% \iffalse
%% The preview style for extracting previews from LaTeX documents.
%% Developed as part of AUCTeX .
%
% Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006,
% 2010, 2017-2019 Free Software Foundation
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 3 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the
% Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
% Boston, MA 02110-1301 USA
% \fi
% \CheckSum{1760}
% \GetFileInfo{preview.sty}
% \date{\filedate}
% \author{David Kastrup\thanks{\texttt{bug-auctex@gnu.org}}}
% \title{The \texttt{preview} Package for \LaTeX\\Version \fileversion}
% \maketitle
% \section{Introduction}
% The main purpose of this package is the extraction of certain
% environments (most notably displayed formulas) from \LaTeX\ sources
% as graphics. This works with DVI files postprocessed by either
% Dvips and Ghostscript or dvipng, but it also works when you are
% using PDF\TeX\ for generating PDF files (usually also postprocessed
% by Ghostscript).
%
% Current uses of the package include the \previewlatex\ package for
% WYSIWYG functionality in the AUC\TeX\ editing environment,
% generation of previews in LyX, as part of the operation of the
% pst-pdf package, the tbook XML system and some other tools.
%
% Producing EPS files with Dvips and its derivatives using the
% \texttt{-E} option is not a good alternative: People make do by
% fiddling around with |\thispagestyle{empty}| and hoping for the best
% (namely, that the specified contents will indeed fit on single
% pages), and then trying to guess the baseline of the resulting code
% and stuff, but this is at best dissatisfactory. The preview package
% provides an easy way to ensure that exactly one page per request
% gets shipped, with a well-defined baseline and no page decorations.
% While you still can use the preview package with the `classic'
% \begin{quote}
% |dvips -E -i|
% \end{quote}
% invocation, there are better ways available that don't rely on Dvips
% not getting confused by PostScript specials.
%
% For most applications, you'll want to make use of the |tightpage|
% option. This will embed the page dimensions into the PostScript or
% PDF code, obliterating the need to use the |-E -i| options to Dvips.
% You can then produce all image files with a single run of
% Ghostscript from a single PDF or PostScript (as opposed to EPS)
% file.
%
% Various options exist that will pass \TeX\ dimensions and other
% information about the respective shipped out material (including
% descender size) into the log file, where external applications might
% make use of it.
%
% The possibility for generating a whole set of graphics with a single
% run of Ghostscript (whether from \LaTeX\ or PDF\LaTeX) increases
% both speed and robustness of applications. It is also feasible to
% use dvipng on a DVI file with the options
% \begin{quote}
% |-picky -noghostscript|
% \end{quote}
% to omit generating any image file that requires Ghostscript, then
% let a script generate all missing files using Dvips/Ghostscript.
% This will usually speed up the process significantly.
%
% \section{Package options}
% The package is included with the customary
% \begin{quote}
% |\usepackage|\oarg{options}|{preview}|
% \end{quote}
% You should usually load this package as the last one, since it
% redefines several things that other packages may also provide.
%
% The following options are available:
% \begin{description}
% \item[|active|] is the most essential option. If this option is not
% specified, the |preview| package will be inactive and the document
% will be typeset as if the |preview| package were not loaded,
% except that all declarations and environments defined by the
% package are still legal but have no effect. This allows defining
% previewing characteristics in your document, and only activating
% them by calling \LaTeX\ as
% \begin{quote}
% \raggedright
% |latex '\PassOptionsToPackage{active}{preview}| |\input|\marg{filename}|'|
% \end{quote}
% \item[|noconfig|] Usually the file |prdefault.cfg| gets loaded
% whenever the |preview| package gets activated. |prdefault.cfg| is
% supposed to contain definitions that can cater for otherwise bad
% results, for example, if a certain document class would otherwise
% lead to trouble. It also can be used to override any settings
% made in this package, since it is loaded at the very end of it.
% In addition, there may be configuration files specific for certain
% |preview| options like |auctex| which have more immediate needs.
% The |noconfig| option suppresses loading of those option files,
% too.
% \item[|psfixbb|] Dvips determines the bounding boxes from the
% material in the DVI file it understands. Lots of PostScript
% specials are not part of that. Since the \TeX\ boxes do not make
% it into the DVI file, but merely characters, rules and specials
% do, Dvips might include far too small areas. The option |psfixbb|
% will include |/dev/null| as a graphic file in the ultimate upper
% left and lower right corner of the previewed box. This will make
% Dvips generate an appropriate bounding box.
% \item[|dvips|] If this option is specified as a class option or to
% other packages, several packages pass things like page size
% information to Dvips, or cause crop marks or draft messages
% written on pages. This seriously hampers the usability of
% previews. If this option is specified, the changes will be undone
% if possible.
% \item[|pdftex|] If this option is set, PDF\TeX\ is assumed as the
% output driver. This mainly affects the |tightpage| option.
% \item[|xetex|] If this option is set, Xe\TeX\ is assumed as the
% output driver. This mainly affects the |tightpage| option.
% \item[|displaymath|] will make all displayed math environments
% subject to preview processing. This will typically be the most
% desired option.
% \item[|floats|] will make all float objects subject to preview
% processing. If you want to be more selective about what floats to
% pass through to a preview, you should instead use the
% \cmd{\PreviewSnarfEnvironment} command on the floats you want to
% have previewed.
% \item[|textmath|] will make all text math subject to previews.
% Since math mode is used throughly inside of \LaTeX\ even for other
% purposes, this works by redefining \cmd\(, \cmd\)
% and |$| and the |math| environment (apparently some people use
% that). Only occurences of these text math delimiters in later
% loaded packages and in the main document will thus be affected.
% \item[|graphics|] will subject all \cmd{\includegraphics} commands
% to a preview.
% \item[|sections|] will subject all section headers to a preview.
% \item[|delayed|] will delay all activations and redefinitions the
% |preview| package makes until |\||begin{document}|. The purpose
% of this is to cater for documents which should be subjected to the
% |preview| package without having been prepared for it. You can
% process such documents with
% \begin{quote}
% |latex '\RequirePackage[active,delayed,|\meta{options}|]{preview}|
% |\input|\marg{filename}|'|
% \end{quote}
% This relaxes the requirement to be loading the |preview| package
% as last package.
% \item[\meta{driver}] loads a special driver file
% |pr|\meta{driver}|.def|. The remaining options are implemented
% through the use of driver files.
% \item[|auctex|] This driver will produce fake error messages at the
% start and end of every preview environment that enable the Emacs
% package \previewlatex\ in connection with AUC\TeX\ to pinpoint
% the exact source location where the previews have originated.
% Unfortunately, there is no other reliable means of passing the
% current \TeX\ input position \emph{in} a line to external
% programs. In order to make the parsing more robust, this option
% also switches off quite a few diagnostics that could be
% misinterpreted.
%
% You should not specify this option manually, since it will only be
% needed by automated runs that want to parse the pseudo error
% messages. Those runs will then use \cmd{\PassOptionsToPackage} in
% order to effect the desired behaviour. In addition,
% |prauctex.cfg| will get loaded unless inhibited by the |noconfig|
% option. This caters for the most frequently encountered
% problematic commands.
% \item[|showlabels|] During the editing process, some people like to
% see the label names in their equations, figures and the like. Now
% if you are using Emacs for editing, and in particular
% \previewlatex, I'd strongly recommend that you check out the
% Ref\TeX\ package which pretty much obliterates the need for this
% kind of functionality. If you still want it, standard \LaTeX\
% provides it with the |showkeys| package, and there is also the
% less encompassing |showlabels| package. Unfortunately, since
% those go to some pain not to change the page layout and spacing,
% they also don't change |preview|'s idea of the \TeX\ dimensions of
% the involved boxes. So if you are using |preview| for determing
% bounding boxes, those packages are mostly useless. The option
% |showlabels| offers a substitute for them.
% \item[|tightpage|] It is not uncommon to want to use the results of
% |preview| as graphic images for some other application. One
% possibility is to generate a flurry of EPS files with
% \begin{quote}
% |dvips -E -i -Pwww -o| \meta{outputfile}|.000| \meta{inputfile}
% \end{quote}
% However, in case those are to be processed further into graphic
% image files by Ghostscript, this process is inefficient since all
% of those files need to be processed one by one. In addition, it
% is necessary to extract the bounding box comments from the EPS
% files and convert them into page dimension parameters for
% Ghostscript in order to avoid full-page graphics. This is not
% even possible if you wanted to use Ghostscript in a~\emph{single}
% run for generating the files from a single PostScript file, since
% Dvips will in that case leave no bounding box information
% anywhere.
%
% The solution is to use the |tightpage| option. That way a single
% command line like
% \begin{quote}
% \raggedright
% \texttt{gs -sDEVICE=png16m -dTextAlphaBits=4 -r300
% -dGraphicsAlphaBits=4 -dSAFER -q -dNOPAUSE
% -sOutputFile=\meta{outputfile}\%d.png \meta{inputfile}.ps}
% \end{quote}
% will be able to produce tight graphics from a single PostScript
% file generated with Dvips \emph{without} use of the options
% |-E -i|, in a single run.
%
% The |tightpage| option actually also works when using the |pdftex|
% option and generating PDF files with PDF\TeX. The resulting PDF
% file has separate page dimensions for every page and can directly
% be converted with one run of Ghostscript into image files.
%
% If neither |dvips| or |pdftex| have been specified, the
% corresponding option will get autodetected and invoked.
%
% If you need this in a batch environment where you don't want to
% use |preview|'s automatic extraction facilities, no problem: just
% don't use any of the extraction options, and wrap everything to be
% previewed into |preview| environments. This is how LyX does its
% math previews.
