path: root/Master/texmf-dist/source/latex/base/ltmiscen.dtx

% \iffalse meta-comment
%
% Copyright 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
% The LaTeX3 Project and any individual authors listed elsewhere
% in this file. 
% 
% This file is part of the LaTeX base system.
% -------------------------------------------
% 
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    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 file has the LPPL maintenance status "maintained".
% 
% The list of all files belonging to the LaTeX base distribution is
% given in the file `manifest.txt'. See also `legal.txt' for additional
% information.
% 
% The list of derived (unpacked) files belonging to the distribution 
% and covered by LPPL is defined by the unpacking scripts (with 
% extension .ins) which are part of the distribution.
% 
% \fi
% \iffalse
%%% From File: ltmiscen.dtx
%
%<*driver>
% \fi
\ProvidesFile{ltmiscen.dtx}
             [2000/07/11 v1.1j LaTeX Kernel (Misc. Environments)]
% \iffalse
\documentclass{ltxdoc}
\GetFileInfo{ltmiscen.dtx}
\title{\filename}
\date{\filedate}
 \author{%
  Johannes Braams\and
  David Carlisle\and
  Alan Jeffrey\and
  Leslie Lamport\and
  Frank Mittelbach\and
  Chris Rowley\and
  Rainer Sch\"opf}

\begin{document}
\maketitle
 \DocInput{\filename}
\end{document}
%</driver>
% \fi
%
% \CheckSum{457}
%
% \changes{v1.0c}{1994/03/28}{Improve Documentation}
% \changes{v1.0d}{1994/03/29}{Remove counter macros to ltcntlen}
% \changes{v1.0g}{1994/05/02}{Changed 91 to 1991 and moved some bits}
% \changes{v1.0i}{1994/05/05}{Removed braces from ifnextchar and
% ifstar arguments}
% \changes{v1.0m}{1994/05/20}{Use new warning commands}
% \changes{v1.0n}{1994/05/21}{Use new error commands}
% \changes{v1.0s}{1994/10/14}{Move math to other file}
% \changes{v1.0v}{1994/11/17}
%         {\cs{@tempa} to \cs{reserved@a}}
% \changes{v1.0x}{1995/04/22}{Removed extra def of \cs{@gobble}}
% \changes{v1.0z}{1995/07/13}{Improve Documentation}
% \changes{v1.1c}{1996/04/22}{Improve Documentation}
% \changes{v1.1d}{1996/06/03}{Move setting of verbatim font and
%         \cs{@noligs}.}
% \changes{v1.1g}{1998/08/17}{(RmS) Minor documentation fixes.}
%
% \section{Miscellaneous Environments}
%  This section implements the basic environment mechanism, and also 
% a few specific environments including |document|, The math
% environments and related commands, the `flushing' environments,
% (|center|, |flushleft|, |flushright|), and |verbatim|.
%
% \StopEventually{}
%
%    \begin{macrocode}
%<*2ekernel>
\message{environments,}
%    \end{macrocode}
%
% \subsection{Environments}
%
%  |\begin{foo}| and |\end{foo}| are used to delimit environment |foo|.
%
%  |\begin{foo}| starts a group and calls |\foo| if it is defined,
%  otherwise it does nothing.
%
% |\end{foo}| checks to see that it matches the
%  corresponding |\begin| and if so, it calls |\endfoo| and does an
%  |\endgroup|.  Otherwise, |\end{foo}| does nothing.
%
%  If |\end{foo}| needs to ignore blanks after it, then |\endfoo| should
%  globally set the |@ignore| switch true with |\@ignoretrue| 
%  (this will automatically be global).
%
%
%  NOTE: |\@@end| is defined to be the |\end| command of \TeX82.
%
%  |\enddocument| is the user's command for ending the manuscript file.
%
%  |\stop| is a panic button --- to end \TeX\ in the middle.
%
% \begin{oldcomments}
% \enddocument ==
%   BEGIN
%    \@checkend{document}   %% checks for unmatched \begin
%    \clearpage
%    \begingroup
%      if @filesw = true
%        then  close file @mainaux
%              if G@refundefined = true
%               then LaTeX Warning: 'There are undefined references.' fi
%              if @multiplelabels = true
%                then LaTeX Warning: 
%                    'One or more label(s) multiply defined.'
