% \def\filename{snapshot.dtx}
% \def\fileversion{2.14}
% \def\filedate{2020/06/17}
%
% \iffalse meta-comment
%
% American Mathematical Society
% Technical Support
% Publications Technical Group
% 201 Charles Street
% Providence, RI 02904
% USA
% tel: (401) 455-4080
% (800) 321-4267 (USA and Canada only)
% fax: (401) 331-3842
% email: tech-support@ams.org
%
% Copyright 1999-2003, 2004, 2010, 2012, 2020 American Mathematical Society.
%
% This work 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
% http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
%
% The Current Maintainer of this work is the American Mathematical
% Society.
%
% \fi
%
% \iffalse
%<*driver>
\NeedsTeXFormat{LaTeX2e}
\documentclass{amsdtx}
\usepackage{hyperref}
\providecommand{\qq}[1]{\textquotedblleft#1\textquotedblright}
\providecommand{\mdash}{\textemdash\penalty\exhyphenpenalty}
\providecommand{\lat}[1]{\protect\LaTeX{}}
\providecommand{\strong}[1]{\textbf{#1}}
\providecommand{\secref}[1]{Section~\ref{#1}}
\CodelineIndex
\title{The \pkg{snapshot} package}
\author{American Mathematical Society}
\date{Version \fileversion, \filedate}
\begin{document}
\DocInput{snapshot.dtx}
\PrintIndex
\end{document}
%</driver>
% \fi
%
% \MakeShortVerb{\|}
%
% \maketitle
%
% \tableofcontents
%
% \section{Introduction}
%
% The \pkg{snapshot} package helps the owner of a \LaTeX{} document
% obtain a list of the external dependencies of the document, in a
% form that can be embedded at the top of the document. To put it
% another way, it provides a snapshot of the current processing
% context of the document, insofar as it can be determined from
% inside \LaTeX{}.
%
% If a document contains such a dependency list, then it becomes
% possible to arrange that the document be processed always with the
% same versions of everything, in order to ensure the same output.
% This could be useful for someone wanting to keep a \LaTeX{}
% document on hand and consistently reproduce an identical DVI file
% from it, on the fly; or for someone wanting to shield a document
% during the final stages of its production cycle from unexpected
% side effects of routine upgrades to the \TeX{} system.
%
% Normal usage of the \pkg{snapshot} package involves the following
% steps:
% \begin{enumerate}
% \item Add a \cn{RequirePackage} statement at the top of the
% document:
% \begin{verbatim}
% \RequirePackage{snapshot}
% \documentclass{article}
% ...
% \end{verbatim}
%
% \item Run \latex/ on the document. This will produce a dependency
% list in a file \verb'\jobname.dep'. (I.e., if the document name is
% \fn{vermont.ltx}, the dependency list will be named
% \fn{vermont.dep}.)
%
% \item Insert the \fn{.dep} file at the top of the document, before
% \cn{documentclass}. The following example shows what you would end
% up with for a document that used the article documentclass and the
% graphicx package:
% \begin{verbatim}
% \RequirePackage{snapshot}[1999/11/03]
% \RequireVersions{
% *{application}{TeX} {1990/03/25 v3.x}
% *{format} {LaTeX2e} {1999/06/01 v2.e}
% *{package}{snapshot} {1999/11/03 v1.03}
% *{class} {article} {1999/01/07 v1.4a}
% *{file} {size10.clo} {1999/01/07 v1.4a}
% *{package}{graphicx} {1999/02/16 v1.0f}
% *{package}{keyval} {1999/03/16 v1.13}
% *{package}{graphics} {1999/02/16 v1.0l}
% *{package}{trig} {1999/03/16 v1.09}
% *{file} {graphics.cfg}{0000/00/00 v0.0}
% *{file} {dvips.def} {1999/02/16 v3.0i}
% }
% \documentclass{article}
% \usepackage{graphicx}
% ...
% \end{verbatim}
% \end{enumerate}
%
% The package option \opt{log} will cause the dependency list to
% appear in the \latex/ log file instead of in a separate \fn{.dep}
% file:
% \begin{verbatim}
% \RequirePackage[log]{snapshot}
% \end{verbatim}
% Making the necessary arrangements to ensure that future \latex/
% runs of the document actually call in the specified versions is a
% separate problem. The \pkg{snapshot} package only provides a way to
% generate the dependency list. However, the \cn{RequireVersions}
% statement does record the given information in a form that can be
% accessed from within \latex/. (It is for this purpose that it is not
% simply a comment.) In principle a package could be set up so that a
% later version would automatically attempt to emulate an earlier
% version if an earlier version was specified\mdash much as \latex/
% currently switches to 2.09 compatibility mode if it sees
% \cn{documentstyle} instead of \cn{documentclass}.
%
% For maximum reliability font checksums should also be reported in
% the dependency list, but standard \tex/ 3.x does not provide direct
% access to font checksums for macro programmers. This information
% could be added by a separate script that scans the DVI file.
% (Certain nontrivial complications are possible, however.)
%
% \section{Graphics files}
% When a graphics file is read in by a \latex/ document using the
% standard \cn{includegraphics} command, it gets a dummy version
% number string of
%\begin{verbatim}
%Graphics file (type foo)
%\end{verbatim}
% where foo is typically \texttt{eps}. This is with the current
% version of the \pkg{graphics} package (at the time of this writing:
% 1999/02/16 v1.0l). What this means in practice is that all graphics
% files will have their snapshot date and version number recorded as
%\begin{verbatim}
%Graphics v0.0
%\end{verbatim}
% and will always compare equal (the string ``Graphics'' will be used
% in place of a date, but since comparison is done with \cs{ifx} it
% doesn't make any real difference).
%
% It would be possible, for \fn{.eps} files at least, to read the
% CreationDate comment that is normally included in the file header
% and use that as the basis of comparison. Recording the bounding box
% numbers instead of a dummy version number is another possibility,
% which you can get with the
% \opt{bbinfo} option (as of \pkg{snapshot} version 2.05).
%
% \section{Formalities}
%
% \DescribeMacro{\RequireVersions} The \cn{RequireVersions} command
% scans its argument for file names and associated version number
% information. The syntax of a version line for a particular file is
% \begin{quote}
% \verb'*{' \emph{file type} \verb'}{' \emph{file name} \verb'}{'
% \emph{version info} \verb'}'
% \end{quote}
% In other words, the \verb'*' character in this context is like a
% command that takes three arguments. The extension part of the
% file name should be omitted in the second argument, except when the
% file type is \fn{file} (following the conventions of \latex/'s
% \cn{ProvidesPackage} and \cn{ProvidesFile} commands). The most
% commonly used file types are as follows.