%
% If the pages under the |tightpage| option are just too tight, you
% can adjust by setting the length |\PreviewBorder| to a different
% value by using \cmd{\setlength}. The default value is
% |0.50001bp|, which is half of a usual PostScript point, rounded
% up. If you go below this value, the resulting page size may drop
% below |1bp|, and Ghostscript does not seem to like that. If you
% need finer control, you can adjust the bounding box dimensions
% individually by changing the macro |\PreviewBbAdjust| with the
% help of |\renewcommand|. Its default value is
% \begin{quote}
% \raggedright
% |\newcommand| |\PreviewBbAdjust|
% |{-\PreviewBorder| |-\PreviewBorder|
% |\PreviewBorder| |\PreviewBorder}|
% \end{quote}
% This adjusts the left, lower, right and upper borders by the given
% amount. The macro must contain 4~\TeX\ dimensions after another,
% and you may not omit the units if you specify them explicitly
% instead of by register. PostScript points have the unit~|bp|.
% \item[|lyx|] This option is for the sake of LyX developers. It will
% output a few diagnostics relevant for the sake of LyX' preview
% functionality (at the time of writing, mostly implemented for math
% insets, in versions of LyX starting with 1.3.0).
% \item[|counters|] This writes out diagnostics at the start and the
% end of previews. Only the counters changed since the last output
% get written, and if no counters changed, nothing gets written at
% all. The list consists of counter name and value, both enclosed
% in |{}| braces, followed by a space. The last such pair is
% followed by a colon (|:|) if it is at the start of the preview
% snippet, and by a period (|.|) if it is at the end. The order of
% different diagnostics like this being issued depends on the order
% of the specification of the options when calling the package.
%
% Systems like \previewlatex\ use this for keeping counters accurate
% when single previews are regenerated.
% \item[|footnotes|] This makes footnotes render as previews, and only
% as their footnote symbol. A convenient editing feature inside of
% Emacs.
% \end{description}
% The following options are just for debugging purposes of the package
% and similar to the corresponding \TeX\ commands they allude to:
% \begin{description}
% \item[|tracingall|] causes lots of diagnostic output to appear in
% the log file during the preview collecting phases of \TeX's
% operation. In contrast to the similarly named \TeX\ command, it
% will not switch to |\errorstopmode|, nor will it change the
% setting of |\tracingonline|.
% \item[|showbox|] This option will show the contents of the boxes
% shipped out to the DVI files. It also sets |\showboxbreadth| and
% |\showboxdepth| to their maximum values at the end of loading this
% package, but you may reset them if you don't like that.
% \end{description}
% \section{Provided Commands}
% \DescribeEnv{preview} The |preview| environment causes its contents
% to be set as a single preview image. Insertions like figures and
% footnotes (except those included in minipages) will typically lead
% to error messages or be lost. In case the |preview| package has not
% been activated, the contents of this environment will be typeset
% normally.
%
% \DescribeEnv{nopreview} The |nopreview| environment will cause its
% contents not to undergo any special treatment by the |preview|
% package. When |preview| is active, the contents will be discarded
% like all main text that does not trigger the |preview| hooks. When
% |preview| is not active, the contents will be typeset just like the
% main text.
%
% Note that both of these environments typeset things as usual when
% preview is not active. If you need something typeset conditionally,
% use the \cmd{\ifPreview} conditional for it.
%
% \DescribeMacro{\PreviewMacro} If you want to make a macro like
% \cmd{\includegraphics} (actually, this is what is done by the
% |graphics| option to |preview|) produce a preview image, you put a
% declaration like
% \begin{quote}
% |\PreviewMacro[*[[!]{\includegraphics}|
% \end{quote}
% or, more readable,
% \begin{quote}
% |\PreviewMacro[{*[][]{}}]{\includegraphics}|
% \end{quote}
% into your preamble. The optional argument to \cmd{\PreviewMacro}
% specifies the arguments \cmd{\includegraphics} accepts, since this
% is necessary information for properly ending the preview box. Note
% that if you are using the more readable form, you have to enclose
% the argument in a |[{| and |}]| pair. The inner braces are
% necessary to stop any included |[]| pairs from prematurely ending
% the optional argument, and to make a single |{}|
% denoting an optional argument not get stripped away by \TeX's
% argument parsing.
%
% The letters simply mean
% \begin{description}
% \item[|*|] indicates an optional |*| modifier, as in
% |\includegraphics*|.
% \item[|[|]^^A]
% indicates an optional argument in brackets. This syntax
% is somewhat baroque, but brief.
% \item[{|[]|}] also indicates an optional argument in brackets. Be
% sure to have encluded the entire optional argument specification
% in an additional pair of braces as described above.
% \item[|!|] indicates a mandatory argument.
% \item[|\char`{\char`}|] indicates the same. Again, be sure to have
% that additional level of braces around the whole argument
% specification.
% \item[|?|\meta{delimiter}\marg{true case}\marg{false case}] is a
% conditional. The next character is checked against being equal to
% \meta{delimiter}. If it is, the specification \meta{true case} is
% used for the further parsing, otherwise \meta{false case} will be
% employed. In neither case is something consumed from the input,
% so \marg{true case} will still have to deal with the upcoming
% delimiter.
% \item[|@|\marg{literal sequence}] will insert the given sequence
% literally into the executed call of the command.
% \item[|-|] will just drop the next token. It will probably be most
% often used in the true branch of a |?| specification.
% \item[|\#|\marg{argument}\marg{replacement}] is a transformation
% rule that calls a macro with the given argument and replacement
% text on the rest of the argument list. The replacement is used in
% the executed call of the command. This can be used for parsing
% arbitrary constructs. For example, the |[]| option could manually
% be implemented with the option string |?[{#{[#1]}{[{#1}]}}{}|.
% PStricks users might enjoy this sort of flexibility.
% \item[|:|\marg{argument}\marg{replacement}] is again a
% transformation rule. As opposed to |#|, however, the result of
% the transformation is parsed again. You'll rarely need this.
% \end{description}
%
% There is a second optional argument in brackets that can be used to
% declare any default action to be taken instead. This is mostly for
% the sake of macros that influence numbering: you would want to keep
% their effects in that respect. The default action should use |#1|
% for referring to the original (not the patched) command with the
% parsed options appended. Not specifying a second optional argument
% here is equivalent to specifying~|[#1]|.
%
% \DescribeMacro{\PreviewMacro*} A similar invocation
% \cmd{\PreviewMacro*} simply throws the macro and all of its
% arguments declared in the manner above away. This is mostly useful
% for having things like \cmd{\footnote} not do their magic on their
% arguments. More often than not, you don't want to declare any
% arguments to scan to \cmd{\PreviewMacro*} since you would want the
% remaining arguments to be treated as usual text and typeset in that
% manner instead of being thrown away. An exception might be, say,
% sort keys for \cmd{\cite}.
%
% A second optional argument in brackets can be used to declare any
% default action to be taken instead. This is for the sake of macros
% that influence numbering: you would want to keep their effects in
% that respect. The default action might use |#1| for referring to
% the original (not the patched) command with the parsed options
% appended. Not specifying a second optional argument here is
% equivalent to specifying~|[]| since the command usually gets thrown
% away.
%
% As an example for using this argument, you might want to specify
% \begin{quote}
% |\PreviewMacro*[{[]}][#1{}]{\footnote}|
% \end{quote}
% This will replace a footnote by an empty footnote, but taking any
% optional parameter into account, since an optional paramter changes
% the numbering scheme. That way the real argument for the footnote
% remains for processing by \previewlatex.
%
% \DescribeMacro{\PreviewEnvironment} The macro
% \cmd{\PreviewEnvironment} works just as \cmd{\PreviewMacro} does,
% only for environments. \DescribeMacro{\PreviewEnvironment*} And the
% same goes for \cmd{\PreviewEnvironment*} as compared to
% \cmd{\PreviewMacro*}.
%
% \DescribeMacro{\PreviewSnarfEnvironment} This macro does not typeset
% the original environment inside of a preview box, but instead
% typesets just the contents of the original environment inside of the
% preview box, leaving nothing for the original environment. This has
% to be used for figures, for example, since they would
% \begin{enumerate}
% \item produce insertion material that cannot be extracted to the
% preview properly,
% \item complain with an error message about not being in outer par
% mode.
% \end{enumerate}
%
% \DescribeMacro{\PreviewOpen}
% \DescribeMacro{\PreviewClose}
% Those Macros form a matched preview pair. This is for macros that
% behave similar as \cmd{\begin} and \cmd{\end} of an environment. It
% is essential for the operation of \cmd{\PreviewOpen} that the macro
% treated with it will open an additional group even when the preview
% falls inside of another preview or inside of a |nopreview|
% environment. Similarly, the macro treated with \cmd{\PreviewClose}
% will close an environment even when inactive.
%
% \DescribeMacro{\ifPreview} In case you need to know whether
% |preview| is active, you can use the conditional \cmd{\ifPreview}
% together with |\else| and |\fi|.
%
% \StopEventually{}
% \section{The Implementation}
% Here we go: the start is somewhat obtuse since we figure out version
% number and date from RCS strings. This should really be done at
% docstrip time instead. Takers?
% \begin{macro}{\pr@version}
% \begin{macrocode}
%<*style>
%<*!active>
\NeedsTeXFormat{LaTeX2e} \def\reserved@a #1#2$#3:
#4${\xdef#1{\reserved@c #2#4 $}} \def\reserved@c #1 #2${#1}
\begingroup \catcode`\_=12
\reserved@a\pr@version $Name: release_12_2 $ \ifx\pr@version\@empty
\reserved@a\pr@version CVS-$Revision: 1.126 $ \endgroup \else
\def\next release_{} \lccode`\_=`.
