.
-% We also revert the core \LaTeX\ definitions of 
-% \cmd\vspace, \cmd\pagebreak, \cmd\nopagebreak, and \cmd\\,
-% which that package takes over (we have our own ways of doing these things). 
-%    \begin{macrocode}
-   \output@latex{\natural@output}%
-   \let\vspace\vspace@ltx
-   \let\pagebreak\pagebreak@ltx
-   \let\nopagebreak\nopagebreak@ltx
-   \let\@arrayparboxrestore\@arrayparboxrestore@ltx
-   \let\\\endline@ltx
-%    \end{macrocode}
-% \changes{4.1f}{2009/07/07}{(AO, 515) Prevent line numbering within a footnote}
-% When line numbering  is in effect, we must avoid any attempt to number the lines of a footnote.
-%    \begin{macrocode}
-   \appdef\set@footnotefont{%
-    \let\par\@@@par
-    \let\@@par\@@@par
-   }%
-%    \end{macrocode}
-% At last, we detect if the \cmd\linenumbers\ command has already been given; 
-% if so, we do its assignments again, because we have changed the meaning of \cmd\linenumberpar. 
-%    \begin{macrocode}
-   \@if@sw\ifLineNumbers\fi{%
-    \class@info{Reinvoke \string\linenumbers}%
-    \let\@@par\linenumberpar
-    \@ifx{\@par\linenumberpar@LN}{\let\@par\linenumberpar}{}%
-    \@ifx{\par\linenumberpar@LN}{\let\par\linenumberpar}{}%
-   }{%
-    \class@info{Line numbering not turned on yet}%
-   }%
-%    \end{macrocode}
-% Here ends the ``true branch'' of the patch code.
-%    \begin{macrocode}
-  }{%
-%    \end{macrocode}
-% If the \filename{lineno.sty} package is loaded, but we fail to patch it, notify the user.
-%    \begin{macrocode}
-   \class@warn{Failed to recognize lineno.sty procedures; no patches applied. Please get a more up-to-date class.}%
-  }%
- }{%
-%    \end{macrocode}
-% \filename{lineno.sty} is not loaded, so no patches are needed. 
-%    \begin{macrocode}
- }%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\linenumberpar}
-% \begin{macro}{\@linenumberpar}
-% Procedure \cmd\linenumberpar\ takes the place of \cmd\par\ when line numbering is in effect; 
-% It executes the \cmd\par\ primitive if we are in vertical mode.
-% Otherwise we are in horizontal mode in the MVL and wish to end the current paragraph,
-% or we have \cmd\unvbox ed material onto the MVL. 
-% 
-%    \begin{macrocode}
-\def\linenumberpar@ltx{\@ifvmode{\@@@par}{\@linenumberpar}}%
-%    \end{macrocode}
-%
-% Procedure \cmd\@linenumberpar
-%    \begin{macrocode}
-\def\@linenumberpar{%
-%    \end{macrocode}
-% Prepare for our trip into the output routine by 
-% saving away the current value of \cmd\prevgraf. 
-%    \begin{macrocode}
-   \linenoprevgraf\prevgraf
-%    \end{macrocode}
-% The following will be used in the output routine dispatcher
-% to sense that we came from here. 
-%    \begin{macrocode}
-   \set@linepenalties
-%    \end{macrocode}
-% Finally, call primitive \cmd\par\ with the signal value of \cmd\interlinepenalty\ and friends. 
-%    \begin{macrocode}
-   \@@@par
-%    \end{macrocode}
-% We are now in vertical mode. 
-% If lines of type were contributed to the MVL (non-trivial paragraph),
-% we must force another trip into the output routine to apply
-% line numbering to the last line of the paragraph.
-%    \begin{macrocode}
-   \@ifnum{\prevgraf>\linenoprevgraf}{
-    \penalty-\int@postparpenalty
-   }{}%
-%    \end{macrocode}
-% Execute procedure \cmd\@LN@parpgbrk, which has been set up in the 
-% output routine for us to invoke here.
-% 
-%    \begin{macrocode}
-   \@LN@parpgbrk
-%    \end{macrocode}
-% To wrap things up, we restore the original value of \cmd\interlinepenalty\ and friends.
-%
-% Query: why not employ \TeX's context stack to do the restore?
-% Would there be something wrong with executing primitive \cmd\par\ within a group?
-%    \begin{macrocode}
-   \restore@linepenalties
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\linenomathWithnumbers}
-% \begin{macro}{\linenomathNonumbers}
-% Here are the patched definitions for the commands enabling 
-% line numbering in display math. 
-%    \begin{macrocode}
-\newcommand\linenomathWithnumbers@ltx{\@linenomathnumbers@ltx\true@sw}%
-\newcommand\linenomathNonumbers@ltx{\@linenomathnumbers@ltx\false@sw}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@linenomathnumbers}
-% \begin{macro}{\endlinenomath}
-% We have just begun a display math, and any paragraph we are setting will now end.
-% We set all relevant penalties to interrupt values; in the visit to the output routine, 
-% we will replace the penalty with its normal value. 
-%    \begin{macrocode}
-\def\@linenomathnumbers@ltx#1{%
- \@if@sw\ifLineNumbers\fi{%
-   \set@linepenalties
-   \set@displaypenalties#1%
- }{}%
- \ignorespaces
-}%
-\def\endlinenomath@ltx{%
- \global\@ignoretrue
-}%
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% We provide a handler for the last line of a paragraph.