% \begin{description}
% \item[class] A \latex/ documentclass file.
% \item[package] A \latex/ package file.
% \item[tfm] A \tex/ font metric file. In this case the \qq{version
% number} is the checksum, and unless you are using an extended
% version of \tex/ this information is not accessible from inside
% \latex/, so it must be filled in by an outside process.
% By default, font metric files are not listed in the dependency list
% since the checksum info is not available. There is a package option
% \opt{tfm} to turn on the logging of metric files. (Not yet
% implemented [mjd,1999/09/23])
%
% \item[format] This is almost always \fn{LaTeX2e}. The information
% comes from \cs{fmtname}. Lambda, e\LaTeX{}, and pdf\LaTeX{} leave
% \cs{fmtname} unchanged, and although this may seem dubious at first
% sight, I guess they have little choice: the widespread use of
% \cs{NeedsTeXFormat} in existing package files makes them produce an
% error message if \cs{fmtname} is changed. (Maybe the thing to do
% would be to modify the definition of \cs{NeedsTeXFormat} as well.)
%
% For a \LaTeX{} format that uses the Babel mechanism for preloading
% hyphenation patterns, the version number of \fn{babel.def} that was
% used in building the format might be of interest. But at first
% glance there does not seem to be any easy way of dealing with that,
% and in the normal course of things, a document that relies on Babel
% features will also have a \verb'\usepackage{babel}' statement at
% the top, and that will yield adequate (I think) information for the
% snapshot dependency list.
%
% \item[application] With standard \fn{TeX} there is no reliable way to
% get the exact version number from inside \LaTeX{}. If a document is
% processed with one of the recent variants that address this
% deficiency (such as e-\TeX{}, pdf\TeX{} and Omega) the available
% version info is used, but otherwise a presumptive value of
% \verb'1990/03/25 v3.x' is used (the official release date of \TeX{}
% 3.0).
%
% \item[file] None of the above: some other file of miscellaneous type,
% e.g., \fn{.clo}, \fn{.cfg}, \fn{.tex}, or \fn{.def}.
% \end{description}
%
% The \cn{RequireVersions} command can be given an optional
% \qq{ident} argument, similar to the argument of a \cn{label}
% command. This is not used internally but it could be used to
% assign a label to particular groups of files in case that helps
% with external processing.
%
% \section{Package options}
%
% The list of options supported by the \pkg{snapshot} package is as
% follows:
% \begin{center}\begin{tabular}{lll}
% dep & date\\
% log & version\\
% tfm & major-version\\
% warning & bbinfo \\
% error & test \\
% self-warning
% \end{tabular}
% \end{center}
%
% \begin{description}
% \item[dep, log] Write file date and version information to
% \textit{jobname}\fn{.dep} or to the \LaTeX{} log file, respectively.
%
% \item[error, warning, self-warning]
% If the \pkg{snapshot} package is invoked with the \opt{error}
% option \emph{and also} the document contains a \cn{RequireVersions}
% statement, then each subsequent \cn{ProvidesFile},
% \cn{ProvidesPackage}, and \cn{ProvidesClass} statement will compare
% date and version number information with the corresponding
% information from the \cn{RequireVersions} statement and give an
% error message if a mismatch is detected. With the \opt{warning}
% option you get warnings instead of errors. By default both the date
% and the version number are compared; this behavior can be modified,
% however, by giving additional options:
% \begin{description}
% \item[date] compare only dates,
% \item[version] compare only version numbers,
% \item[major-version] use only the major version number when
% comparing.
% \end{description}
%
% The \opt{self-warning} causes a warning to be given, instead of an
% error, if the \pkg{snapshot} package itself has a date or
% version mismatch.
%
% \textbf{Note:} A file that doesn't have any sort of
% \cn{ProvidesFile} or \cn{ProvidesPackage} statement in it will show
% up in the dependency list, with a dummy date and version number of
% 0000/00/00 v0.0, but testing for a version mismatch with such a
% file is then infeasible.
%
% \item[bbinfo] For files of type ``graphic'', include bounding-box info
% as the ``version number''. A normal date and version number are
% seldom available for such files, and \LaTeX{} does not attempt
% to read them, which means that the \pkg{snapshot} package could not
% obtain the information except by drastically modifying the
% low-level \LaTeX{} operations that read graphics file
% information\mdash which seems overly risky.
%
% \item[tfm] \emph{Not implemented yet!} Include information about which
% \TeX{} font metric files are called by \LaTeX{}. This list is
% usually somewhat different from the list of fonts that are actually
% used in the output file (\fn{.dvi} or \fn{.pdf}), primarily because
% the setup for math formulas will normally preload font metric
% information for all the fonts from which \LaTeX{}'s basic math
% symbols are drawn (the symbols documented in the \LaTeX{} book),
% even if the document does not use symbols from all of those fonts.
%
% \item[test] This option is for a special purpose. It drastically
% changes the action of the \cs{RequireVersions} command so that it
% does not merely record the information for later reference, but
% does a \qq{trial load attempt} for each file in the list, and then
% stops the \LaTeX{} job as soon as the list is finished, without
% continuing any further.
%
% By \qq{trial load attempt} I mean that the \cs{RequireVersions}
% command will actually input each file, but with various bits
% redefined so that \cs{ProvidesPackage} and variants will execute
% \cs{endinput}\mdash in other words, only the first few lines of
% each file will be read.
%
% What this means, practically speaking, is that if you run such a
% test on a document, it gives a relatively quick check on two useful
% pieces of information without having to retypeset the entire
% document (which for some documents might be very tedious)
% \begin{enumerate}
% \item The actual location on your system from which the file will be
% loaded.
%
% \item The date and version info from \cs{Provides...} line, if present.
% \end{enumerate}
%
% Similar results could be obtained by a combination of
% \fn{kpsewhich} and \fn{grep}, but because the \pkg{snapshot} \opt{test}
% option works through \LaTeX{}, it is a system-independent method.
%
% Caveat: If a file does not contain any \cs{ProvidesSomething} line,
% it will be read in its entirety, which might lead to errors. Or if
% there is any weird stuff preceding the \cs{ProvidesWhatever} line.
% But for well-behaved files the option seemed useful enough to be
% worth implementing.
%
% \end{description}
%
% \StopEventually{}
%
% \section{Implementation}
% Standard declaration of package name and date.
% \begin{macrocode}
\NeedsTeXFormat{LaTeX2e}[1994/12/01]
\ProvidesPackage{snapshot}[2020/06/17 v2.14]
% \end{macrocode}
%
% Calling the \pkg{snapshot} package in a document causes \latex/ to
% list the file names and versions in the \tex/ log or in a \fn{.dep}
% file, so that the information may be easily copied into the
% document file. The list so generated is nothing more than a slight
% adaptation of the output from \latex/'s \cn{listfiles} command; it
% puts essentially the same information into a slightly more
% structured form so that it will be easier to use.
