syntonly.dtx
% \iffalse meta-comment
%
% Copyright (C) 1993-2024
% The LaTeX Project and any individual authors listed elsewhere
% in this file.
%
% This file is part of the LaTeX base system.
% -------------------------------------------
%
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
% https://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008 or later.
%
% This file has the LPPL maintenance status "maintained".
%
% The list of all files belonging to the LaTeX base distribution is
% given in the file `manifest.txt'. See also `legal.txt' for additional
% information.
%
% The list of derived (unpacked) files belonging to the distribution
% and covered by LPPL is defined by the unpacking scripts (with
% extension .ins) which are part of the distribution.
%
% \fi
%%
%
%
% \changes{v2.1a}{1994/03/10}{Update for \LaTeXe}
%
% \DoNotIndex{\@cclvi,\@cclv,\@gobble,\@gobbletwo,\@ifnextchar}
% \DoNotIndex{\@M,\@tempboxa,\advance,\alloc,\begingroup,\bgroup}
% \DoNotIndex{\box,\count@,\def,\do,\docdate,\egroup,\endgroup}
% \DoNotIndex{\fi,\filedate,\fileversion,\font,\fontdimen,\global}
% \DoNotIndex{\ifinner,\ifnum,\immediate,\let,\long,\loop,\m@ne}
% \DoNotIndex{\noexpand,\relax,\repeat,\scriptfont}
% \DoNotIndex{\scriptscriptfont,\setbox,\sixt@@n,\space,\textfont}
% \DoNotIndex{\toks,\toksdef,\write,\xdef,\z@}%
%
%
%\title{The file \texttt{syntonly.dtx} for use with
% \LaTeXe.\thanks{This file has version
% number \fileversion, dated \filedate.}\\[2pt]
% It contains the code for \texttt{syntonly.sty}}
% \author{Frank Mittelbach \and Rainer Sch\"opf}
%
%
% \MaintainedByLaTeXTeam{latex}
% \maketitle
%
% This package implements the |\syntaxonly| declaration for \LaTeXe.
% This command can be used in the preamble for running a document
% through \LaTeX{} without actually getting any output.
%
% \MaybeStop{}
%
%
% \section{Identification}
%
% We identify the package and its current version.
% \changes{v2.1b}{1995/04/22}{Removed surplus \cs{typeout} lines}
% \changes{v2.1c}{1996/06/14}{Rearrange \cs{GetFileInfo} usage.}
% \changes{v2.1d}{1998/08/17}{(RmS) Minor documentation fixes.}
%
% \begin{macrocode}
%<package>\ProvidesPackage{syntonly}
%<*dtx>
\ProvidesFile{syntonly.dtx}
%</dtx>
%<*package|dtx>
[2017/06/30 v2.1e Standard LaTeX2e package]
%</package|dtx>
% \end{macrocode}
%
%\iffalse
%
% \section{The documentation driver file}
%
% The next bit of code contains the documentation driver file for
% \TeX{}, i.e., the file that will produce the documentation you are
% currently reading. It will be extracted from this file by the \dst{}
% program.
% \begin{macrocode}
%<*driver>
\documentclass{ltxdoc}
\GetFileInfo{syntonly.dtx}
\providecommand\dst{\expandafter{\normalfont\scshape docstrip}}
\begin{document}
\DocInput{syntonly.dtx}
\end{document}
%</driver>
% \end{macrocode}
%\fi
%
%
% \section{Implementation}
%
% \begin{macrocode}
%<*package>
% \end{macrocode}
%
% \begin{macro}{\dummyft@}
% First of all we need to define the `dummy' font.
% \begin{macrocode}
\font\dummyft@=dummy \relax
% \end{macrocode}
% \end{macro}
% \changes{v2.1b}{1995/05/25}{Removed unneeded fontdimen settings for
% dummyft@}
%
% \begin{macro}{\ifsyntax@}
% Now we can define the `syntax only' feature. We define a switch
% |\if@syntax| so that any macro can always find out if it
% is really supposed to typeset text. Its default is to run in
% normal mode.
% \begin{macrocode}
\newif\ifsyntax@
\syntax@false
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\syntaxonly}
% The |\syntaxonly| macro sets up everything for syntax
% checking.
% \begin{macrocode}
\def\syntaxonly{%
% \end{macrocode}
% First of all it sets the |syntax@| switch to \texttt{true}.
% \begin{macrocode}
\syntax@true
% \end{macrocode}
% Then it globally sets all fonts to the dummy font. These are:
% the current font outside math mode,
% \begin{macrocode}
\global\dummyft@
% \end{macrocode}
% and the $3\times16$ math fonts for the $16$ math \emph{groups}.
% We use a loop to set these.
% \begin{macrocode}
\count@\sixt@@n
\loop
\ifnum\count@ >\z@
\advance\count@\m@ne
\global\textfont\count@\dummyft@
\global\scriptfont\count@\dummyft@
\global\scriptscriptfont\count@\dummyft@
\repeat
% \end{macrocode}
% Since all font changes occur either via |\selectfont| (in
% text or |\mathversion| (for math mode) it is sufficient
% to change these to no-ops. In addition we must prevent
% the loading of math fonts, this is done by making
% |\getanddefine@fonts| a no-op.