\edef\next{\lowercase{\endgroup
\def\noexpand\pr@version{\expandafter\next\pr@version}}} \next \fi
\reserved@a\next $Date: 2017/04/24 13:20:00 $
\edef\next{\noexpand\ProvidesPackage{preview}%
[\next\space \pr@version\space (AUCTeX/preview-latex)]}
\next
% \end{macrocode}
% \end{macro}
% Since many parts here will not be needed as long as the package is
% inactive, we will include them enclosed with |<*active>| and
% || guards. That way, we can append all of this stuff at a
% place where it does not get loaded if not necessary.
%
%\begin{macro}{\ifPreview}
% Setting the \cmd{\ifPreview} command should not be done by the
% user, so we don't use \cmd{\newif} here. As a consequence, there
% are no \cmd{\Previewtrue} and \cmd{\Previewfalse} commands.
% \begin{macrocode}
\let\ifPreview\iffalse
%
% \end{macrocode}
%\end{macro}
%\begin{macro}{\ifpr@outer}
% We don't allow previews inside of previews. The macro
% \cmd{\ifpr@outer} can be used for checking whether we are outside
% of any preview code.
% \begin{macrocode}
%<*active>
\newif\ifpr@outer
\pr@outertrue
%
% \end{macrocode}
%\end{macro}
%
%\begin{macro}{\preview@delay}
% The usual meaning of \cmd{\preview@delay} is to just echo its
% argument in normal |preview| operation. If |preview| is inactive,
% it swallows its argument. If the |delayed| option is active, the
% contents will be passed to the \cmd{\AtBeginDocument} hook.
%\begin{macro}{\pr@advise}
% The core macro for modifying commands is \cmd{\pr@advise}. You
% pass it the original command name as first argument and what should
% be executed before the saved original command as second argument.
%\begin{macro}{\pr@advise@ship}
% The most often used macro for modifying commands is
% \cmd{\pr@advise@ship}. It receives three arguments. The first is
% the macro to modify, the second specifies some actions to be done
% inside of a box to be created before the original macro gets
% executed, the third one specifies actions after the original macro
% got executed.
%\begin{macro}{\pr@loadcfg}
% The macro \cmd{\pr@loadcfg} is used for loading in configuration
% files, unless disabled by the |noconfig| option. After discussion
% with maintainer of pst-pdf package Rolf Niepraschk (Thanks!), we
% add here a check for existence of |luatex85.sty| and load it if
% available. With this, |preview| will also work with newer |luatex|
% versions.
% \begin{macrocode}
%<*!active>
\let\preview@delay=\@gobble
\let\pr@advise=\@gobbletwo
\long\def\pr@advise@ship#1#2#3{}
\def\pr@loadcfg#1{\InputIfFileExists{#1.cfg}{}{}}
\IfFileExists{luatex85.sty}{\RequirePackage{luatex85}}{}
\DeclareOption{noconfig}{\let\pr@loadcfg=\@gobble}
% \end{macrocode}
%\begin{macro}{\pr@addto@front}
% This adds code globally to the front of a macro.
% \begin{macrocode}
\long\def\pr@addto@front#1#2{%
\toks@{#2}\toks@\expandafter{\the\expandafter\toks@#1}%
\xdef#1{\the\toks@}}
% \end{macrocode}
% \end{macro}
% These commands get more interesting when |preview| is active:
% \begin{macrocode}
\DeclareOption{active}{%
\let\ifPreview\iftrue
\def\pr@advise#1{%
\expandafter\pr@adviseii\csname pr@\string#1\endcsname#1}%
\long\def\pr@advise@ship#1#2#3{\pr@advise#1{\pr@protect@ship{#2}{#3}}}%
\let\preview@delay\@firstofone}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\pr@adviseii}
% Now \cmd{\pr@advise} needs its helper macro. In order to avoid
% recursive definitions, we advise only macros that are not yet
% advised. Or, more exactly, we throw away the old advice and only
% take the new one. We use e\TeX's \cmd{\protected} where available
% for some extra robustness.
% \begin{macrocode}
\long\def\pr@adviseii#1#2#3{\preview@delay{%
\ifx#1\relax \let#1#2\fi
\toks@{#3#1}%
\ifx\@undefined\protected \else \protected\fi
\long\edef#2{\the\toks@}}}
% \end{macrocode}
%\end{macro}
%
% The |delayed| option is easy to implement: this is \emph{not} done
% with \cmd{\let} since at the course of document processing, \LaTeX\
% redefines \cmd{\AtBeginDocument} and we want to follow that
% redefinition.
% \begin{macrocode}
\DeclareOption{delayed}{%
\ifPreview \def\preview@delay{\AtBeginDocument}\fi
}
% \end{macrocode}
%
%\begin{macro}{\ifpr@fixbb}
% Another conditional. \cmd{\ifpr@fixbb} tells us whether we want to
% surround the typeset materials with invisible rules so that Dvips
% gets the bounding boxes right for, say, pure PostScript inclusions.
%
% If you are installing this on an operating system different from
% the one |preview| has been developed on, you might want to redefine
% |\pr@markerbox| in your |prdefault.cfg| file to use a file known to
% be empty, like |/dev/null| is under Unix. Make this redefinition
% depend on \cmd{\ifpr@fixbb} since only then |\pr@markerbox| will be
% defined.
% \begin{macrocode}
\newif\ifpr@fixbb
\pr@fixbbfalse
\DeclareOption{psfixbb}{\ifPreview%
\pr@fixbbtrue
\newbox\pr@markerbox
\setbox\pr@markerbox\hbox{\special{psfile=/dev/null}}\fi
}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@graphicstype}
% The |dvips| option redefines the |bop-hook| to reset the page
% size.
% \begin{macrocode}
\let\pr@graphicstype=\z@
\DeclareOption{dvips}{%
\let\pr@graphicstype\@ne
\preview@delay{\AtBeginDvi{%
\special{!/preview@version(\pr@version)def}
\special{!userdict begin/preview-bop-level 0 def%
/bop-hook{/preview-bop-level dup load dup 0 le{/isls false def%
/vsize 792 def/hsize 612 def}if 1 add store}bind def%
/eop-hook{/preview-bop-level dup load dup 0 gt{1 sub}if
store}bind def end}}}}
% \end{macrocode}
% The |pdftex| option just sets \cmd{\pr@graphicstype}.
% \begin{macrocode}
\DeclareOption{pdftex}{%
\let\pr@graphicstype\tw@}
% \end{macrocode}
% And so does the |xetex| option.
% \begin{macrocode}
\DeclareOption{xetex}{%
\let\pr@graphicstype\thr@@}
%
% \end{macrocode}
% \end{macro}
% \subsection{The internals}
%
% Those are only needed if |preview| is active.
% \begin{macrocode}
%<*active>
% \end{macrocode}
% \begin{macro}{\pr@snippet}
% \cmd{\pr@snippet} is the current snippet number. We need a
% separate counter to \cmd{\c@page} since several other commands
% might fiddle with the page number.
% \begin{macrocode}
\newcount\pr@snippet
\global\pr@snippet=1
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@protect}
% This macro gets one argument which is unpacked and executed in
% typesetting situations where we are not yet inside of a preview.
% \begin{macrocode}
\def\pr@protect{\ifx\protect\@typeset@protect
\ifpr@outer \expandafter\expandafter\expandafter
\@secondoftwo\fi\fi\@gobble}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@protect@ship}
% Now for the above mentioned \cmd{\pr@protect@ship}. This gets
% three arguments. The first is what to do at the beginning of the
% preview, the second what to do at the end, the third is the macro
% where we stored the original definition.
%
% In case we are not in a typesetting situation,
% \cmd{\pr@protect@ship} leaves the stored macro to fend for its
% own. No better or worse protection than the original. And we
% only do anything different when \cmd{\ifpr@outer} turns out to be
% true.
% \begin{macrocode}
\def\pr@protect@ship{\pr@protect{\@firstoftwo\pr@startbox}%
\@gobbletwo}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@insert}
% \begin{macro}{\pr@mark}
% \begin{macro}{\pr@marks}
% We don't want insertions to end up on our lists. So we disable
% them right now by replacing them with the following:
% \begin{macrocode}
\def\pr@insert{\begingroup\afterassignment\pr@insertii\count@}
\def\pr@insertii{\endgroup\setbox\pr@box\vbox}
% \end{macrocode}
% Similar things hold for marks.
% \begin{macrocode}
\def\pr@mark{{\afterassignment}\toks@}
\def\pr@marks{{\aftergroup\pr@mark\afterassignment}\count@}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@box}
% \begin{macro}{\pr@startbox}
% Previews will be stored in \cmd{\box}\cmd{\pr@box}.
% \cmd{\pr@startbox} gets two arguments: code to execute immediately
% before the following stuff, code to execute afterwards. You have
% to cater for \cmd{\pr@endbox} being called at the right time
% yourself. We will use a \cmd{\vsplit} on the box later in order
% to remove any leading glues, penalties and similar stuff. For
% this reason we start off the box with an optimal break point.