%
% For the standard mechanisms that are already built into \latex/
% (e.g., the handling of the second optional argument of
% \cs{LoadClass}), the de facto \qq{version number} is the
% \emph{date} given in the optional argument of a \cn{ProvidesClass}
% or similar command. Even though most \cn{ProvidesWhatever} commands
% also give something that follows the usual form of version
% numbers\mdash a string of the form \verb'v2.3'\mdash this is only a
% convention, not used internally by \latex/, and the identification
% string of a random loaded file is not guaranteed to include it. The
% \pkg{snapshot} package copies both pieces of information if
% available; if the second piece is not present, a dummy number
% \verb'0.0' is supplied. Similarly, files that don't include any
% \cn{ProvidesWhatever} statement will get a dummy date of
% \verb'0000/00/00';
% \begin{center}\begin{minipage}{.9\columnwidth}\bfseries
% \medskip
% \tex/ system administrators who want to ensure
% maximal accuracy of the snapshot information should therefore make
% it a practice to use \cn{ProvidesFile} in \fn{.cfg} files and other
% local files that might have an impact on the output fidelity of
% their documents.
% \end{minipage}\end{center}
%
% \begin{macro}{\@xp}
% \begin{macro}{\@nx}
% A couple of shorthand forms.
% \begin{macrocode}
\let\@xp=\expandafter \let\@nx=\noexpand
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\str@cmp}
% \begin{macro}{\str@equal}
% A function to compare two strings and return FT or TT (for use with
% \cs{if}).
% \begin{macrocode}
\def\str@cmp#1#2\str@cmp#3{%
\if #1#3\else F\@car\fi \str@cmp#2\str@cmp
}
\def\string@equal#1#2{%
\str@cmp#1\relax\str@cmp#2{\relax\@gobbletwo}\@nil TT%
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\RequireVersions}
%
% Optional argument of \cn{RequireVersions} allows assigning a name to a
% particular collection of files. This might be useful for setting a
% \tex/ inputs path.
% \begin{macrocode}
\newcommand{\RequireVersions}[2][]{}%
\renewcommand{\RequireVersions}[1][]{%
\def\snap@check{\snap@compare@versions}%
\toks@{#1}%
\afterassignment\snap@storem
\let\@let@token=
}
\@onlypreamble\RequireVersions
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@storem}
% \begin{macrocode}
\def\snap@storem{%
\ifx\@let@token\bgroup \else
\PackageError{snapshot}{Expected a `\@charlb' character here}\@ehc
\@xp\@gobblefour
\fi
\futurelet\@let@token\snap@branch
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@check}
% \begin{macrocode}
\let\snap@check\@gobble
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@finish}
% \begin{macrocode}
\def\snap@finish{\toks@\bgroup}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@branch}
% \begin{macrocode}
\def\snap@branch{%
\ifx\@let@token\egroup
\@xp\snap@finish
\else\ifx\@let@token *%
\let\reserved@c\snap@store@version
\else\ifx\@let@token\@sptoken
\lowercase{\def\reserved@c} {\futurelet\@let@token\snap@branch}%
\else
\let\reserved@c\snap@store@error
\fi\fi\fi
\reserved@c
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@store@error}
% \begin{macrocode}
\def\snap@store@error#1{%
\PackageError{snapshot}{Expected '*' here, not '#1'}\@ehc
}
\@onlypreamble\snap@store@error
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@store@version}
% \begin{macrocode}
\def\snap@store@version #1#2#3#4{%
\@xp\snap@store@b\csname snapx@#2\endcsname{#2}{#3}{#4}%
}
\@onlypreamble\snap@store@version
% \end{macrocode}
% \end{macro}
%
% \subsection{Determining the engine}
%
% \begin{macro}{\snapshotApplication}
% Check for the engines that are active in \TeX Live 2020. Note
% that in in modern versions of \TeX Live, there is no distinction
% between \fn{etex}, \fn{pdfetex}, and \fn{pdftex}. I believe this
% code will distinguish between distinct legacy binaries, but I
% have not tested this thoroughly. Similar remarks apply to the
% p\TeX\ family.
%
% \begin{macrocode}
\let\snapshotApplication\@empty
\ifx\OmegaVersion\@@undefined \else
\edef\snapshotApplication{%
\ifx\AlephVersion\@@undefined
{Omega}\space\space\space
{0000/00/00 v\OmegaVersion}%
\else
{Aleph}\space\space\space
% \end{macrocode}
% \cs{AlephVersion} appears to be incorrectly set to 0.0, so
% include the Omega version as well.
% \begin{macrocode}
{0000/00/00 v\OmegaVersion-\AlephVersion}%
\fi
}%
\fi
\ifx\ptexversion\@@undefined\else
\edef\snapshotApplication{%
{pTeX}\space\space\space\space
{0000/00/00 v\number\ptexversion
\ifx\ptexminorversion\undefined \u \else.\number\ptexminorversion\fi
\ifx\ptexrevision\undefined \u \else\ptexrevision\fi}%
}%
\ifx\uptexversion\@@undefined
\ifx\epTeXversion\@@undefined\else
\edef\snapshotApplication{%
{epTeX}\space\space\space
{0000/00/00 v\number\epTeXversion}%
}%
\fi
\else
\ifx\epTeXversion\@@undefined
\edef\snapshotApplication{%
{upTeX}\space\space\space
{0000/00/00 v\number\uptexversion
\ifx\uptexrevision\undefined \u \else\uptexrevision\fi}%
}%
\else
% \end{macrocode}
% There is no separate \cs{euptexversion}, so use a combination of
% the underlying up\TeX\ and ep\TeX\ versions.