%                else
%                \@setckpt {ARG1}{ARG2} == null
%                \newlabel{LABEL}{VAL} ==
%                    BEGIN
%                      \reserved@a == VAL
%                      if def(\reserved@a) = def(\r@LABEL)
%                        else @tempswa := true          fi
%                    END
%                \bibcite{LABEL}{VAL} == null
%                    BEGIN
%                      \reserved@a == VAL
%                      if def(\reserved@a) = def(\g@LABEL)
%                        else @tempswa := true          fi
%                    END
%                @tempswa := false
%                make @ a letter
%                \input \jobname.AUX
%                if @tempswa = true
%                  then LaTeX Warning: 'Label may have changed.
%                                  Rerun to get cross-references right.'
%       fi     fi     fi
%    \endgroup
%    finish up
%   END
%
%  \@writefile{EXT}{ENTRY} ==
%      if tf@EXT undefined
%        else \write\tf@EXT{ENTRY}
%      fi
% \end{oldcomments}
%
% \begin{macro}{\@currenvir}
%    The name of the current environment.  Initialized to
%    \texttt{document} to so that |\end{document}| works correctly.
%    \begin{macrocode}
\def\@currenvir{document}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\if@ignore}
% \begin{macro}{\@ignoretrue}
% \begin{macro}{\@ignorefalse}
% \changes{v1.1e}{1996/07/26}{put \cs{global} into definition}
%    \begin{macrocode}
\def\@ignorefalse{\global\let\if@ignore\iffalse}
\def\@ignoretrue {\global\let\if@ignore\iftrue}
\@ignorefalse
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\ignorespacesafterend}
% \changes{v1.1e}{1996/07/26}{user level macro added}
%    \begin{macrocode}
\let\ignorespacesafterend\@ignoretrue 
%    \end{macrocode}
% \end{macro}
%
%  \begin{macro}{\enddocument}
% \changes{LaTeX2.09}{1993/08/03}
%         {Changed redefinition of \cs{global} to redefinition
%               of \cs{@setckpt}.}
% \changes{LaTeX2.09}{1993/09/08}
%         {Added warning in case of undefined references.}%    
% \changes{v0.9e}{1993/12/09}{Hook added}
%    \begin{macrocode}
\def\enddocument{%
%    \end{macrocode}
%    The |\end{document}| hook is executed first. If necessary it can
%    contain a |\clearpage| to output dangling floats first. In this
%    position it can also contain something like |\end{foo}| so that
%    the whole document effectively starts and ends with some special
%    environment. However, this must be used with care, eg if two
%    applications would use this without knowledge of each other the
%    order of the environments will be wrong after all. 
%    |\AtEndDocument| is redefined
%    at this point so that and such commands that get into the hook do
%    not chase their tail\ldots
% \changes{v1.0y}{1995/04/27}{\cs{@checkend} moved after hook}
% \changes{v1.0z}{1995/07/13}{Set \cs{@setckpt} to \cs{@gobbletwo}
%                    instead of defining it by hand}
% \changes{v1.1i}{2000/05/19}
%            {Reset \cs{AtEndDocument} for latex/3060}
%    \begin{macrocode}
   \let\AtEndDocument\@firstofone
   \@enddocumenthook
   \@checkend{document}%
   \clearpage
   \begingroup
     \if@filesw
       \immediate\closeout\@mainaux
       \let\@setckpt\@gobbletwo
       \let\@newl@bel\@testdef
%    \end{macrocode}
% \changes{v1.0z}{1995/07/13}{Sorten redefinition of \cs{bibcite} and
%          \cs{newlabel}}
%    The previous line is equiv to setting
%\begin{verbatim}
%       \def\newlabel{\@testdef r}%
%       \def\bibcite{\@testdef b}%
%\end{verbatim}
%    \begin{macrocode}
       \@tempswafalse 
       \makeatletter \input\jobname.aux
     \fi
%    \end{macrocode}
% \changes{v1.0w}{1994/11/30}
%         {(DPC) Use \cs{@dofilelist}}
%    \begin{macrocode}
     \@dofilelist
%    \end{macrocode}
%    First we check for font size substitution bigger than
%    |\fontsubfuzz|. The |\relax| is necessary because this is a macro
%    not a register.