% \begin{macrocode}
\newbox\pr@box
\long\def\pr@startbox#1#2{%
\ifpr@outer
\toks@{#2}%
\edef\pr@cleanup{\the\toks@}%
\setbox\pr@box\vbox\bgroup
\break
\pr@outerfalse\@arrayparboxrestore
\let\insert\pr@insert
\let\mark\pr@mark
\let\marks\pr@marks
\expandafter\expandafter\expandafter
\pr@ship@start
\expandafter\@firstofone
\else
\expandafter \@gobble
\fi{#1}}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@endbox}
% Cleaning up also is straightforward. If we have to watch the
% bounding \TeX\ box, we want to remove spurious skips. We also
% want to unwrap a possible single line paragraph, so that the box
% is not full line length. We use \cmd{\vsplit} to clean up leading
% glue and stuff, and we make some attempt of removing trailing
% ones. After that, we wrap up the box including possible material
% from \cmd{\AtBeginDvi}. If the |psfixbb| option is active, we
% adorn the upper left and lower right corners with copies of
% \cmd{\pr@markerbox}. The first few lines cater for \LaTeX\ hiding
% things like like the code for \cmd{\paragraph} in \cmd{\everypar}.
% \begin{macrocode}
\def\pr@endbox{%
\let\reserved@a\relax
\ifvmode \edef\reserved@a{\the\everypar}%
\ifx\reserved@a\@empty\else
\dimen@\prevdepth
\noindent\par
\setbox\z@\lastbox\unskip\unpenalty
\prevdepth\dimen@
\setbox\z@\hbox\bgroup\penalty-\maxdimen\unhbox\z@
\ifnum\lastpenalty=-\maxdimen\egroup
\else\egroup\box\z@ \fi\fi\fi
\ifhmode \par\unskip\setbox\z@\lastbox
\nointerlineskip\hbox{\unhbox\z@\/}%
\else \unskip\unpenalty\unskip \fi
\egroup
\setbox\pr@box\vbox{%
\baselineskip\z@skip \lineskip\z@skip \lineskiplimit\z@
\@begindvi
\nointerlineskip
\splittopskip\z@skip\setbox\z@\vsplit\pr@box to\z@
\unvbox\z@
\nointerlineskip
%\color@setgroup
\box\pr@box
%\color@endgroup
}%
% \end{macrocode}
% \begin{macro}{\pr@ship@end}
% \label{sec:prshipend}At this point, \cmd{\pr@ship@end} gets
% called. You must not under any circumstances change |\box\pr@box|
% in any way that would add typeset material at the front of it,
% except for PostScript header specials, since the front of
% |\box\pr@box| may contain stuff from \cmd{\AtBeginDvi}.
% \cmd{\pr@ship@end} contains two types of code additions: stuff
% that adds to |\box\pr@box|, like the |labels| option does, and
% stuff that measures out things or otherwise takes a look at the
% finished |\box\pr@box|, like the |auctex| or |showbox| option do.
% The former should use \cmd{pr@addto@front} for adding to this
% hook, the latter use \cmd{g@addto@macro} for adding at the end of
% this hook.
%
% Note that we shift the output box up by its height via
% \cmd{\voffset}. This has three reasons: first we make sure that
% no package-inflicted non-zero value of \cmd{\voffset} or
% \cmd{\hoffset} will have any influence on the positioning of our
% box. Second we shift the box such that its basepoint will exactly
% be at the (1in,1in)~mark defined by \TeX. That way we can
% properly take ascenders into account. And the third reason is
% that \TeX\ treats a \cmd{\hbox} and a \cmd{\vbox} differently with
% regard to the treating of its depth. Shifting \cmd{\voffset} and
% \cmd{\hoffset} can be inhibited by setting |\pr@offset@override|.
% \begin{macrocode}
\pr@ship@end
{\let\protect\noexpand
\ifx\pr@offset@override\@undefined
\voffset=-\ht\pr@box
\hoffset=\z@
\fi
\c@page=\pr@snippet
\pr@shipout
\ifpr@fixbb\hbox{%
\dimen@\wd\pr@box
\@tempdima\ht\pr@box
\@tempdimb\dp\pr@box
\box\pr@box
\llap{\raise\@tempdima\copy\pr@markerbox\kern\dimen@}%
\lower\@tempdimb\copy\pr@markerbox}%
\else \box\pr@box \fi}%
\global\advance\pr@snippet\@ne
\pr@cleanup
}
% \end{macrocode}
% \end{macro}
% \end{macro}
% Oh, and we kill off the usual meaning of \cmd{\shipout} in case
% somebody makes a special output routine. The following test is
% pretty much the same as in |everyshi.sty|. One of its implications
% is that if someone does a \cmd{\shipout} of a \emph{void} box,
% things will go horribly wrong.
% \begin{macro}{\shipout}
% \begin{macrocode}
\let\pr@shipout=\shipout
\def\shipout{\deadcycles\z@\bgroup\setbox\z@\box\voidb@x
\afterassignment\pr@shipoutegroup\setbox\z@}
\def\pr@shipoutegroup{\ifvoid\z@ \expandafter\aftergroup\fi \egroup}
% \end{macrocode}
% \end{macro}
% \subsection{Parsing commands}
% \begin{macro}{\pr@parseit}
% \begin{macro}{\pr@endparse}
% \begin{macro}{\pr@callafter}
% The following stuff is for parsing the arguments of commands we
% want to somehow surround with stuff. Usage is
% \begin{quote}
% \cmd{\pr@callafter}\meta{aftertoken}\meta{parsestring}\cmd{\pr@endparse}\\
% \qquad\meta{macro}\meta{parameters}
% \end{quote}
% \meta{aftertoken} is stored away and gets executed once parsing
% completes, with its first argument being the parsed material.
% \meta{parsestring} would be, for example for the
% \cmd{\includegraphics} macro, |*[[!|, an optional |*| argument
% followed by two optional arguments enclosed in |[]|, followed by
% one mandatory argument.
%
% For the sake of a somewhat more intuitive syntax, we now support
% also the syntax |{*[]{}}| in the optional argument. Since \TeX\
% strips redundant braces, we have to write |[{{}}]| in this syntax
% for a single mandatory argument. Hard to avoid. We use an
% unusual character for ending the parsing. The implementation is
% rather trivial.
% \begin{macrocode}
\def\pr@parseit#1{\csname pr@parse#1\endcsname}
\let\pr@endparse=\@percentchar
\def\next#1{%
\def\pr@callafter{%
\afterassignment\pr@parseit
\let#1= }}
\expandafter\next\csname pr@parse\pr@endparse\endcsname
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@parse*}
% Straightforward, same mechanism \LaTeX\ itself employs. We take
% some care not to pass potential |#| tokens unprotected through
% macros.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse*\endcsname#1\pr@endparse#2{%
\begingroup\toks@{#1\pr@endparse{#2}}%
\edef\next##1{\endgroup##1\the\toks@}%
\@ifstar{\next{\pr@parse@*}}{\next\pr@parseit}}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@parse[}
% \begin{macro}{\pr@brace}
% Copies optional parameters in brackets if present. The additional
% level of braces is necessary to ensure that braces the user might
% have put to hide a~|]| bracket in an optional argument don't get
% lost. There will be no harm if such braces were not there at the
% start.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse[\endcsname#1\pr@endparse#2{%
\begingroup\toks@{#1\pr@endparse{#2}}%
\edef\next##1{\endgroup##1\the\toks@}%
\@ifnextchar[{\next\pr@bracket}{\next\pr@parseit}}
\long\def\pr@bracket#1\pr@endparse#2[#3]{%
\pr@parseit#1\pr@endparse{#2[{#3}]}}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@parse]}
% This is basically a do-nothing, so that we may use the syntax
% |{*[][]!}| in the optional argument instead of the more concise
% but ugly |*[[!| which confuses the brace matchers of editors.
% \begin{macrocode}
\expandafter\let\csname pr@parse]\endcsname=\pr@parseit
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@parse}
% \begin{macro}{\pr@parse!}
% Mandatory arguments are perhaps easiest to parse.
% \begin{macrocode}
\long\def\pr@parse#1\pr@endparse#2#3{%
\pr@parseit#1\pr@endparse{#2{#3}}}
\expandafter\let\csname pr@parse!\endcsname=\pr@parse
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@parse?}
% \begin{macro}{\pr@parsecond}
% This does an explicit call of |\@ifnextchar| and forks into the
% given two alternatives as a result.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse?\endcsname#1#2\pr@endparse#3{%
\begingroup\toks@{#2\pr@endparse{#3}}%
\@ifnextchar#1{\pr@parsecond\@firstoftwo}%
{\pr@parsecond\@secondoftwo}}
\def\pr@parsecond#1{\expandafter\endgroup
\expandafter\expandafter\expandafter\pr@parseit
\expandafter#1\the\toks@}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@parse@}
% This makes it possible to insert literal material into the
% argument list.
% \begin{macrocode}
\long\def\pr@parse@#1#2\pr@endparse#3{%
\pr@parseit #2\pr@endparse{#3#1}}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@parse-}
% This will just drop the next token.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse-\endcsname
#1\pr@endparse#2{\begingroup
\toks@{\endgroup\pr@parseit #1\pr@endparse{#2}}%
{\aftergroup\the\aftergroup\toks@ \afterassignment}%
\let\next= }
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@parse:}
% The following is a transform rule. A macro is being defined with
% the given argument list and replacement, and the transformed
% version replaces the original. The result of the transform is
% still subject to being parsed.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse:\endcsname
#1#2#3\pr@endparse#4{\begingroup
\toks@{\endgroup \pr@parseit#3\pr@endparse{#4}}%
\long\def\next#1{#2}%
\the\expandafter\toks@\next}
% \end{macrocode}
% \end{macro}
% \edef\next{\noexpand\begin{macro}{\noexpand
% \pr@parse\string#}}
% \next
% Another transform rule, but this passes the transformed material
% into the token list.