% \begin{macrocode}
\edef\snapshotApplication{%
{eupTeX}\space\space
{0000/00/00 v\number\uptexversion
\ifx\uptexrevision\undefined \u \else\uptexrevision\fi
--\number\epTeXversion}%
}%
\fi
\fi
\fi
\ifx\snapshotApplication\@empty
\ifx\XeTeXversion\@@undefined\else
\edef\snapshotApplication{%
{XeTeX}\space\space\space
{0000/00/00 v\number\XeTeXversion
\ifx\XeTeXrevision\undefined\else\XeTeXrevision\fi}%
}%
\fi
\fi
\ifx\snapshotApplication\@empty
\ifx\luatexversion\@@undefined\else
\begingroup
\@tempcnta\luatexversion
\divide\@tempcnta by 100
\edef\@tempa{\the\@tempcnta}%
\multiply\@tempcnta by 100
\@tempcntb\luatexversion
\advance\@tempcntb by -\@tempcnta
\edef\@tempa{\@tempa.\the\@tempcntb.\luatexrevision}%
\xdef\snapshotApplication{%
{luaTeX}\space\space
{0000/00/00 v\@tempa}%
}%
\endgroup
\fi
\fi
\ifx\snapshotApplication\@empty
\ifx\pdftexversion\@@undefined \else
\begingroup
\ifx\eTeXversion\@@undefined
\@tempswafalse
\else
\@tempswatrue
\fi
\@tempcnta\pdftexversion
\divide\@tempcnta by 100
\edef\@tempa{\the\@tempcnta}%
\multiply\@tempcnta by 100
\@tempcntb\pdftexversion
\advance\@tempcntb by -\@tempcnta
% \end{macrocode}
% e\TeX\ was folded into pdf\TeX\ as of version 1.40.
% \begin{macrocode}
\ifnum\@tempcntb > 39
\@tempswafalse
\fi
\edef\@tempa{\@tempa.\the\@tempcntb.\pdftexrevision}%
\xdef\snapshotApplication{%
\if@tempswa
{pdfeTeX}\space
\else
{pdfTeX}\space\space
\fi
{0000/00/00 v\@tempa}%
}%
\endgroup
\fi
\fi
\ifx\snapshotApplication\@empty
\ifx\eTeXversion\@@undefined \else
\edef\snapshotApplication{%
{eTeX}\space\space\space\space
{0000/00/00 v\number\eTeXversion
\ifx\eTeXrevision\undefined
\ifx\eTeXminorversion\undefined\else.\number\eTeXminorversion\fi
\else
\eTeXrevision
\fi
}%
}%
\fi
\fi
% \end{macrocode}
% If none of the above information is available, the exact version
% number of \TeX{} is not accessible from inside \latex/. We then
% fall back to using a nominal date of 1990/03/25, which is when
% version 3.0 of \fn{tex.web} was released by Knuth.
% \begin{macrocode}
\ifx\snapshotApplication\@empty
\edef\snapshotApplication{%
{TeX}\space\space\space\space\space
{1990/03/25 v3.x}%
}%
\fi
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
\def\@fmtextension{fmt}
\def\@tfmextension{tfm}
\edef\snapx@package{.\@pkgextension}
\edef\snapx@class{.\@clsextension}
\edef\snapx@format{.\@fmtextension}
\edef\snapx@tfm{.\@tfmextension}
\long\def\snapx@ignore{}
\let\snapx@application=\snapx@ignore
\let\snapx@file=\@empty
\let\snapx@end\@@end
\expandafter\let\csname snapx@-------\endcsname\snapx@end
% \end{macrocode}
%
% \begin{macro}{\snap@store@b}
% For a package named \fn{foo.sty}, this function defines
% \cs{rqv@foo.sty} to hold the date and version information.
% \begin{macrocode}
\def\snap@store@b#1#2#3#4{%
\ifx#1\snapx@end
\@xp\snap@finish
\else
\ifx#1\relax \let#1\@empty\fi
\def\@tempa##1 ##2 ##3\@nil{##1 ##2}%
% \end{macrocode}
%
% \begin{macrocode}
\ifx#1\snapx@application
\@xp\xdef\csname rqv@#3#1\endcsname{\@tempa#4 v?.? ? \relax\@nil}%
\else
\xdef\rqv@list{\rqv@list{#3#1}}%
\@xp\xdef\csname rqv@#3#1\endcsname{\@tempa#4 v?.? ? \relax\@nil}%
\snap@intest{#3}{#1}%
\ifx#1\snapx@format \snap@check{#3.fmt}\else
% \end{macrocode}
% Test if current file is \fn{snapshot.sty}. Need to pre-expand the
% extension part to ensure the test is correct.
% \begin{macrocode}
\edef\@tempa{\@nx\string@equal{snapshot.sty}{#3#1}}%
\if\@tempa \snap@selfcheck \fi
\fi
\fi
\fi
\futurelet\@let@token\snap@branch
}
\@onlypreamble\snap@store@b
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@write}
% Default setup is geared to write the dependency list to a \fn{.dep}
% file. The option \opt{log} means write it to the \tex/ log instead.
% \begin{macrocode}
\def\snap@write{\immediate\write\snap@out}
\let\snap@out\sixt@@n % fallback, probably never used
% \end{macrocode}
% \end{macro}
%
% \subsection{Package options}
%
% \begin{macrocode}
\DeclareOption{dep}{%
\def\snap@write{\immediate\write\snap@out}%
}
% \end{macrocode}
%
% \begin{macrocode}
\DeclareOption{log}{%
\let\snap@write\typeout
}
% \end{macrocode}
%
% The purpose of the `test' option is to support a separate testing
% procedure for resolving file names and pre-checking version
% numbers. See \secref{test} for more information.
% \begin{macrocode}
\let\snap@intest=\@gobbletwo
\DeclareOption{test}{\def\snap@intest{True}}
% \end{macrocode}
%
% For each font used by a document, we would like to list the
% \fn{.tfm} file name and checksum. If \tex/ provided a
% \cn{fontchecksum} primitive similar to \cn{fontname} that could be
% used to get the checksum of any font, it would just about be
% feasible to do this entirely from within \latex/. As a partial
% solution we could at least generate the list of font file names, to
% make it easier for an external utility to add the checksums.
%
% In practice, extracting font names and checksums from the \fn{.dvi}
% file will probably work well enough, leaving no work to be done by
% the \pkg{snapshot} package in this area. But theoretically speaking
% the output of a document could be affected by font metric files
% that are loaded during \latex/ processing but that do not show up
% in the \fn{.dvi} file.
% \begin{macrocode}
\DeclareOption{tfm}{%
\typeout{Option 'tfm' not implemented yet [1999/09/23]}%
}
% \end{macrocode}
%
% \subsubsection{Warnings and errors}
% \begin{macro}{\snap@mismatch@warning}
% \begin{macro}{\snap@mismatch}
% \begin{macrocode}
\def\snap@mismatch@warning#1#2#3{\PackageWarningNoLine{#1}{#2}}
\def\snap@mismatch{\snap@mismatch@warning}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macrocode}
\DeclareOption{error}{%
\def\snap@mismatch{\PackageError}%
\def\snap@selfcheck{\snap@selfcheck@a}%
\ifx\snap@select\@empty \let\snap@select\snap@select@all \fi
}
% \end{macrocode}
%
% \begin{macrocode}
\DeclareOption{warning}{%
\def\snap@mismatch{\snap@mismatch@warning}%
\def\snap@selfcheck{\snap@selfcheck@a}%
\ifx\snap@select\@empty \let\snap@select\snap@select@all \fi
}
% \end{macrocode}
%
%
% \begin{macro}{\snap@select@all}
% \begin{macro}{\snap@select}
% Because the exact form of the version number is not mandated by
% \LaTeX{}, just take the first two ``words'' delimited by spaces.