-%    \begin{macrocode}
-\def\handle@par@LN{%
- \Make@LineNo@ltx
-%    \end{macrocode}
-% After setting the line number, we arrange for an appropriate penalty to 
-% be laid down after this visit to the output routine ends.
-%
-% Query: why not contribute the penalty right here in the visit to the output routine?
-%    \begin{macrocode}
- \@tempcnta\lastpenalty 
- \@ifnum{\@tempcnta=\z@}{}{%
-  \expandafter\gdef
-  \expandafter\@LN@parpgbrk
-  \expandafter{% 
-   \expandafter\penalty
-               \the\@tempcnta
-%    \end{macrocode}
-% When \cmd\@LN@parpgbrk\ is executed, it resets itself to the default value,
-% \cmd\@LN@screenoff@pen. 
-%
-% Query: \cmd\@LN@screenoff@pen\ appears to try to restore the depth of the last box:
-% why is this being done outside the safety of the output routine?
-%    \begin{macrocode}
-   \global\let\@LN@parpgbrk\@LN@screenoff@pen
-  }%
- }%
-}%
-%    \end{macrocode}
-%
-% \begin{macro}{\Make@LineNo}
-% The procedure \cmd\Make@LineNo\ sets the box containing the line number itself.
-%    \begin{macrocode}
-\def\Make@LineNo@ltx{%
- \@LN@maybe@normalLineNumber
-%    \end{macrocode}
-% We measure the depth of \cmd\box\cmd\@cclv\ and unbox it.
-% At this point, it is crucial that that box have the same depth as that of the last 
-% box within it. 
-%
-% In the simple case, \cmd\box\cmd\@cclv\ is
-% a \cmd\vbox\ containing as its last box the \cmd\hbox\ of the paragraph we are processing.
-%
-% Query: under what circumstances will this \emph{not} be the case?
-%    \begin{macrocode}
- \boxmaxdepth\maxdimen\setbox\z@\vbox{\unvbox\@cclv}%
- \@tempdima\dp\z@
- \unvbox\z@
-%    \end{macrocode}
-% Then we create the box with the line number, setting its height to zero.
-%    \begin{macrocode}
- \sbox\@tempboxa{\hb@xt@\z@{\makeLineNumber}}%
- \ht\@tempboxa\z@
-%    \end{macrocode}
-% With these preparations, we invoke \cmd\@LN@depthbox, which
-% lays that box down (with its depth appropriately set):
-% this procedure depends on our having set \cmd\@tempdima\ and \cmd\@tempboxa
-% (kinda kludgy way of passing arguments, really).
-%    \begin{macrocode}
- \@LN@depthbox
-%    \end{macrocode}
-% Now increment the line number. I have relocated this token past \cmd\@LN@depthbox: 
-% this may induce a bug, but I am going to hereby force the issue: 
-% why split up the procedure that lays down boxes with a procedure that sets a register value?
-%    \begin{macrocode}
- \stepLineNumber
-%    \end{macrocode}
-% Finally, execute the \cmd\vadjust s that fell within the line that we just handled. 
-%
-% Note that \cmd\enqueue@vadjust@ltx\ had queued up all the \cmd\vadjust\ commands for the paragraph
-% into \cmd\g@vadjust@queue, laying down an (\cmd\int@vadjustpenalty) interrupt in each ones' place.
-% The interrupts associated with this line of the paragraph have now moved the tokens to \cmd\g@vadjust@line,
-% which we now expand and execute.
-%    \begin{macrocode}
- \g@vadjust@line
- \global\let\g@vadjust@line\@empty
-}%
-%    \end{macrocode}
-% 
-%    \begin{macrocode}
-\def\write@linelabel#1{% 
- \protected@write\@auxout{}{%
-  \string\newlabel{#1}{{\theLineNumber}{\thepage}{}{}{}}%
- }% 
-}%
-%    \end{macrocode}
-% 
-%    \begin{macrocode}
-\def\ex@vadjust@line{%
- \@if@sw\ifLineNumbers\fi{\enqueue@vadjust@ltx}{\vadjust}%
-}%
-%    \end{macrocode}
-% \end{macro}
-%
-% Note that the \cmd\linelabel\ commands use a mechanism different from \cmd\vadjust, 
-% embodied in the procedure \cmd\enqueue@vadjust@ltx, wherein the 
-% \cmd\write\ primitives are enqueued while the paragraph is being processed, each replaced with
-% an interrupt, then dequeued and executed by the interrupt handler, leaving a \cmd\write\ node
-% in place of the interrupt (just where the \cmd\vadjust 's vertical mode material would had been) 
-% just below the box containing the line of type. This \cmd\write, like all whatsits,
-% does not affect the depth of \cmd\box\cmd\@cclv, unlike the case of general vertical mode material,
-% which could have interfered.
-%
-% \section{End of the \file{ltxgrid} {\sc docstrip} module}
-% Here ends the module.
-%    \begin{macrocode}
-%</kernel>
-%    \end{macrocode}
-%
-% \Finale
-% %Here ends the programmer's documentation.
-% \endinput
-%
-\endinput
-%%EOF