% \changes{v1.0w}{1994/11/30}
%         {(DPC) Do warnings even for \cs{nofiles}}
%    \begin{macrocode}
     \ifdim \font@submax >\fontsubfuzz\relax
%    \end{macrocode}
%    In case you wonder about the |\@gobbletwo| inside the message
%    below, this is a horrible hack to remove the tokens |\on@line.|
%    that are added by |\@font@warning| at the end.
% \changes{v1.1j}{2000/07/11}{Fix typo in warning}
%    \begin{macrocode}
       \@font@warning{Size substitutions with differences\MessageBreak
                  up to \font@submax\space have occurred.\@gobbletwo}%
     \fi
%    \end{macrocode}
%    The macro |\@defaultsubs| is initially |\relax| but gets redefined
%    to produce
%    a warning if there have been some default font substitutions.
% \changes{v1.0z}{1995/07/13}{Use \cs{@defaultsubs} instead of switch}
%    \begin{macrocode}
     \@defaultsubs
%    \end{macrocode}
%    The macro |\@refundefined| is initially |\relax| but gets redefined
%    to produce a warning if there are undefined refs.
% \changes{v1.1b}{1995/10/24}{Use \cs{@refundefined} instead of switch}
%    \begin{macrocode}
     \@refundefined
%    \end{macrocode}
%    If a label is defined more than once, |\@tempswa| will always be
%    true and thus produce a ``Label(s) may \ldots'' warning. But
%    since a rerun will not solve that problem (unless one uses a
%    package like \texttt{varioref} that generates labels on the fly),
%    we suppress this message.
% \changes{v1.0e}{1994/04/20}{Changed logic for producing 
%                             warning messages}
% \changes{v1.1b}{1995/10/24}{Changed logic for producing 
%                             warning messages and removed switch}
%    \begin{macrocode}
     \if@filesw
       \ifx \@multiplelabels \relax
         \if@tempswa
           \@latex@warning@no@line{Label(s) may have changed.
               Rerun to get cross-references right}%
         \fi
       \else
         \@multiplelabels 
       \fi
     \fi
   \endgroup
   \deadcycles\z@\@@end}
%    \end{macrocode}
%  \end{macro}
%
% \begin{macro}{\@testdef}
%    \begin{macrocode}
\def\@testdef #1#2#3{%
  \def\reserved@a{#3}\expandafter \ifx \csname #1@#2\endcsname
 \reserved@a  \else \@tempswatrue \fi}
%    \end{macrocode}
%  \end{macro}
%
%
% \begin{macro}{\@writefile}
% \changes{v1.0l}{1994/05/20}{Added correct setting of \cs{protect}.}
% \changes{v1.0t}{1994/11/04}{Removed setting of \cs{protect}. ASAJ.}
% \changes{v1.0z}{1995/07/13}{Added missing percent and use \cs{relax}
%  in the THEN case}
%    \begin{macrocode}
\long\def\@writefile#1#2{%
  \@ifundefined{tf@#1}\relax
    {\@temptokena{#2}%
     \immediate\write\csname tf@#1\endcsname{\the\@temptokena}%
    }%
}
%    \end{macrocode}
%  \end{macro}
%
% \begin{macro}{\stop}
%    \begin{macrocode}
\def\stop{\clearpage\deadcycles\z@\let\par\@@par\@@end}
%    \end{macrocode}
%  \end{macro}
%
%
% \begin{oldcomments}
%
%    \begin{macrocode}
\everypar{\@nodocument} %% To get an error if text appears before the
\nullfont               %% \begin{document}
%    \end{macrocode}
%
% \begin, \end, and \@checkend changed so \end{document} will catch
% an unmatched \begin.  Changed 24 May 89 as suggested by
% Frank Mittelbach and Rainer Sch\"opf.