% And take a little extra care to properly handle multiple spaces
% between the words.
% \begin{macrocode}
\def\snap@select@all#1#2 #3#4 #5\@nil{#1#2 #3#4}
\let\snap@select\@empty
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\snap@seldate}
% \begin{macro}{\snap@selversion}
% \begin{macro}{\snap@selmajor}
% If the naming conventions seem a little peculiar here, it's because
% I had to add some pieces later that I didn't think of initially,
% and I wanted to minimize the chances of compatibility problems for
% client packages [mjd,2002-11-04].
% \begin{macrocode}
\def\snap@seldate#1#2 #3\@nil{#1#2}%
\def\snap@selversion#1#2 #3{\snap@select@version #3}%
\def\snap@selmajor#1#2 #3{\snap@select@major #3}%
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macrocode}
\DeclareOption{date}{\let\snap@select=\snap@seldate}
% \end{macrocode}
%
% \begin{macro}{\snap@select@version}
% \begin{macrocode}
\def\snap@select@version#1{%
\ifodd 0#11 \@xp\snap@sva\@xp#1\else\@xp\snap@select@version\fi
}
\def\snap@sva#1.#2 #3\@nil{#1.#2}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@select@major}
% \begin{macrocode}
\def\snap@select@major#1{%
\ifodd 0#11 \@xp\snap@svm\@xp#1\else\@xp\snap@select@major\fi
}
\def\snap@svm#1.#2\@nil{#1}
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
\DeclareOption{version}{\let\snap@select\snap@selversion}
\DeclareOption{major-version}{\let\snap@select\snap@selmajor}
% \end{macrocode}
%
% \begin{macrocode}
\def\snap@bbinfo{01}
\DeclareOption{bbinfo}{\def\snap@bbinfo{00}}
% \end{macrocode}
%
% \begin{macro}{\snap@splitter}
% Give this an inert definition, for the time being, until we are
% ready to do the split.
% \begin{macrocode}
\let\snap@splitter=?
\AtBeginDocument{%
\xdef\@filelist{\@filelist\snap@splitter}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@selfcheck}
% \begin{macrocode}
\let\snap@selfcheck\@empty
\let\snap@selfcheck@a\@empty
% \end{macrocode}
% \end{macro}
%
% The \opt{self-warning} option would normally be used in conjunction
% with the \opt{error} option.
% \begin{macrocode}
\DeclareOption{self-warning}{%
\def\snap@selfcheck{%
\begingroup
\def\snap@mismatch{\snap@mismatch@warning}%
\snap@selfcheck@a
\endgroup
}
}
% \end{macrocode}
%
% \begin{macrocode}
\ExecuteOptions{warning}
\ProcessOptions\relax
% \end{macrocode}
%
% \begin{macro}{\snap@restore@extensions}
% We need the following patch to make up for the fact that
% \cs{@pkgextension} and \cs{@clsextension} are marked in the \latex/
% kernel as \qq{only preamble}.
% \begin{macrocode}
\edef\snap@restore@extensions{%
\def\@nx\@pkgextension{\@pkgextension}%
\def\@nx\@clsextension{\@clsextension}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@pad}
% Pad filename strings out to 8+3 length so that the list will look
% pretty.
% \begin{macrocode}
\def\snap@pad#1#2#3#4#5#6#7#8#9{\snap@pad@a{#1#2#3#4#5#6#7#8#9}}
\def\snap@pad@a#1#2#3#4#5\@nil{\snap@pad@b#1#2#3#4\space\@nil}
\def\snap@pad@b#1\space#2\@nil#3{\def#3{#2}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@trim@version}
% First stage: discard leading spaces before the first and second
% nonspace strings in the argument. Take the first nonspace string as
% the date. Since we only do equal/not-equal testing on dates, it
% does not seem essential to test if it is really a valid date string
% or not (yyyy/mm/dd).
% \begin{macrocode}
\def\snap@trim@version#1#2 #3{#1#2 \snap@trim@b #3}
% \end{macrocode}
% Second stage: Scan for a version number. In order to handle some
% idiosyncratic cases, such as url.sty version 1.4, we can't simply
% take the second nonspace string as the version number but need to
% look for a leading digit.
% \begin{macrocode}
\def\snap@trim@b#1{\ifodd 0#11 v#1\@xp\snap@trim@c\fi \snap@trim@b}
% \end{macrocode}
% Arg 1 here is \cs{snap@trim@b}, which we just need to discard.
% \begin{macrocode}
\def\snap@trim@c#1#2 #3\@nil{#2}
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
\let\rqv@list=\@empty
% \end{macrocode}
%
% If \verb'\fmtname.fmt' is not already in the file list, add it.
% \begin{macrocode}
\edef\@tempc#1\fmtname{#1\fmtname}\@tempc
\def\@tempa#1,\fmtname.fmt,#2#3\@nil{#2}
\edef\@tempb{\@nx\@tempa,\@filelist,\fmtname.fmt,}
\if ?\@tempb?\@nil
\edef\@filelist{\fmtname.fmt,\@filelist}%
\def\@tempc{LaTeX2e}%
\@xp\edef\csname ver@\fmtname.fmt\endcsname{%
\fmtversion\space
v\ifx\@tempc\fmtname 2.e\else ?.?\fi
}%
\fi
% \end{macrocode}
% Ensure that files get recorded.