% \begin{macrocode}
\long\expandafter\def\csname pr@parse#\endcsname
#1#2#3\pr@endparse#4{\begingroup
\toks@{#4}%
\long\edef\next##1{\toks@{\the\toks@##1}}%
\toks@{\endgroup \pr@parseit#3\pr@endparse}%
\long\def\reserved@a#1{{#2}}%
\the\expandafter\next\reserved@a}
%
% \end{macrocode}
% \end{macro}
%
% \subsection{Selection options}
% The |displaymath| option. The |equation| environments in AMS\LaTeX\
% already do too much before our hook gets to interfere, so we hook
% earlier. Some juggling is involved to ensure we get the original
% |\everydisplay| tokens only once and where appropriate.
%
% The incredible hack with |\dt@ptrue| is necessary for working around
% bug `amslatex/3425'.
% \begin{macrocode}
%<*!active>
\begingroup
\catcode`\*=11
\@firstofone{\endgroup
\DeclareOption{displaymath}{%
\preview@delay{\toks@{%
\pr@startbox{\noindent$$%
\aftergroup\pr@endbox\@gobbletwo}{$$}\@firstofone}%
\everydisplay\expandafter{\the\expandafter\toks@
\expandafter{\the\everydisplay}}}%
\pr@advise@ship\equation{\begingroup\aftergroup\pr@endbox
\def\dt@ptrue{\m@ne=\m@ne}\noindent}%
{\endgroup}%
\pr@advise@ship\equation*{\begingroup\aftergroup\pr@endbox
\def\dt@ptrue{\m@ne=\m@ne}\noindent}%
{\endgroup}%
\PreviewOpen[][\def\dt@ptrue{\m@ne=\m@ne}\noindent#1]\[%
\PreviewClose\]%
\PreviewEnvironment[][\noindent#1]{eqnarray}%
\PreviewEnvironment[][\noindent#1]{eqnarray*}%
\PreviewEnvironment{displaymath}%
}}
% \end{macrocode}
%
% The |textmath| option. Some folderol in order to define the active
% |$|
% math mode delimiter. \cmd\pr@textmathcheck is used for checking
% whether we have a single |$| or double |$$|.
% In the latter case, we enter display math (this sort of display math
% is not allowed inside of \LaTeX\ because of inconsistent spacing,
% but surprisingly many people use it nevertheless). Strictly
% speaking, this is incorrect, since not every
% |$$| actually means display math. For example, |\hbox{$$}| will
% because of restricted horizontal mode rather yield an empty text
% math formula. Since our implementation moved the sequence inside of
% a |\vbox|, the interpretation will change. People should just not
% enter rubbish like that.
% \begin{macrocode}
\begingroup
\def\next#1#2{%
\endgroup
\DeclareOption{textmath}{%
\PreviewEnvironment{math}%
\preview@delay{\ifx#1\@undefined \let#1=$%$
\fi\catcode`\$=\active
\ifx\xyreuncatcodes\@undefined\else
\edef\next{\catcode`@=\the\catcode`@\relax}%
\makeatother\expandafter\xyreuncatcodes\next\fi}%
\pr@advise@ship\(\pr@endaftergroup{}% \)
\pr@advise@ship#1{\@firstoftwo{\let#1=#2%
\futurelet\reserved@a\pr@textmathcheck}}{}}%
\def\pr@textmathcheck{\expandafter\pr@endaftergroup
\ifx\reserved@a#1{#2#2}\expandafter\@gobbletwo\fi#2}}
\lccode`\~=`\$
\lowercase{\expandafter\next\expandafter~}%
\csname pr@\string$%$
\endcsname
%
% \end{macrocode}
% \begin{macro}{\pr@endaftergroup}
% This justs ends the box after the group opened by |#1| is closed
% again.
% \begin{macrocode}
%<*active>
\def\pr@endaftergroup#1{#1\aftergroup\pr@endbox}
%
% \end{macrocode}
% \end{macro}
%
% The |graphics| option.
% \begin{macrocode}
%<*!active>
\DeclareOption{graphics}{%
\PreviewMacro[*[[!]{\includegraphics}%]]
}
% \end{macrocode}
% The |floats| option. The complications here are merely to spare us
% bug reports about broken document classes that use |\let| on
% |\endfigure| and similar. Notable culprits that have not been
% changed in years in spite of reports are |elsart.cls| and
% |IEEEtran.cls|. Complain when you are concerned.
% \begin{macrocode}
\def\pr@floatfix#1#2{\ifx#1#2%
\ifx#1\@undefined\else
\PackageWarningNoLine{preview}{%
Your document class has a bad definition^^J
of \string#1, most likely^^J
\string\let\string#1=\string#2^^J
which has now been changed to^^J
\string\def\string#1{\string#2}^^J
because otherwise subsequent changes to \string#2^^J
(like done by several packages changing float behaviour)^^J
can't take effect on \string#1.^^J
Please complain to your document class author}%
\def#1{#2}\fi\fi}
\begingroup
\def\next#1#2{\endgroup
\DeclareOption{floats}{%
\pr@floatfix\endfigure\end@float
\pr@floatfix\endtable\end@float
\pr@floatfix#1\end@dblfloat
\pr@floatfix#2\end@dblfloat
\PreviewSnarfEnvironment[![]{@float}%]
\PreviewSnarfEnvironment[![]{@dblfloat}%]
}}
\expandafter\next\csname endfigure*\expandafter\endcsname
\csname endtable*\endcsname
% \end{macrocode}
% The |sections| option. Two optional parameters might occur in
% |memoir.cls|.
% \begin{macrocode}
\DeclareOption{sections}{%
\PreviewMacro[!!!!!!*[[!]{\@startsection}%]]
\PreviewMacro[*[[!]{\chapter}%]]
}
% \end{macrocode}
% We now interpret any further options as driver files we load. Note
% that these driver files are loaded even when |preview| is not
% active. The reason is that they might define commands (like
% \cmd{\PreviewCommand}) that should be available even in case of an
% inactive package. Large parts of the |preview| package will not
% have been loaded in this case: you have to cater for that.
% \begin{macrocode}
\DeclareOption*
{\InputIfFileExists{pr\CurrentOption.def}{}{\OptionNotUsed}}
% \end{macrocode}
%
% \subsection{Preview attaching commands}
% \begin{macro}{\PreviewMacro}
% As explained above. Detect possible |*| and call appropriate
% macro.
% \begin{macrocode}
\def\PreviewMacro{\@ifstar\pr@starmacro\pr@macro}
% \end{macrocode}
% The version without |*| is now rather straightforward.
% \begin{macro}{\pr@macro}
% \begin{macro}{\pr@domacro}
% \begin{macro}{\pr@macroii}
% \begin{macro}{\pr@endmacro}
% \begin{macrocode}
\long\def\pr@domacro#1#2{%
\long\def\next##1{#2}%
\pr@callafter\next#1]\pr@endparse}
\newcommand\pr@macro[1][]{%
\toks@{\pr@domacro{#1}}%
\long\edef\next[##1]##2{%
\noexpand\pr@advise@ship{##2}{\the\toks@{##1\noexpand\pr@endbox}}{}}%
\@ifnextchar[\next\pr@macroii}
\def\pr@macroii{\next[##1]}
\long\def\pr@endmacro#1{#1\pr@endbox}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{PreviewMacro*}
% \begin{macro}{\pr@protect@domacro}
% \begin{macro}{\pr@starmacro}
% The version with |*| has to parse the arguments, then throw them
% away. Some internal macros first, then the interface call.
% \begin{macrocode}
\long\def\pr@protect@domacro#1#2{\pr@protect{%
\long\def\next##1{#2}%
\pr@callafter\next#1]\pr@endparse}}
\newcommand\pr@starmacro[1][]{\toks@{\pr@protect@domacro{#1}}%
\long\edef\next[##1]##2{%
\noexpand\pr@advise##2{\the\toks@{##1}}}%
\@ifnextchar[\next{\next[]}}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{\PreviewOpen}
% As explained above. Detect possible |*| and call appropriate macro.
% \begin{macrocode}
\def\PreviewOpen{\@ifstar\pr@starmacro\pr@open}
% \end{macrocode}
% The version without |*| is now rather straightforward.
% \begin{macro}{\pr@open}
% \begin{macrocode}
\newcommand\pr@open[1][]{%
\toks@{\pr@domacro{#1}}%
\long\edef\next[##1]##2{%
\noexpand\pr@advise##2{\begingroup
\noexpand\pr@protect@ship
{\the\toks@{\begingroup\aftergroup\noexpand\pr@endbox##1}}%
{\endgroup}}}%
\@ifnextchar[\next\pr@macroii}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\PreviewClose}
% As explained above. Detect possible |*| and call appropriate
% macro.
% \begin{macrocode}
\def\PreviewClose{\@ifstar\pr@starmacro\pr@close}
% \end{macrocode}
% The version without |*| is now rather straightforward.
% \begin{macro}{\pr@close}
% \begin{macrocode}
\newcommand\pr@close[1][]{%
\toks@{\pr@domacro{#1}}%
\long\edef\next[##1]##2{%
\noexpand\pr@advise{##2}{\the\toks@{##1\endgroup}}}%
\@ifnextchar[\next\pr@macroii}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\PreviewEnvironment}
% Actually, this ignores any syntax argument. But don't tell
% anybody. Except for the |*|~variant, it respects (actually
% ignores) any argument! Of course, we'll need to deactivate
% |\end{|\meta{environment}|}| as well.