%
% \begin{NAME} ==
%  BEGIN
%    IF \NAME undefined  THEN  \reserved@a == BEGIN report error END
%                        ELSE  \reserved@a ==  
%                                   (\@currenvir :=L NAME) \NAME
%    FI
%    @ignore :=G F      %% Added 30 Nov 88
%    \begingroup
%    \@endpe := F
%    \@currenvir :=L NAME
%    \NAME
%  END
%
% \end{NAME} ==
%  BEGIN
%   \endNAME
%   \@checkend{NAME}
%   \endgroup
%   IF @endpe = T              %% @endpe set True by \@endparenv
%     THEN \@doendpe           %% \@doendpe redefines \par and \everypar
%                              %% to suppress paragraph indentation in
%   FI                         %% immediately following text
%   IF @ignore = T
%     THEN @ignore :=G F
%          \ignorespaces
%   FI
%  END
%
% \@checkend{NAME} ==
%  BEGIN
%   IF \@currenvir = NAME
%     ELSE \@badend{NAME}
%   FI
%  END
%
% \end{oldcomments}
%
%
% \begin{macro}{\begin}
% \changes{LaTeX2.09}{1992/03/18}{Changed \cs{@ignoretrue} to
%               \cs{@ignorefalse} (as documented)}
% \changes{LaTeX2.09}{1992/08/24}{Added code to \cs{begin} to 
%      remember line number. Used by \cs{@badend} to display 
%      position of non-matching \cs{begin}.}
% \changes{v1.1e}{1996/07/26}{remove \cs{global} before \cs{@ignore...}}
%    \begin{macrocode}
\def\begin#1{%
  \@ifundefined{#1}%
    {\def\reserved@a{\@latex@error{Environment #1 undefined}\@eha}}%
    {\def\reserved@a{\def\@currenvir{#1}%
     \edef\@currenvline{\on@line}%
     \csname #1\endcsname}}%
  \@ignorefalse 
  \begingroup\@endpefalse\reserved@a}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\end}
% \changes{v1.1e}{1996/07/26}{remove \cs{global} before \cs{@ignore...}}
%    \begin{macrocode}
\def\end#1{%
  \csname end#1\endcsname\@checkend{#1}%
  \expandafter\endgroup\if@endpe\@doendpe\fi
  \if@ignore\@ignorefalse\ignorespaces\fi}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\@checkend}
%    \begin{macrocode}
\def\@checkend#1{\def\reserved@a{#1}\ifx
      \reserved@a\@currenvir \else\@badend{#1}\fi}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\@currenvline}
%    We do need a default value for |\@currenvline| on top-level since
%    the document environment cancels the brace group. This means that
%    a missmatch with |\begin|\allowbreak|{document}| will not produce
%    a line number. Thus the outer default must be |\@empty| or we
%    will end up with two spaces.
% \changes{v1.0q}{1994/05/24}{Use \cs{@empty} as outer default}
%    \begin{macrocode}
\let\@currenvline\@empty
%    \end{macrocode}
%  \end{macro}
%
%
% \subsection{Center, Flushright, Flushleft}
%
%    \begin{macrocode}
\message{center,}
%    \end{macrocode}
%
% \begin{oldcomments}
%
% \center, \flushright and \flushleft set
%   \rightskip = 0pt or \@flushglue (as appropriate)
%   \leftskip  = 0pt or \@flushglue (as appropriate)
%   \parindent = 0pt
%   \parfillskip   = 0pt. (except \flushleft)
%   \\         == \par \vskip -\parskip
%   \\[LENGTH] == \\ \vskip LENGTH
%   \\*        == \par \penalty 10000 \vskip -\parskip
%   \\*[LEN]   == \\* \vskip LENGTH
%
% They invoke the trivlist environment to handle vertical spacing before
% and after them.
%
% \centering, \raggedright and \raggedleft are the declaration analogs
% of the above.
%
% \raggedright has a more universal effect, however.  It sets
% \@rightskip := flushglue.  Every environment, like the list
% environments, 
% that set \rightskip to its 'normal' value set it to \@rightskip
%
% \end{oldcomments}
%
% \begin{macro}{\@centercr}
% \changes{v1.0h}{1994/05/03}{\cs{@badcrerr} replaced by \cs{@nolnerr}}
% \changes{v1.0z}{1995/07/13}{Use \cs{nobreak}}
%    \begin{macrocode}
\def\@centercr{\ifhmode \unskip\else \@nolnerr\fi
       \par\@ifstar{\nobreak\@xcentercr}\@xcentercr}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@xcentercr}
%    \begin{macrocode}
\def\@xcentercr{\addvspace{-\parskip}\@ifnextchar
    [\@icentercr\ignorespaces}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@icentercr}
%    \begin{macrocode}
\def\@icentercr[#1]{\vskip #1\ignorespaces}
%    \end{macrocode}
% \end{macro}
%
%
% \begin{environment}{center}
% \changes{v0.9h}{1993/12/13}{Removed optional argument of \cs{item}}
% \changes{v1.0u}{1994/11/12}{Changed end macro to \cs{def}: safer and
% consistent}
%    We use |\relax| to prevent |\item| scanning too far.
