% texinfo.tex -- TeX macros to handle Texinfo files.

%

% Load plain if necessary, i.e., if running under initex.

\expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi

%

\def\texinfoversion{2003-07-28.08}

%

% Copyright (C) 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,

% 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.

%

% This texinfo.tex file 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 2, or (at

% your option) any later version.

%

% This texinfo.tex file 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 texinfo.tex file; see the file COPYING.  If not, write

% to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,

% Boston, MA 02111-1307, USA.

%

% In other words, you are welcome to use, share and improve this program.

% You are forbidden to forbid anyone else to use, share and improve

% what you give them.   Help stamp out software-hoarding!

%

% Please try the latest version of texinfo.tex before submitting bug

% reports; you can get the latest version from:

%   ftp://ftp.gnu.org/gnu/texinfo/texinfo.tex

%     (and all GNU mirrors, see http://www.gnu.org/order/ftp.html)

%   ftp://tug.org/tex/texinfo.tex

%     (and all CTAN mirrors, see http://www.ctan.org),

%   and /home/gd/gnu/doc/texinfo.tex on the GNU machines.

%

% The GNU Texinfo home page is http://www.gnu.org/software/texinfo.

%

% The texinfo.tex in any given Texinfo distribution could well be out

% of date, so if that's what you're using, please check.

%

% Send bug reports to bug-texinfo@gnu.org.  Please include including a

% complete document in each bug report with which we can reproduce the

% problem.  Patches are, of course, greatly appreciated.

%

% To process a Texinfo manual with TeX, it's most reliable to use the

% texi2dvi shell script that comes with the distribution.  For a simple

% manual foo.texi, however, you can get away with this:

%   tex foo.texi

%   texindex foo.??

%   tex foo.texi

%   tex foo.texi

%   dvips foo.dvi -o  # or whatever; this makes foo.ps.

% The extra TeX runs get the cross-reference information correct.

% Sometimes one run after texindex suffices, and sometimes you need more

% than two; texi2dvi does it as many times as necessary.

%

% It is possible to adapt texinfo.tex for other languages, to some

% extent.  You can get the existing language-specific files from the

% full Texinfo distribution.

\message{Loading texinfo [version \texinfoversion]:}

% If in a .fmt file, print the version number

% and turn on active characters that we couldn't do earlier because

% they might have appeared in the input file name.

\everyjob{\message{[Texinfo version \texinfoversion]}%

  \catcode`+=\active \catcode`\_=\active}

\message{Basics,}

\chardef\other=12

% We never want plain's \outer definition of \+ in Texinfo.

% For @tex, we can use \tabalign.

\let\+ = \relax

% Save some plain tex macros whose names we will redefine.

\let\ptexb=\b

\let\ptexbullet=\bullet

\let\ptexc=\c

\let\ptexcomma=\,

\let\ptexdot=\.

\let\ptexdots=\dots

\let\ptexend=\end

\let\ptexequiv=\equiv

\let\ptexexclam=\!

\let\ptexgtr=>

\let\ptexhat=^

\let\ptexi=\i

\let\ptexindent=\indent

\let\ptexlbrace=\{

\let\ptexless=<

\let\ptexplus=+

\let\ptexrbrace=\}

\let\ptexslash=\/

\let\ptexstar=\*

\let\ptext=\t

% If this character appears in an error message or help string, it

% starts a new line in the output.

\newlinechar = `^^J

% Set up fixed words for English if not already set.

\ifx\putwordAppendix\undefined  \gdef\putwordAppendix{Appendix}\fi

\ifx\putwordChapter\undefined   \gdef\putwordChapter{Chapter}\fi

\ifx\putwordfile\undefined      \gdef\putwordfile{file}\fi

\ifx\putwordin\undefined        \gdef\putwordin{in}\fi

\ifx\putwordIndexIsEmpty\undefined     \gdef\putwordIndexIsEmpty{(Index is empty)}\fi

\ifx\putwordIndexNonexistent\undefined \gdef\putwordIndexNonexistent{(Index is nonexistent)}\fi

\ifx\putwordInfo\undefined      \gdef\putwordInfo{Info}\fi

\ifx\putwordInstanceVariableof\undefined \gdef\putwordInstanceVariableof{Instance Variable of}\fi