% \begin{macrocode}
\def\PreviewEnvironment{\@ifstar\pr@starenv\pr@env}
\newcommand\pr@starenv[1][]{\toks@{\pr@starmacro[{#1}]}%
\long\edef\next##1##2{%
\the\toks@[{##2}]##1}%
\begingroup\pr@starenvii}
\newcommand\pr@starenvii[2][]{\endgroup
\expandafter\next\csname#2\endcsname{#1}%
\expandafter\pr@starmacro\csname end#2\endcsname}
\newcommand\pr@env[1][]{%
\toks@{\pr@domacro{#1}}%
\long\edef\next[##1]##2{%
\noexpand\expandafter\noexpand\pr@advise@ship
\noexpand\csname##2\noexpand\endcsname{\the\toks@
{\begingroup\aftergroup\noexpand\pr@endbox##1}}{\endgroup}}%
\@ifnextchar[\next\pr@macroii %]
}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\PreviewSnarfEnvironment}
% This is a nuisance since we have to advise \emph{both} the
% environment and its end.
% \begin{macrocode}
\newcommand{\PreviewSnarfEnvironment}[2][]{%
\expandafter\pr@advise
\csname #2\endcsname{\pr@snarfafter{#1}}%
\expandafter\pr@advise
\csname end#2\endcsname{\pr@endsnarf}}
%
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@snarfafter}
% \begin{macro}{\pr@startsnarf}
% \begin{macro}{\pr@endsnarf}
% Ok, this looks complicated, but we have to start a group in order
% to be able to hook \cmd{\pr@endbox} into the game only when
% \cmd{\ifpr@outer} has triggered the start. And we need to get our
% start messages out before parsing the arguments.
% \begin{macrocode}
%<*active>
\let\pr@endsnarf\relax
\long\def\pr@snarfafter#1{\ifpr@outer
\pr@ship@start
\let\pr@ship@start\relax
\let\pr@endsnarf\endgroup
\else
\let\pr@endsnarf\relax
\fi
\pr@protect{\pr@callafter\pr@startsnarf#1]\pr@endparse}}
\def\pr@startsnarf#1{#1\begingroup
\pr@startbox{\begingroup\aftergroup\pr@endbox}{\endgroup}%
\ignorespaces}
%
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{\pr@ship@start}
% \begin{macro}{\pr@ship@end}
% The hooks \cmd{\pr@ship@start} and \cmd{\pr@ship@end} can be added
% to by option files by the help of the \cmd{\g@addto@macro} command
% from \LaTeX, and by the \cmd{\pr@addto@front} command from
% |preview.sty| itself. They are called just before starting to
% process some preview, and just after it. Here is the policy for
% adding to them: \cmd{\pr@ship@start} is called inside of the vbox
% |\pr@box| before typeset material gets produced. It is, however,
% preceded by a break command that is intended for usage in
% \cmd{\vsplit}, so that any following glue might disappear. In
% case you want to add any material on the list, you have to precede
% it with \cmd{\unpenalty} and have to follow it with \cmd{\break}.
% You have make sure that under no circumstances any other legal
% breakpoints appear before that, and your material should
% contribute no nonzero dimensions to the page. For the policies of
% the \cmd{\pr@ship@end} hook, see the description on
% page~\pageref{sec:prshipend}.
% \begin{macrocode}
%<*!active>
\let\pr@ship@start\@empty
\let\pr@ship@end\@empty
% \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{environment}{preview}
% \begin{environment}{nopreview}
% First we write the definitions of these environments when
% |preview| is inactive. We will redefine them if |preview| gets
% activated.
% \begin{macrocode}
\newenvironment{preview}{\ignorespaces}{\ifhmode\unskip\fi}
\newenvironment{nopreview}{\ignorespaces}{\ifhmode\unskip\fi}
% \end{macrocode}
% \end{environment}
% \end{environment}
%
% We now process the options and finish in case we are not active.
% \begin{macrocode}
\ProcessOptions\relax
\ifPreview\else\expandafter\endinput\fi
%
% \end{macrocode}
% Now for the redefinition of the |preview| and |endpreview|
% environments:
% \begin{macrocode}
%<*active>
\renewenvironment{preview}{\begingroup
\pr@startbox{\begingroup\aftergroup\pr@endbox}%
{\endgroup}%
\ignorespaces}%
{\ifhmode\unskip\fi\endgroup}
\renewenvironment{nopreview}{\pr@outerfalse\ignorespaces}%
{\ifhmode\unskip\fi}
% \end{macrocode}
% We use the normal output routine, but hijack it a bit for our
% purposes to preserve \cmd{\AtBeginDvi} hooks and not get previews
% while in output: that could become rather ugly.
%
% The main work of disabling normal output relies on a \cmd{\shipout}
% redefinition.
% \begin{macro}{\pr@output}
% \begin{macrocode}
\newtoks\pr@output
\pr@output\output
\output{%
\pr@outerfalse
\let\@begindvi\@empty
\the\pr@output}
\let\output\pr@output
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@typeinfos}
% Then we have some document info that style files might want to
% output.
% \begin{macrocode}
\def\pr@typeinfos{\typeout{Preview: Fontsize \f@size pt}%
\ifnum\mag=\@m\else\typeout{Preview: Magnification \number\mag}\fi
\ifx\pdfoutput\@undefined
\ifx\XeTeXversion\@undefined \else
% FIXME: The message should not be emitted if XeTeX does not produce
% PDF. There does not seem to be a primitive for that, though.
\typeout{Preview: PDFoutput 1}%
\fi
\else
\ifx\pdfoutput\relax \else
\ifnum\pdfoutput>\z@
\typeout{Preview: PDFoutput 1}%
\fi
\fi
\fi
}
\AtBeginDocument{\pr@typeinfos}
% \end{macrocode}
% \end{macro}
% And at the end we load the default configuration file, so that it
% may override settings from this package:
% \begin{macrocode}
\pr@loadcfg{prdefault}
%
%
% \end{macrocode}
%
% \section{The option files}
% \subsection{The \texttt{auctex} option}
% The AUC\TeX\ option will cause error messages to spew. We want them
% on the terminal, but we don't want \LaTeX\ to stop its automated
% run. We delay \cmd{\nonstopmode} in case the user has any
% pseudo-interactive folderol like reading in of file names in his
% preamble. Because we are so good-hearted, we will not break this as
% long as the document has not started, but after that we need the
% error message mechanism operative.
%
% The |\nofiles| command here tries to avoid clobbering input files
% used for references and similar. It will come too late if you call
% the package with \cmd{\AtBeginDocument}, so you'll need to issue
% |\nofiles| yourself in that case. Previously, this was done
% unconditionally in the main style file, but since we don't know what
% the package may be used for, this was inappropriate.
%
% So here is the contents of the |prauctex.def| file:
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\nofiles
%\preview@delay{\nonstopmode}
% \end{macrocode}
% Ok, here comes creative error message formatting. It turns out a
% sizable portion of the runtime is spent in I/O. Making the error
% messages short is an advantage. It is not possible to convince
% \TeX\ to make shorter error messages than this: \TeX\ always wants
% to include context. This is about the shortest \ae sthetic one we
% can muster.
% \begin{macrocode}
%\begingroup
%\lccode`\~=`\-
%\lccode`\{=`\<
%\lccode`\}=`\>
%\lowercase{\endgroup
% \def\pr@msgi{{~}}}
%\def\pr@msgii{Preview:
% Snippet \number\pr@snippet\space}
%\begingroup
%\catcode`\-=13
%\catcode`\<=13
%\@firstofone{\endgroup
%\def\pr@msg#1{{%
% \let<\pr@msgi
% \def-{\pr@msgii#1}%
% \errhelp{Not a real error.}%
% \errmessage<}}}
%\g@addto@macro\pr@ship@start{\pr@msg{started}}
%\g@addto@macro\pr@ship@end{\pr@msg{ended.%
% (\number\ht\pr@box+\number\dp\pr@box x\number\wd\pr@box)}}
% \end{macrocode}
% This looks pretty baffling, but it produces something short and
% semi-graphical, namely |<-><->|. That is a macro |<| that expands
% into |<->|, where |<| and |>| are the braces around an
% \cmd{\errmessage} argument and |-| is a macro expanding to the full
% text of the error message. Cough cough. You did not really want to
% know, did you?
%
% Since over/underfull boxes are about the messiest things to parse,
% we disable them by setting the appropriate badness limits and making
% the variables point to junk. We also disable other stuff. While we
% set \cmd{\showboxbreadth} and \cmd{\showboxdepth} to indicate as
% little diagnostic output as possible, we keep them operative, so
% that the user retains the option of debugging using this stuff. The
% other variables concerning the generation of warnings and
% daignostics, however, are more often set by commonly employed
% packages and macros such as \cmd{\sloppy}. So we kill them off for
% good.
% \begin{macrocode}
%\hbadness=\maxdimen
%\newcount\hbadness
%\vbadness=\maxdimen
%\let\vbadness=\hbadness
%\hfuzz=\maxdimen
%\newdimen\hfuzz
%\vfuzz=\maxdimen
%\let\vfuzz=\hfuzz
%\showboxdepth=-1
%\showboxbreadth=-1
% \end{macrocode}
% Ok, now we load a possible configuration file.
% \begin{macrocode}
%\pr@loadcfg{prauctex}
% \end{macrocode}
% And here we cater for several frequently used commands in
% |prauctex.cfg|:
% \begin{macrocode}
%\PreviewMacro*[[][#1{}]\footnote
%\PreviewMacro*[?[{@{[]}}{}][#1]\item
%\PreviewMacro*\emph
%\PreviewMacro*\textrm
%\PreviewMacro*\textit
%\PreviewMacro*\textsc
%\PreviewMacro*\textsf
%\PreviewMacro*\textsl
%\PreviewMacro*\texttt
%\PreviewMacro*\textcolor
%\PreviewMacro*\mbox
%\PreviewMacro*[][#1{}]\author
%\PreviewMacro*[][#1{}]\title
%\PreviewMacro*\and
%\PreviewMacro*\thanks
%\PreviewMacro*[][#1{}]\caption
%\preview@delay{\@ifundefined{pr@\string\@startsection}{%
% \PreviewMacro*[!!!!!!*][#1{}]\@startsection}{}}
%\preview@delay{\@ifundefined{pr@\string\chapter}{%
% \PreviewMacro*[*][#1{}]\chapter}{}}
%\PreviewMacro*\index
% \end{macrocode}
%
% \subsection{The \texttt{lyx} option}
% The following is the option providing LyX with info for its preview
% implementation.