%    \begin{macrocode}
\def\center{\trivlist \centering\item\relax}
%    \end{macrocode}
%
%    \begin{macrocode}
\def\endcenter{\endtrivlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{macro}{\centering}
%    \begin{macrocode}
\def\centering{%
  \let\\\@centercr
  \rightskip\@flushglue\leftskip\@flushglue
  \parindent\z@\parfillskip\z@skip}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@rightskip}
%    \begin{macrocode}
\newskip\@rightskip \@rightskip \z@skip
%    \end{macrocode}
% \end{macro}
%
% \begin{environment}{flushleft}
% \changes{v0.9h}{1993/12/13}{Removed optional argument of \cs{item}}
% \changes{v1.0u}{1994/11/12}{Changed end macro to \cs{def}: safer and
% consistent}
%    We use |\relax| to prevent |\item| scanning too far.
%    \begin{macrocode}
\def\flushleft{\trivlist \raggedright\item\relax}
%    \end{macrocode}
%
%    \begin{macrocode}
\def\endflushleft{\endtrivlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{macro}{\raggedright}
%    \begin{macrocode}
\def\raggedright{%
  \let\\\@centercr\@rightskip\@flushglue \rightskip\@rightskip
  \leftskip\z@skip
  \parindent\z@}
%    \end{macrocode}
% \end{macro}
%
% \begin{environment}{flushright}
% \changes{v0.9h}{1993/12/13}{Removed optional argument of \cs{item}}
% \changes{v1.0u}{1994/11/12}{Changed end macro to \cs{def}: safer and
% consistent}
%    We use |\relax| to prevent |\item| scanning too far.
%    \begin{macrocode}
\def\flushright{\trivlist \raggedleft\item\relax}
%    \end{macrocode}
%
%    \begin{macrocode}
\def\endflushright{\endtrivlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{macro}{\raggedleft}
%    \begin{macrocode}
\def\raggedleft{%
  \let\\\@centercr
  \rightskip\z@skip\leftskip\@flushglue
  \parindent\z@\parfillskip\z@skip}
%    \end{macrocode}
% \end{macro}
%
%    \begin{macrocode}
\message{verbatim,}
%    \end{macrocode}
%
% \subsection{Verbatim}
%
%
%  The verbatim environment uses the fixed-width |\ttfamily| font, turns
%  blanks into spaces, starts a new line for each carrige return (or
%  sequence of consecutive carriage returns), and interprets
%  \emph{every} character literally. 
%  I.e., all special characters |\, {, $|, etc.
%   are |\catcode|'d to 'other'.
%
% The command |\verb| produces in-line verbatim text, where the argument
% is delimited by any pair of characters.  E.g., |\verb #...#| takes
%  `|...|' as its argument, and sets it verbatim in |\ttfamily| font.
%
%  The *-variants of these commands are the same, except that spaces
%  print as the \TeX{}book's space character instead of as blank spaces.
%
%  \begin{macro}{\@vobeyspaces}
%    \begin{macrocode}
{\catcode`\ =\active%
\gdef\@vobeyspaces{\catcode`\ \active\let \@xobeysp}}
%    \end{macrocode}
% \end{macro}
%
%  \begin{macro}{\@xobeysp}
% \changes{v1.0z}{1995/07/13}{Use \cs{nobreak}}
% \changes{v1.1f}{1996/09/28}{Moved to ltspace.dtx}
% \end{macro}
%
%
%  \begin{macro}{\@xverbatim}
%  \begin{macro}{\@sxverbatim}
%    \begin{macrocode}
\begingroup \catcode `|=0 \catcode `[= 1
\catcode`]=2 \catcode `\{=12 \catcode `\}=12
\catcode`\\=12 |gdef|@xverbatim#1\end{verbatim}[#1|end[verbatim]]
|gdef|@sxverbatim#1\end{verbatim*}[#1|end[verbatim*]]
|endgroup
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%  \begin{macro}{\@verbatim}
% \changes{LaTeX2.09}{1991/07/24}{Added \cs{penalty}\cs{interlinepenalty} 
%               to definition of \cs{par} so that \cs{samepage} works}
% \changes{v0.9h}{1993/12/13}{Removed optional argument of \cs{item}}
%    Real start of verbatim environment
%    We use |\relax| to prevent |\item| scanning too far.