% \begin{macrocode}
\listfiles
% \end{macrocode}
%
% \begin{macro}{\snap@doit}
% \begin{macrocode}
\def\snap@doit#1{%
\begingroup
\ifx\delimiter#1\delimiter \else
\filename@parse{#1}%
\let\@tempd\@empty
\ifx\filename@ext\relax
\def\@tempa{file}\def\@tempb{~~~}%
\else\ifx\filename@ext\@pkgextension
\def\@tempa{package}\let\@tempb\@empty
\else\ifx\filename@ext\@clsextension
\def\@tempa{class}\def\@tempb{~~}%
\else\ifx\filename@ext\@fmtextension
\def\@tempa{format}\def\@tempb{~}%
\else\ifx\filename@ext\@tfmextension
\def\@tempa{tfm}\def\@tempb{~~~~}%
\else
\def\@tempa{file}%
\edef\@tempd{.\filename@ext}%
\def\@tempb{~~~}%
\fi\fi\fi\fi\fi
\@xp\let\@xp\@tempe
\csname ver@\filename@base %
\ifx\filename@ext\relax\else.\filename@ext\fi\endcsname
\ifx\@tempe\@empty \let\@tempe\relax \fi
\edef\@tempe{%
\ifx\@tempe\relax 0000/00/00 v0.0%
\else
\@xp\@xp\@xp\snap@trim@version\@xp\@tempe\space v0.0 v0.0 \@nil
\fi
}%
\edef\@tempc{\filename@area\filename@base\@tempd}% full file name
\@xp\snap@pad\@tempc\space~~~~~~~~~~~~~~~~\@nil\@tempd
\let~\space
\snap@write{\space\space *{\@tempa}\@tempb{\@tempc}\@tempd{\@tempe}}%
\fi
\aftergroup\snap@doit
\endgroup
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@bracify}
% \begin{macrocode}
\def\snap@bracify#1#2,{%
\ifx\@empty#1\expandafter\@gobble\else {#1#2}\fi \snap@bracify
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@splitter@a}
% \begin{macrocode}
\def\snap@splitter@a{%
\iffalse{{\fi }}% close current file name, end definition
\xdef\specific@files{%
\iffalse}\fi
\specific@files
\expandafter\@gobble\string % discard one closing brace
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@fdcheck}
% \begin{macrocode}
\def\snap@fdcheck#1{%
\ifx\delimiter#1%
\@xp\@gobble
\else
\snap@fda#1\@empty.fd\@empty ?\@nil
\fi
\snap@fdcheck
}
\def\snap@fda#1.fd\@empty#2#3\@nil{%
\if ?#2%
\xdef\specific@files{\specific@files {#1}}%
\else
\xdef\general@files{\general@files {#1.fd}}%
\fi
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\general@files}
% \begin{macro}{\specific@files}
% \begin{macrocode}
\let\general@files\@empty
\let\specific@files\@empty
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SpecialInput}
% The \cn{SpecialInput} command is related to the \opt{packages-only}
% option. Apart from some ad hoc handling for \fn{.fd} files that get
% loaded on demand, all files that are input after
% \verb'\begin{document}' are put into the specific-files list, and
% all files before \verb'\begin{document}' go into the general-files
% (packages-only) list. If there is a macro file for a book (say),
% that contains definitions specific to that book, and that is loaded
% in the preamble, loading it with \cs{SpecialInput} will cause it to
% go in the specific-files list.
% \begin{macrocode}
\newcommand{\SpecialInput}[1]{%
\xdef\specific@files{\specific@files{#1}}%
\@@input#1\relax
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@dofilelist}
% Our definition of \cs{@dofilelist} does not retain much resemblance
% to the original in the \LaTeX{} kernel.
% \begin{macrocode}
\def\@dofilelist{%
\snap@restore@extensions
\xdef\general@files{\@xp\snap@bracify \@filelist \@empty,\@empty,}%
\let\snap@splitter\snap@splitter@a
\xdef\general@files{\general@files}%
\let\@tempa\specific@files
\global\let\specific@files\@empty
\@xp\snap@fdcheck\@tempa{\delimiter}%
\ifx\rqv@list\@empty \else
\rqv@compare@lists
\fi
\ifx\snap@write\typeout \else
\newwrite\snap@out
\immediate\openout\snap@out=\jobname.dep \relax
\fi
\snap@write{\string\RequireVersions\@charlb}%
\snap@write{\space\space *{application}%
\snapshotApplication
}%
\@xp\snap@doit\general@files{\delimiter\aftergroup\@gobble\@gobble}%
\ifx\specific@files\@empty \else
\snap@specific
\fi
\snap@write{\@charrb}%
\ifx\snap@write\typeout \else
\immediate\closeout\snap@out
\typeout{Dependency list written on \jobname.dep.}%
\fi
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@specific}
% \begin{macrocode}
\def\snap@specific{%
\snap@write{ \space *{-------}{Document-specific files:}{----}}%
\@xp\snap@doit\specific@files{\delimiter\aftergroup\@gobble\@gobble}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\rqv@condense}
% The \cs{rqv@compare@lists} function checks to see if any files
% are found only in the RequireVersions list or only in the
% \cs{general@files} list.
% \begin{macrocode}
\def\rqv@condense#1{%
\@xp\ifx\csname ver@#1\endcsname\N \else
\edef\L{\L{#1}}%
\@xp\let\csname ver@#1\endcsname=\N
\fi
\rqv@condense
}
\def\rqv@condend{\endcsname ?\fi
\@xp\@xp\@xp\@gobbletwo\csname @xp\iftrue}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\rqv@overloaded}
% \begin{macrocode}
\def\rqv@overloaded#1{%
\snap@mismatch{snapshot}{^^J%
File #1 loaded though not in \noexpand\RequireVersions list%
}\@ehc
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\rqv@notloaded}
% \begin{macrocode}
\def\rqv@notloaded#1{%
\snap@mismatch{snapshot}{^^J%
File #1 [\csname rqv@#1\endcsname] required but not loaded%
}\@ehc
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\rqv@set}
% \begin{macro}{\rqv@test}
% \begin{macrocode}
\def\rqv@set#1{\@xp\let\csname ver@#1\endcsname\N \rqv@set}
\def\rqv@test#1{\csname ver@#1\endcsname{#1}\rqv@test}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\rqv@compare@lists}
% \begin{macrocode}
\def\rqv@compare@lists{%
\begingroup
% \end{macrocode}
% Clear up duplicate file names (just in case) to avoid redundant
% warning messages. This should seldom be necessary in practice.
% \begin{macrocode}
\def\N{1}%
\let\L\@empty
\@xp\rqv@condense\rqv@list\rqv@condend
\global\let\rqv@list=\L
\def\N{2}%
\let\L\@empty
\@xp\rqv@condense\general@files\rqv@condend
\global\let\general@files=\L
% \end{macrocode}
% Let's make a shorthand for the code that terminates our recursion.
% \begin{macrocode}
\def\T{\@firstoftwo{\endcsname\@empty\@gobbletwo}}%
% \end{macrocode}
% Set all the loaded general files to an error function.
% \begin{macrocode}
\let\N\rqv@overloaded \@xp\rqv@set\general@files \T
% \end{macrocode}
% Set all the required files to an ignore function.
% \begin{macrocode}
\let\N\@gobble
\@xp\rqv@set\rqv@list \T
% \end{macrocode}
% Execute all the general files.
% \begin{macrocode}
\@xp\rqv@test\general@files{\endcsname\csname @gobbletwo}%
% \end{macrocode}
% And now do essentially the same thing in the reverse direction.