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\pr@loadcfg{prlyx}
%\g@addto@macro\pr@ship@end{\typeout{Preview:
% Snippet \number\pr@snippet\space
% \number\ht\pr@box\space \number\dp\pr@box \space\number\wd\pr@box}}
% \end{macrocode}
%
% \subsection{The \texttt{counters} option}
% This outputs a checkpoint. We do this by saving all counter
% registers in backup macros starting with |\pr@c@| in their name. A
% checkpoint first writes out all changed counters (previously
% unchecked counters are not written out unless different from zero),
% then saves all involved counter values. \LaTeX\ tracks its counters
% in the global variable \cmd{\cl@ckpt}.
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\def\pr@eltprint#1{\expandafter\@gobble\ifnum\value{#1}=0%
% \csname pr@c@#1\endcsname\else\relax
% \space{#1}{\arabic{#1}}\fi}
%\def\pr@eltdef#1{\expandafter\xdef
% \csname pr@c@#1\endcsname{\arabic{#1}}}
%\def\pr@ckpt#1{{\let\@elt\pr@eltprint\edef\next{\cl@@ckpt}%
% \ifx\next\@empty\else\typeout{Preview: Counters\next#1}%
% \let\@elt\pr@eltdef\cl@@ckpt\fi}}
%\pr@addto@front\pr@ship@start{\pr@ckpt:}
%\pr@addto@front\pr@ship@end{\pr@ckpt.}
% \end{macrocode}
%
% \subsection{Debugging options}
% Those are for debugging the operation of |preview|, and thus are
% mostly of interest for people that want to use |preview| for their
% own purposes. Since debugging output is potentially confusing to
% the error message parsing from AUC\TeX, you should not turn on
% |\tracingonline| or switch from |\nonstopmode| unless you are
% certain your package will never be used with \previewlatex.
%
% \paragraph{The \texttt{showbox} option} will generate diagnostic
% output for every produced box. It does not delay the resetting of
% the |\showboxbreadth| and |\showboxdepth| parameters so that you can
% still change them after the loading of the package. It does,
% however, move them to the end of the package loading, so that they
% will not be affected by the |auctex| option.
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\AtEndOfPackage{%
% \showboxbreadth\maxdimen
% \showboxdepth\maxdimen}
%\g@addto@macro\pr@ship@end{\showbox\pr@box}
% \end{macrocode}
%
% \paragraph{The \texttt{tracingall} option} is for the really heavy
% diagnostic stuff. For the reasons mentioned above, we do not want
% to change the setting of the interaction mode, nor of the
% |tracingonline| flag. If the user wants them different, he should
% set them outside of the preview boxes.
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\pr@addto@front\pr@ship@start{\let\tracingonline\count@
% \let\errorstopmode\@empty\tracingall}
% \end{macrocode}
%
% \subsection{Supporting conversions}
% It is not uncommon to want to use the results of |preview| as
% images. One possibility is to generate a flurry of EPS files with
% \begin{quote}
% |dvips -E -i -Ppdf -o| \meta{outputfile}|.000| \meta{inputfile}
% \end{quote}
% However, in case those are to be processed further into graphic
% image files by Ghostscript, this process is inefficient. One cannot
% use Ghostscript in a single run for generating the files, however,
% since one needs to set the page size (or full size pages will be
% produced). The |tightpage| option will set the page dimensions at
% the start of each PostScript page so that the output will be sized
% appropriately. That way, a single pass of Dvips followed by a
% single pass of Ghostscript will be sufficient for generating all
% images.
%
% You will have to specify the output driver to be used, either
% |dvips| or |pdftex|.
%
% \begin{macro}{\PreviewBorder}
% \begin{macro}{\PreviewBbAdjust}
% We start this off with the user tunable parameters which get
% defined even in the case of an inactive package, so that
% redefinitions and assignments to them will always work:
% \begin{macrocode}
%\ifx\PreviewBorder\@undefined
% \newdimen\PreviewBorder
% \PreviewBorder=0.50001bp
%\fi
%\ifx\PreviewBbAdjust\@undefined
% \def\PreviewBbAdjust{-\PreviewBorder -\PreviewBorder
% \PreviewBorder \PreviewBorder}
%\fi
% \end{macrocode}
% \end{macro}
% \end{macro}
% Here is stuff used for parsing this:
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\def\pr@nextbb{\edef\next{\next\space\number\dimen@}%
% \expandafter\xdef\csname pr@bb@%
% \romannumeral\count@\endcsname{\the\dimen@}%
% \advance\count@\@ne\ifnum\count@<5
% \afterassignment\pr@nextbb\dimen@=\fi}
% \end{macrocode}
% And here is the stuff that we fudge into our hook. Of course, we
% have to do it in a box, and we start this box off with our special.
% There is one small consideration here: it might come before any
% |\AtBeginDvi| stuff containing header specials. It turns out Dvips
% rearranges this amicably: header code specials get transferred to
% the appropriate header section, anyhow, so this ensures that we come
% right after the bop section. We insert the 7~numbers here: the
% 4~bounding box adjustments, and the 3~\TeX\ box dimensions. In case
% the box adjustments have changed since the last time, we write them
% out to the console.
% \begin{macrocode}
%\ifnum\pr@graphicstype=\z@
% \ifcase
% \ifx\XeTeXversion\@undefined
% \ifx\pdfoutput\@undefined \@ne\fi
% \ifx\pdfoutput\relax \@ne\fi
% \ifnum\pdfoutput>\z@ \tw@\fi \@ne
% \else \thr@@\fi
% \or \ExecuteOptions{dvips}\relax
% \or \ExecuteOptions{pdftex}\relax
% \or \ExecuteOptions{xetex}\relax\fi\fi
%\global\let\pr@bbadjust\@empty
%\pr@addto@front\pr@ship@end{\begingroup
% \let\next\@gobble
% \count@\@ne\afterassignment\pr@nextbb
% \dimen@\PreviewBbAdjust
% \ifx\pr@bbadjust\next
% \else \global\let\pr@bbadjust\next
% \typeout{Preview: Tightpage \pr@bbadjust}%
% \fi\endgroup}
%\ifcase\pr@graphicstype
%\or
% \g@addto@macro\pr@ship@end{\setbox\pr@box\hbox{%
% \special{ps::\pr@bbadjust\space
% \number\ifdim\ht\pr@box>\z@ \ht\pr@box
% \else \z@
% \fi \space
% \number\ifdim\dp\pr@box>\z@ \dp\pr@box
% \else \z@
% \fi \space
% \number\ifdim\wd\pr@box>\z@ \wd\pr@box
% \else \z@
% \fi}\box\pr@box}}
%\or
% \g@addto@macro\pr@ship@end{{\dimen@\ht\pr@box
% \ifdim\dimen@<\z@ \dimen@\z@\fi
% \advance\dimen@\pr@bb@iv
% \dimen@ii=\dimen@
% \global\pdfvorigin\dimen@
% \dimen@\dp\pr@box
% \ifdim\dimen@<\z@ \dimen@\z@\fi
% \advance\dimen@-\pr@bb@ii
% \advance\dimen@\dimen@ii
% \global\pdfpageheight\dimen@
% \dimen@\wd\pr@box
% \ifdim\dimen@<\z@ \dimen@=\z@\fi
% \advance\dimen@-\pr@bb@i
% \advance\dimen@\pr@bb@iii
% \global\pdfpagewidth\dimen@
% \global\pdfhorigin-\pr@bb@i}}
%\or
% \g@addto@macro\pr@ship@end{\dimen@\ht\pr@box
% \ifdim\dimen@<\z@ \dimen@\z@\fi
% \advance\dimen@\pr@bb@iv
% \dimen@ii=\dimen@
% \voffset=-1in
% \advance\voffset\dimen@
% \advance\voffset-\ht\pr@box
% \dimen@\dp\pr@box
% \ifdim\dimen@<\z@ \dimen@\z@\fi
% \advance\dimen@-\pr@bb@ii
% \advance\dimen@\dimen@ii
% \global\pdfpageheight\dimen@
% \global\paperheight\dimen@
% \dimen@\wd\pr@box
% \ifdim\dimen@<\z@ \dimen@=\z@\fi
% \advance\dimen@-\pr@bb@i
% \advance\dimen@\pr@bb@iii
% \global\pdfpagewidth\dimen@
% \hoffset=-1in
% \advance\hoffset-\pr@bb@i
% \let\pr@offset@override\@empty}
%\fi
% \end{macrocode}
% Ok, here comes the beef. First we fish the 7~numbers from the file
% with |token| and convert them from \TeX~|sp| to PostScript points.