% \changes{v0.9p}{1994/01/18}
%         {Add \cs{global}\cs{@inlabelfalse}}
% \changes{v1.0b}{1994/03/16}
%         {Remove \cs{global}\cs{@inlabelfalse} again.}
%    \begin{macrocode}
\def\@verbatim{\trivlist \item\relax 
  \if@minipage\else\vskip\parskip\fi
  \leftskip\@totalleftmargin\rightskip\z@skip
  \parindent\z@\parfillskip\@flushglue\parskip\z@skip
%    \end{macrocode}
% \changes{LaTeX2.09}{1991/08/26}{\cs{@@par} added}
%    Added |\@@par| to clear possible |\parshape| definition
%    from a surrounding list (the verbatim guru says).
% \changes{v0.9p}{1994/01/18}
%         {Only add \cs{penalty} if in hmode}
%    \begin{macrocode}
  \@@par
  \@tempswafalse 
  \def\par{%
    \if@tempswa
%    \end{macrocode}
%    A |\leavevmode| added: needed if, for example, a blank verbatim
%    line is the first thing in a list item (wow!).
% \changes{v1.0f}{1994/04/29}{\cs{leavevmode} added}
%    \begin{macrocode}
      \leavevmode \null \@@par\penalty\interlinepenalty
    \else
      \@tempswatrue
      \ifhmode\@@par\penalty\interlinepenalty\fi
    \fi}%
%    \end{macrocode}
%    To allow customization we hide the font used in a separate macro.
%  \changes{v0.9a}{1993/11/21}{use \cs{verbatim@font} instead of \cs{tt}}
%  \changes{v0.9h}{1993/12/13}{Readded \cs{@noligs}}
%  \changes{v1.1d}{1996/06/03}{Exchanged the following two code lines
%           so that \cs{dospecials} cannot reset the category code
%           of characters handled by \cs{@noligs}.}
%  \changes{v1.1h}{2000/01/07}{Disable hyphenation even if the font allows it.}
%    \begin{macrocode}
  \let\do\@makeother \dospecials
  \obeylines \verbatim@font \@noligs
  \hyphenchar\font\m@ne
%    \end{macrocode}
%    To avoid a breakpoint after the labels box, we remove the penalty
%    put there by the list macros: another use of |\unpenalty|!
% \changes{v1.0f}{1994/04/29}{Change to \cs{everypar} added}
%    \begin{macrocode}
  \everypar \expandafter{\the\everypar \unpenalty}%
}
%    \end{macrocode}
%  \end{macro}
%  
%  \begin{macro}{\verbatim}
%  \begin{macro}{\endverbatim}
%    (RmS 93/09/19) Protected against `missing item' error message
%               triggered by empty verbatim environment.
%    \begin{macrocode}
\def\verbatim{\@verbatim \frenchspacing\@vobeyspaces \@xverbatim}
\def\endverbatim{\if@newlist \leavevmode\fi\endtrivlist}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%
%  \begin{macro}{\verbatim@font}
% \changes{v0.9a}{1993/11/21}{Macro added}
%    Macro to select the font  used for verbatim typesetting.
%    It also does other work if necessary for the font used.