% \begin{macrocode}
\let\N\rqv@notloaded
\@xp\rqv@set\rqv@list \T
\let\N\@gobble
\@xp\rqv@set\general@files \T
\@xp\rqv@test\rqv@list{\endcsname\csname @gobbletwo}%
\endgroup
}
% \end{macrocode}
% \end{macro}
%
% Compensate for a bug in old versions of \fn{amsgen.sty}. This is a
% little tricky.
%
% Old version: \cs{ver@amsgen}=1996/10/29 v1.2b
%
% New version: \cs{ver@amsgen.sty}=1999/11/30 v2.0
% \begin{macrocode}
%\@namedef{ver@amsgen.sty}{1996/10/29 v1.2b}
\AtBeginDocument{%
\@ifundefined{ver@amsgen}{}{%
\@xp\let\csname ver@amsgen.sty\@xp\endcsname
\csname ver@amsgen\endcsname
}%
}
% \end{macrocode}
%
% \begin{macro}{\ProvidesFile}
% Because \cs{ProvidesFile} is used in \fn{.fd} files which are
% normally read with special catcodes, there tend to
% be problems with whitespace characters being erroneously lost from
% the second argument. Since we have to put in a \cs{snap@check} call
% anyway, while we're at it let's fix a bug of this type that
% affected some older versions of \latex/.
% \begin{macrocode}
\def\ProvidesFile#1{%
\def\snap@checker{\snap@check{#1}}%
\begingroup
\aftergroup\snap@checker
\catcode`\ 10
% \end{macrocode}
% Added guards from 2001/06/01 version of \latex/. These are
% necessary because, for example, \pkg{inputenc} sets
% \cs{endlinechar} to a large (nonvalid character) value when
% reading input encoding files. The guards prevent an ``invalid
% character'' error.
% \begin{macrocode}
\ifnum\endlinechar < 256
\ifnum \endlinechar>\m@ne
\catcode\endlinechar 10
\fi
\fi
\@makeother\/%
\@makeother\&%
\kernel@ifnextchar[{\snap@providesfile{#1}}{\snap@providesfile{#1}[]}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@graphic@test}
% Normally the string found in the second arg of \cs{ProvidesFile}
% (for a nongraphics file) would begin with the usual date string.
% The \cs{includegraphics} command, however, begins the second arg
% with \texttt{Graphic file} instead. This test therefore just checks
% if the first two letters are \texttt{Gr}; this is enough,
% ordinarily, for us to conclude that we are dealing with a graphic
% file.
% \begin{macrocode}
\def\snap@graphic@test#1#2#3\@nil{r\if G#1#2\else X\fi}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@providesfile}
% \begin{macrocode}
\def\snap@providesfile#1[#2]{%
\wlog{File: #1 #2}%
% \end{macrocode}
% Adopt a suggestion made by user egrep on the \TeX\ stack exchange
% (\url{https://tex.stackexchange.com/questions/508985}) but
% without the use of the \cs{expanded} extension. This makes it
% more likely that \pkg{snapshot} can deal with macros inside the
% optional arguments of \cs{Provides...} commands.
% \begin{macrocode}
\edef\@tempa{#2}%
\if\@xp\snap@graphic@test\@tempa @@\@nil
\snap@record@graphic#1\relax #2 (type ??)\@nil
\else
\@xp\xdef\csname ver@#1\endcsname{#2}%
\fi
\endgroup
}
% \end{macrocode}
% \end{macro}
%
% This is what \cn{includegraphics} does to record graphic file
% information.
%\begin{verbatim}
%\@providesfile #1[#2]->
%\wlog {File: #1 #2}\expandafter \xdef \csname ver@#1\endcsname {#2}
%\endgroup
%#1<-\Gin@base \Gin@ext
%#2<-Graphic file (type eps)
%\end{verbatim}
%
% \begin{macro}{\snap@record@graphic}
% Check the graphics info.
% \begin{macrocode}
\def\snap@record@graphic#1\relax #2(type #3)#4\@nil{%
\expandafter\xdef\csname ver@#1\endcsname{%
Graphic%
\if\snap@bbinfo :bb=\Gin@llx/\Gin@lly/\Gin@urx/\Gin@ury\fi
\space v0.0%
}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@pr@videpackage}
% \begin{macrocode}
\def\@pr@videpackage [#1]{%
\expandafter\xdef\csname ver@\@currname.\@currext\endcsname{#1}%
\ifx\@currext\@clsextension
\typeout{Document Class: \@gtempa\space#1}%
\else
\wlog{Package: \@gtempa\space#1}%
\fi
\snap@check{\@currname.\@currext}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@selfcheck@a}
% \begin{macrocode}
\def\snap@selfcheck@a{\snap@check{snapshot.sty}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@nofmt}
% \begin{macrocode}
\def\@nofmt#1.fmt.#2 {#1 }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@mismatch@a}
% \begin{macrocode}
\def\snap@mismatch@a#1#2#3{%
\snap@mismatch{snapshot}{^^J%
\space\space Required version #2 of \@nofmt#1.fmt. and^^J%
\space\space provided version #3 do not match%
}\@ehc
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@compare@versions}
% When comparing \cs{rqv@foo.sty} (information from a previous
% \latex/ run) with \cs{ver@foo.sty} (information from current run),
% we first call \cs{snap@trim@version} on the latter to clear away
% any idiosyncrasies in the contents.
% \begin{macrocode}
\def\snap@compare@versions#1{%
\begingroup
\@ifundefined{rqv@#1}{}{%
\edef\0{\csname rqv@#1\endcsname}%
\edef\1{\csname ver@#1\endcsname}%
\edef\1{\@xp\snap@trim@version\1 v0.0 v0.0 \@nil}%
\edef\@tempa{\@xp\snap@select\0 v0.0 v0.0 \@nil}%
\edef\@tempb{\@xp\snap@select\1 v0.0 v0.0 \@nil}%
\ifx\@tempa\@tempb \else
\edef\@tempd{\@nx\snap@mismatch@a{#1}{\@tempa}{\@tempb}}%
\@xp\@tempd
\fi
}%
\endgroup
% \end{macrocode}
% When the \opt{test} option is in effect, jump out of the current
% file instead of continuing.
% \begin{macrocode}
\snap@test@abort
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@test@abort}
% \begin{macrocode}
\let\snap@test@abort=\@empty
% \end{macrocode}
% \end{macro}
%
% \section{Compatibility}
%
% Suppose that I have a \lat/ document containing a
% \cs{RequireVersions} statement generated by \pkg{snapshot} and I
% send this to my colleague who, we believe, has a \lat/ setup that
% is for our purposes identical. Suppose that our belief is erroneous
% in the following way: My colleague has a newer version of
% \pkg{snapshot} and a newer version of one of the affected files.