% \begin{macrocode}
%\ifnum\pr@graphicstype=\@ne
%\preview@delay{\AtBeginDvi{%
% \end{macrocode}
% Backwards-compatibility. Once we are certain that dvipng-1.6 or
% later is widely used, the three following specials can be exchanged
% for the simple |\special{!/preview@tightpage true def}|
% \begin{macrocode}
% \special{!/preview@tightpage true def (%
% compatibility PostScript comment for dvipng<=1.5 }
% \special{!userdict begin/bop-hook{%
% 7{currentfile token not{stop}if
% 65781.76 div DVImag mul}repeat
% 72 add 72 2 copy gt{exch}if 4 2 roll
% neg 2 copy lt{exch}if dup 0 gt{pop 0 exch}%
% {exch dup 0 lt{pop 0}if}ifelse 720 add exch 720 add
% 3 1 roll
% 4{5 -1 roll add 4 1 roll}repeat
% < /PageOffset[7 -2 roll [1 1 dtransform exch]%
% {0 ge{neg}if exch}forall]>>setpagedevice%
% //bop-hook exec}bind def end}
% \special{!userdict (some extra code to avoid
% dvipng>=1.6 unknown special:
% 7{currentfile token not{stop}if 65781.76 div })) pop}
% \end{macrocode}
% The ``userdict'' at the start of the last special is also there to
% avoid an unknown special in dvipng<=1.6. This is the end of the
% backwards-compatibility code.
% \begin{macrocode}
% \special{!userdict begin/bop-hook{%
% preview-bop-level 0 le{%
% 7{currentfile token not{stop}if
% 65781.76 div DVImag mul}repeat
% \end{macrocode}
% Next we produce the horizontal part of the bounding box as
% \[ (1\mathrm{in},1\mathrm{in}) +
% \bigl(\min(|\wd\pr@box|,0),\max(|\wd\pr@box|,0)\bigr) \]
% and roll it to the bottom of the stack:
% \begin{macrocode}
% 72 add 72 2 copy gt{exch}if 4 2 roll
% \end{macrocode}
% Next is the vertical part of the bounding box. Depth counts in
% negatively, and we again take $\min$ and $\max$ of possible extents
% in the vertical direction, limited by 0. 720 corresponds to
% $10\,\mathrm{in}$ and is the famous $1\,\mathrm{in}$ distance away
% from the edge of letterpaper.
% \begin{macrocode}
% neg 2 copy lt{exch}if dup 0 gt{pop 0 exch}%
% {exch dup 0 lt{pop 0}if}ifelse 720 add exch 720 add
% 3 1 roll
% \end{macrocode}
% Ok, we now have the bounding box on the stack in the proper order
% llx, lly, urx, ury. We add the adjustments:
% \begin{macrocode}
% 4{5 -1 roll add 4 1 roll}repeat
% \end{macrocode}
% The page size is calculated as the appropriate differences, the page
% offset consists of the coordinates of the lower left corner, with
% those coordinates negated that would be reckoned positive in the
% device coordinate system.
% \begin{macrocode}
% < /PageOffset[7 -2 roll [1 1 dtransform exch]%
% {0 ge{neg}if exch}forall]>>setpagedevice}if%
% \end{macrocode}
% So we now bind the old definition of |bop-hook| into our new
% definition and finish it.
% \begin{macrocode}
% //bop-hook exec}bind def end}}}
%\fi
% \end{macrocode}
%
% \subsection{The \texttt{showlabels} option}
% During the editing process, some people like to see the label names
% in their equations, figures and the like. Now if you are using
% Emacs for editing, and in particular \previewlatex, I'd strongly
% recommend that you check out the Ref\TeX\ package which pretty much
% obliterates the need for this kind of functionality. If you still
% want it, standard \LaTeX\ provides it with the |showkeys| package,
% and there is also the less encompassing |showlabels| package.
% Unfortunately, since those go to some pain not to change the page
% layout and spacing, they also don't change |preview|'s idea of the
% \TeX\ dimensions of the involved boxes.
%
% So those packages are mostly useless. So we present here an
% alternative hack that will get the labels through.
% \begin{macro}{\pr@labelbox}
% This works by collecting them into a separate box which we then
% tack to the right of the previews.
% \begin{macrocode}
%\ifPreview\else\expandafter\endinput\fi
%\newbox\pr@labelbox
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@label}
% We follow up with our own definition of the \cmd{\label} macro
% which will be active only in previews. The original definition is
% stored in |\pr@@label|. |\pr@lastlabel| contains the last typeset
% label in order to avoid duplication in certain environments, and
% we keep the stuff in |\pr@labelbox|.
% \begin{macrocode}
%\def\pr@label#1{\pr@@label{#1}%
% \end{macrocode}
% Ok, now we generate the box, by placing the label below any existing
% stuff.
% \begin{macrocode}
% \ifpr@setbox\z@{#1}%
% \global\setbox\pr@labelbox\vbox{\unvbox\pr@labelbox
% \box\z@}\egroup\fi}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\ifpr@setbox}
% |\ifpr@setbox| receives two arguments, |#1| is the box into which
% to set a label, |#2| is the label text itself. If a label needs
% to be set (if it is not a duplicate in the current box, and is
% nonempty, and we are in the course of typesetting and so on), we
% are left in a true conditional and an open group with the preset
% box. If nothing should be set, no group is opened, and we get
% into skipping to the closing of the conditional. Since
% |\ifpr@setbox| is a macro, you should not place the call to it
% into conditional text, since it will not pair up with |\fi| until
% being expanded.
%
% We have some trickery involved here. |\romannumeral\z@| expands
% to empty, and will also remove everything between the two of them
% that also expands to empty, like a chain of |\fi|.
% \begin{macrocode}
%\def\ifpr@setbox#1#2{%
% \romannumeral%
% \ifx\protect\@typeset@protect\ifpr@outer\else
% \end{macrocode}
% Ignore empty labels\dots
% \begin{macrocode}
% \z@\bgroup
% \protected@edef\next{#2}\@onelevel@sanitize\next
% \ifx\next\@empty\egroup\romannumeral\else
% \end{macrocode}
% and labels equal to the last one.
% \begin{macrocode}
% \ifx\next\pr@lastlabel\egroup\romannumeral\else
% \global\let\pr@lastlabel\next
% \setbox#1\pr@boxlabel\pr@lastlabel
% \expandafter\expandafter\romannumeral\fi\fi\fi\fi
% \z@\iffalse\iftrue\fi}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@boxlabel}
% Now the actual typesetting of a label box is done. We use a small
% typewriter font inside of a framed box (the default frame/box
% separating distance is a bit large).
% \begin{macrocode}
%\def\pr@boxlabel#1{\hbox{\normalfont
% \footnotesize\ttfamily\fboxsep0.4ex\relax\fbox{#1}}}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@maketag}
% And here is a version for |amsmath| equations. They look better
% when the label is right beside the tag, so we place it there, but
% augment |\box\pr@labelbox| with an appropriate placeholder.
% \begin{macrocode}
%\def\pr@maketag#1{\pr@@maketag{#1}%
% \ifpr@setbox\z@{\df@label}%
% \global\setbox\pr@labelbox\vbox{%
% \hrule\@width\wd\z@\@height\z@
% \unvbox\pr@labelbox}%
% \end{macrocode}
% Set the width of the box to empty so that the label placement gets
% not disturbed, then append it.
% \begin{macrocode}
% \wd\z@\z@\box\z@ \egroup\fi}
% \end{macrocode}
% \end{macro}
% \begin{macro}{\pr@lastlabel}
% Ok, here is how we activate this: we clear out box and label info
% \begin{macrocode}
%\g@addto@macro\pr@ship@start{%
% \global\setbox\pr@labelbox\box\voidb@x
% \xdef\pr@lastlabel{}%
% \end{macrocode}
% The definitions above are global because we might be in any amount
% of nesting. We then reassign the appropriate labelling macros:
% \begin{macrocode}
% \global\let\pr@@label\label \let\label\pr@label
% \global\let\pr@@maketag\maketag@@@
% \let\maketag@@@\pr@maketag
%}
% \end{macrocode}
% \end{macro}
% Now all we have to do is to add the stuff to the box in question.
% The stuff at the front works around a bug in |ntheorem.sty|.
% \begin{macrocode}
%\pr@addto@front\pr@ship@end{%
% \ifx \label\pr@label \global\let\label\pr@@label \fi
% \ifx \maketag@@@\pr@maketag
% \global\let\maketag@@@\pr@@maketag \fi
% \ifvoid\pr@labelbox
% \else \setbox\pr@box\hbox{%
% \box\pr@box\,\box\pr@labelbox}%
% \fi}
% \end{macrocode}
% \subsection{The \texttt{footnotes} option}
% This is rather simplistic right now. It overrides the default
% footnote action (which is to disable footnotes altogether for better
% visibility).
% \begin{macrocode}
%\PreviewMacro[[!]\footnote %]
% \end{macrocode}
%
% \section{Various driver files}
% The installer, in case it is missing. If it is to be used via
% |make|, we don't specify an installation path, since
% \begin{quote}
% |make install|
% \end{quote}
% is supposed to cater for the installation itself.
% \begin{macrocode}
% \input docstrip
% \askforoverwritefalse
% \generate{
% \file{preview.drv}{\from{preview.dtx}{driver}}
% \usedir{tex/latex/preview}
% \file{preview.sty}{\from{preview.dtx}{style}
% \from{preview.dtx}{style,active}}
% \file{prauctex.def}{\from{preview.dtx}{auctex}}
% \file{prauctex.cfg}{\from{preview.dtx}{auccfg}}
% \file{prshowbox.def}{\from{preview.dtx}{showbox}}
% \file{prshowlabels.def}{\from{preview.dtx}{showlabels}}
% \file{prtracingall.def}{\from{preview.dtx}{tracingall}}
% \file{prtightpage.def}{\from{preview.dtx}{tightpage}}
% \file{prlyx.def}{\from{preview.dtx}{lyx}}
% \file{prcounters.def}{\from{preview.dtx}{counters}}
% \file{prfootnotes.def}{\from{preview.dtx}{footnotes}}
%