% \begin{macrocode}
\global\let\selectfont\relax
\global\let\mathversion\@gobble
\global\let\getanddefine@fonts\@gobbletwo
% \end{macrocode}
% We prevent \TeX{} from complaining about the dummy font
% having no characters.
% \begin{macrocode}
\tracinglostchars\z@
% \end{macrocode}
% Then we disable the output routine, and set |\frenchspacing|
% (which is slightly faster than |\nonfrenchspacing|).
% Finally we set |\hbadness| to $10000$ to avoid overfull box
% messages.
% \begin{macrocode}
\nopages@
\frenchspacing
\hbadness\@M}
% \end{macrocode}
% \end{macro}
%
% \changes{v2.1b}{1995/05/25}{Removed non-outer newtoks@: newtoks is no
% longer outer}
%
% \begin{macro}{\nopages@}
% \changes{v1.0b}{1990/01/14}{Rewrite of the \cs{nopages@} macro to
% correctly handle footnote insertions, floats and marginpars.}
% The |\nopages@| macro disables the \LaTeX{} output routine.
% To this end we define a very simple output routine that empties
% the output \emph{and} footnote boxes (remember that the latter
% are insertions.
% \begin{macrocode}
\def\nopages@{%
\output {\setbox\z@\box\@cclv
\setbox\z@\box\footins
\deadcycles\z@}%
% \end{macrocode}
% Then we protect it against definition by a style file.
% \changes{v2.1b}{1995/05/25}{newtoks is no longer outer}
% \begin{macrocode}
\newtoks\output
% \end{macrocode}
% But this is not enough: normally the \LaTeX{} output routine
% is responsible for dealing with floating objects.
% We therefore also redefine the internal macros for handling
% floats and marginpars.
% \begin{macrocode}
\def\@xfloat##1[##2]{%
% \end{macrocode}
% There are a few things that have to be retained:
% the definition of |\@captype| since it is used by the
% |\caption| command,
% \changes{v1.0c}{1990/01/16}{Definition of \cs{@captype} added.}
% \begin{macrocode}
\def\@captype{##1}%
% \end{macrocode}
% the error message issued when not in outer paragraph mode,
% \begin{macrocode}
\ifinner\@parmoderr\fi
% \end{macrocode}
% and the |\@parboxrestore| command for the body of the
% float. This is necessary since it restores the original
% definitions of important commands like |\par| or |\\|.
% \begin{macrocode}
\setbox\@tempboxa\vbox\bgroup\@parboxrestore}%
% \end{macrocode}
% |\end@float| must now only close the brace:
% \begin{macrocode}
\let\end@float\egroup
% \end{macrocode}
% The above would be enough also for two-column floats with the
% kernel algorithm. However with the refined algorithm inside
% \texttt{fixlxt2e} this doesn't any longer work, so there we also
% need to explicitly overwrite the end macro for two-column floats
% (the begin is still okay as it resolves to |\@xfloat| eventually).
% \begin{macrocode}
\let\end@dblfloat\egroup
% \end{macrocode}
% The redefinition of the |\marginpar| command is a bit more
% complicated since we have to check for the optional argument.
% First we redefine the command itself:
% \begin{macrocode}
\def\marginpar{\ifinner\@parmoderr\fi
% \end{macrocode}
% We open a group so that everything gathered in a temporary box
% can easily be thrown away by closing it again (see below).
% \begin{macrocode}
\begingroup \@ifnextchar [\@xmpar\@ympar}
% \end{macrocode}
% |\@xmpar| and |\@ympar| are now defined similar to
% |\@xfloat| above.
% If an optional argument is present |\@xmpar| typesets
% it in a temporary box that is thrown away later.
% Then it calls up |\@ympar| to process |\marginpar|'s
% argument.
% \changes{v1.0d}{1990/01/21}{Added forgotten \cs{vbox}.}
% \begin{macrocode}
\long\def\@xmpar[##1]{%
\setbox\@tempboxa\vbox{\@parboxrestore ##1}\@ympar}%
% \end{macrocode}
% |\@ympar| gathers its argument in the same temporary box
% and throws away its contents by closing the group opened up in
% |\marginpar| above.
% \changes{v1.0d}{1990/01/21}{Added forgotten \cs{vbox}.}
% \begin{macrocode}
\long\def\@ympar##1{%
\setbox\@tempboxa\vbox{\@parboxrestore ##1}\endgroup}%
% \end{macrocode}
% And that's all we had to do.
% \begin{macrocode}
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@preamblecmds}
% We disable the use of the |\syntaxonly| command after
% |\begin{document}|
% \begin{macrocode}
\@onlypreamble\syntaxonly
%</package>
% \end{macrocode}
% \end{macro}
%
% \Finale
\endinput