%
% Here is what we \strong{don't} want to happen: That the differing
% version of snapshot would cause the other differing file to be
% accepted without demur.
%
% Conversely, if it is I who have the newer version of
% \pkg{snapshot}, the main concern is that some difference in the
% contents of the \cs{RequireVersions} statement would lead to an
% error when my colleague attempts to process the document.
%
% \section{In conclusion}
%
% \begin{macrocode}
\ifx\snap@select\@empty
\let\snap@compare@versions\@gobble
\let\snap@check\@gobble
\fi
% \end{macrocode}
%
% Fallback for a command that is sometimes used in AMS journal
% production.
% \begin{macrocode}
\providecommand{\controldates}[1]{}
% \end{macrocode}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% \section{And finally \dots}\label{test}
%
% If the embedded \cs{RequireVersions}
% data in a \lat/ document is extracted to a separate file, and
%\begin{verbatim}
%\RequirePackage[test]{snapshot}
%\end{verbatim}
% is added at the top, then the file can be run as a small separate
% \LaTeX{} job that will, among other things, produce in the log file
% a nice list of fully resolved file names\mdash sort of a limited,
% but system-independent variant of the \fn{kpsewhich} idea.
% \begin{macrocode}
\ifx\snap@intest\@gobbletwo \endinput \fi
% \end{macrocode}
%
% Some old, ill-behaved packages might throw in a \cs{makeatother} at
% the end which can cause problems for the next file that comes along
% when testing.
% \begin{macrocode}
\def\restore@some@catcodes{}
\def\save@some@catcodes{%
\edef\restore@some@catcodes{%
\catcode\number`\@=\number\catcode`\@
\catcode\number`\"=\number\catcode`\"
\catcode\number`\^=\number\catcode`\^
\catcode\number`\_=\number\catcode`\_
\relax
}%
}
% \end{macrocode}
%
% Some typical calls of \cs{snap@intest}:
%\begin{verbatim}
% \snap@intest{LaTeX2e}{\snapx@format}
% \snap@intest{snapshot}{\snapx@package}
% \snap@intest{mcom-l}{\snapx@class}
% \snap@intest{amsmath}{\snapx@package}
% \snap@intest{umsa.fd}{\snapx@file}
% \snap@intest{pictex}{\snapx@file}
%\end{verbatim}
%
% The extant public versions of the following files (in the teTeX
% distribution, at least) are known to be problematic when we are
% trying to read a \cs{ProvidesWhatever} line from the top of the
% file: psfig.sty, pictex.sty, pictex.tex, epic.sty, amstex.sty,
% xy.tex. Either (a) they don't have a \cs{ProvidesWhatever} line at
% all, or (b) they include some code before the \cs{ProvidesWhatever}
% line that makes some assumption true in normal processing but false
% in snapshot-test processing. E.g., there is code in \fn{amstex.sty}
% that assumes \cs{documentstyle} or \cs{documentclass} was already
% executed and that the \cs{if@compatibility} switch got set
% accordingly.
%
% \begin{macro}{\snap@intest}
% \begin{macrocode}
\def\snap@intest#1#2{%
\message{^^J}%
\begingroup
\edef\0{#1#2}%
\def\9{latex209.def}%
\ifx\0\9\global\@compatibilitytrue \fi
\ifx#2\snapx@format
% \end{macrocode}
% If arg1 + arg2 = ``LaTeX2e.fmt'', the calling function
% \cs{snap@storeb} will run \cs{snap@check} separately.
% This is a crude way of making things work in that case without
% much extra trouble.
% \begin{macrocode}
\def\snap@test@abort{\endgroup}%
\else
\edef\N{%
\noexpand\snap@intest@b{#1#2}%
{#1}{\@xp\@gobble#2\@empty}%
{\csname rqv@#1#2\endcsname}}%
\expandafter\endgroup\N
\fi
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@intest@b}
% \begin{macrocode}
\def\snap@intest@b#1#2#3#4{%
\def\@currname{#2}%
\def\@currext{#3}%
\begingroup
\lccode`\/=`\0\relax\lowercase{\endgroup
\ifnum\snap@seldate#4 00 0\@nil>\z@
}% matches \lowercase
\save@some@catcodes
\@@input #1 \relax
\restore@some@catcodes
\else
\snap@specialtest{#1}{#4}%
\fi
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\snap@specialtest}
% \begin{macrocode}
\def\snap@specialtest#1#2{%
\fake@input{#1}%
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\fake@input}
% \begin{macrocode}
\def\fake@input#1{%
\begingroup
% Ensure that outer \foo or unmatched braces don't trip us up
\catcode`\\=12
\catcode`\{=12
\catcode`\}=12
\endinput
% \end{macrocode}
% Note that these definitions of \cs{G} and \cs{?} are local, and
% recall that one-letter cs names don't use up hash table entries.
% \begin{macrocode}
\def\G{\@car\endgroup}%
\expandafter\futurelet\expandafter\?\expandafter\G\@@input#1 \relax\@nil
}
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
\let\snap@test@abort=\endinput
\let\snap@selfcheck=\@empty
% \end{macrocode}
%
% \begin{macro}{\snap@finish}
% There's an extra close-brace left hanging around at the end, but I
% guess we don't care.
% \begin{macrocode}
\def\snap@finish{%%
\endgroup
\message{^^J}%
\def\X##1{##1,\X}%
\edef\@filelist{\@xp\X\rqv@list{\@gobbletwo}}%
\def\X##1,?{##1}\edef\@filelist{\@xp\X\@filelist ?}%
\@dofilelist
\@@end
}
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
\def\snap@mismatch#1#2#3{}
% \end{macrocode}
%
% Problematic: xy.sty, because it calls xy.tex before it calls
% \cs{ProvidesPackage}. And pictex.tex because it doesnt use
% \cs{ProvidesFile} at all.
% \begin{macrocode}
\renewcommand{\RequireVersions}[2][]{%
\begingroup
\makeatletter
\def\snap@check{\snap@compare@versions}%%
\let\snapx@tfm=\snap@ignore
% \end{macrocode}
% This seems to help, with english.ldf for example, to prevent an
% endless loop when attempting to load babel.def.
% \begin{macrocode}
\def\ProvidesLanguage##1{\ProvidesFile{##1.ldf}}%
\iffalse{\fi \futurelet\@let@token\snap@branch #2}%
\endgroup
}
% \end{macrocode}
%
% \section{Finale}
%
% The usual \cs{endinput} to ensure that random garbage at the end of
% the file doesn't get copied by \fn{docstrip}.
% \begin{macrocode}
\endinput
% \end{macrocode}