% \changes{v0.9s}{1994/01/21}{Removed unnecessary category code 
%                            hackery.}
%    \begin{macrocode}
\def\verbatim@font{\normalfont\ttfamily}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{environment}{verbatim*}
%    \begin{macrocode}
\@namedef{verbatim*}{\@verbatim\@sxverbatim}
\expandafter\let\csname endverbatim*\endcsname =\endverbatim
%    \end{macrocode}
%  \end{environment}
%
%  \begin{macro}{\@makeother}
%    \begin{macrocode}
\def\@makeother#1{\catcode`#112\relax}
%    \end{macrocode}
%  \end{macro}
%
% \begin{macro}{\verb@balance@group}
% \changes{LaTeX2.09}{1993/09/07}
%     {(RmS) Changed definition of \cs{verb} so that it detects a
%              missing second delimiter.}
%    \begin{macrocode}
\let\verb@balance@group\@empty
%    \end{macrocode}
%  \end{macro}
%
% \begin{macro}{\verb@egroup}
%    \begin{macrocode}
\def\verb@egroup{\global\let\verb@balance@group\@empty\egroup}
%    \end{macrocode}
%  \end{macro}
%
% \begin{macro}{\verb@eol@error}
%    \begin{macrocode}
\begingroup
  \obeylines%
  \gdef\verb@eol@error{\obeylines%
    \def^^M{\verb@egroup\@latex@error{%
            \noexpand\verb ended by end of line}\@ehc}}%
\endgroup
%    \end{macrocode}
% \end{macro}
%
%  \begin{macro}{\verb}
% \changes{LaTeX2.09}{1992/08/24}
%         {Changed \cs{verb} and \cs{@sverb} to work correctly 
%            in math mode}
% \changes{v0.9a}{1993/11/21}{Use \cs{verbatim@font} instead of
%                             \cs{tt}.}
% \changes{v1.1a}{1995/09/19}{Put \cs{@noligs} after
%                    \cs{verbatim@font} where it belongs.}
%    Typesetting a small piece verbatim.
%  \changes{v1.1d}{1996/06/03}{Put setting of verbatim font after
%           \cs{dospecials}
%           so that \cs{dospecials} cannot reset the category code
%           of characters handled by \cs{@noligs}.}
%    \begin{macrocode}
\def\verb{\relax\ifmmode\hbox\else\leavevmode\null\fi
  \bgroup
    \verb@eol@error \let\do\@makeother \dospecials
    \verbatim@font\@noligs
    \@ifstar\@sverb\@verb}
%    \end{macrocode}
%  \end{macro}
%
%
% \begin{macro}{\@sverb}
% \changes{v1.0j}{1994/05/10}{Slight change in error message text.}
% Definitions of |\@sverb| and |\@verb| changed so |\verb+ foo+|
% does not lose leading blanks when it comes at the beginning of a line.
% Change made 24 May 89. Suggested by Frank Mittelbach and Rainer
% Sch\"opf. 
%
%    \begin{macrocode}
\def\@sverb#1{%
  \catcode`#1\active
  \lccode`\~`#1%
  \gdef\verb@balance@group{\verb@egroup
     \@latex@error{\noexpand\verb illegal in command argument}\@ehc}%
  \aftergroup\verb@balance@group
  \lowercase{\let~\verb@egroup}}%
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@verb}
%    \begin{macrocode}
\def\@verb{\@vobeyspaces \frenchspacing \@sverb}
%    \end{macrocode}
% \end{macro}
%
%  \begin{macro}{\verbatim@nolig@list}
% \changes{LaTeX2.09}{1993/09/03}
%         {Replaced \cs{@noligs} by extensible list}
%    \begin{macrocode}
\def\verbatim@nolig@list{\do\`\do\<\do\>\do\,\do\'\do\-}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\do@noligs}   
%    \begin{macrocode}
\def\do@noligs#1{%
  \catcode`#1\active
  \begingroup
     \lccode`\~`#1\relax
     \lowercase{\endgroup\def~{\leavevmode\kern\z@\char`#1}}}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\@noligs}
%    To stay compatible with packages that use |\@noligs| we keep it.
% \changes{v0.9h}{1993/12/13}{Readded \cs{@noligs}}
%    \begin{macrocode}
\def\@noligs{\let\do\do@noligs \verbatim@nolig@list}
%    \end{macrocode}
%  \end{macro}
%
% \changes{v0.9i}{1993/12/16}{\cs{literal} added}
% \changes{v1.0r}{1994/05/26/16}{\cs{literal} removed}
%    \begin{macrocode}
%</2ekernel>
%    \end{macrocode}
%
% \Finale
%