\ifx\putwordMethodon\undefined  \gdef\putwordMethodon{Method on}\fi

\ifx\putwordNoTitle\undefined   \gdef\putwordNoTitle{No Title}\fi

\ifx\putwordof\undefined        \gdef\putwordof{of}\fi

\ifx\putwordon\undefined        \gdef\putwordon{on}\fi

\ifx\putwordpage\undefined      \gdef\putwordpage{page}\fi

\ifx\putwordsection\undefined   \gdef\putwordsection{section}\fi

\ifx\putwordSection\undefined   \gdef\putwordSection{Section}\fi

\ifx\putwordsee\undefined       \gdef\putwordsee{see}\fi

\ifx\putwordSee\undefined       \gdef\putwordSee{See}\fi

\ifx\putwordShortTOC\undefined  \gdef\putwordShortTOC{Short Contents}\fi

\ifx\putwordTOC\undefined       \gdef\putwordTOC{Table of Contents}\fi

%

\ifx\putwordMJan\undefined \gdef\putwordMJan{January}\fi

\ifx\putwordMFeb\undefined \gdef\putwordMFeb{February}\fi

\ifx\putwordMMar\undefined \gdef\putwordMMar{March}\fi

\ifx\putwordMApr\undefined \gdef\putwordMApr{April}\fi

\ifx\putwordMMay\undefined \gdef\putwordMMay{May}\fi

\ifx\putwordMJun\undefined \gdef\putwordMJun{June}\fi

\ifx\putwordMJul\undefined \gdef\putwordMJul{July}\fi

\ifx\putwordMAug\undefined \gdef\putwordMAug{August}\fi

\ifx\putwordMSep\undefined \gdef\putwordMSep{September}\fi

\ifx\putwordMOct\undefined \gdef\putwordMOct{October}\fi

\ifx\putwordMNov\undefined \gdef\putwordMNov{November}\fi

\ifx\putwordMDec\undefined \gdef\putwordMDec{December}\fi

%

\ifx\putwordDefmac\undefined    \gdef\putwordDefmac{Macro}\fi

\ifx\putwordDefspec\undefined   \gdef\putwordDefspec{Special Form}\fi

\ifx\putwordDefvar\undefined    \gdef\putwordDefvar{Variable}\fi

\ifx\putwordDefopt\undefined    \gdef\putwordDefopt{User Option}\fi

\ifx\putwordDeftypevar\undefined\gdef\putwordDeftypevar{Variable}\fi

\ifx\putwordDeffunc\undefined   \gdef\putwordDeffunc{Function}\fi

\ifx\putwordDeftypefun\undefined\gdef\putwordDeftypefun{Function}\fi

% In some macros, we cannot use the `\? notation---the left quote is

% in some cases the escape char.

\chardef\colonChar = `\:

\chardef\commaChar = `\,

\chardef\dotChar   = `\.

\chardef\equalChar = `\=

\chardef\exclamChar= `\!

\chardef\questChar = `\?

\chardef\semiChar  = `\;

\chardef\spaceChar = `\ %

\chardef\underChar = `\_

% Ignore a token.

%

\def\gobble#1{}

% True if #1 is the empty string, i.e., called like `\ifempty{}'.

%

\def\ifempty#1{\ifemptyx #1\emptymarkA\emptymarkB}%

\def\ifemptyx#1#2\emptymarkB{\ifx #1\emptymarkA}%

% Hyphenation fixes.

\hyphenation{ap-pen-dix}

\hyphenation{eshell}

\hyphenation{mini-buf-fer mini-buf-fers}

\hyphenation{time-stamp}

\hyphenation{white-space}

% Margin to add to right of even pages, to left of odd pages.

\newdimen\bindingoffset

\newdimen\normaloffset

\newdimen\pagewidth \newdimen\pageheight

% Sometimes it is convenient to have everything in the transcript file

% and nothing on the terminal.  We don't just call \tracingall here,

% since that produces some useless output on the terminal.  We also make

% some effort to order the tracing commands to reduce output in the log

% file; cf. trace.sty in LaTeX.

%

\def\gloggingall{\begingroup \globaldefs = 1 \loggingall \endgroup}%

\def\loggingall{%

  \tracingstats2

  \tracingpages1

  \tracinglostchars2  % 2 gives us more in etex

  \tracingparagraphs1

  \tracingoutput1

  \tracingmacros2

  \tracingrestores1

  \showboxbreadth\maxdimen \showboxdepth\maxdimen

  \ifx\eTeXversion\undefined\else % etex gives us more logging

    \tracingscantokens1

    \tracingifs1

    \tracinggroups1

    \tracingnesting2

    \tracingassigns1

  \fi

  \tracingcommands3  % 3 gives us more in etex

  \errorcontextlines\maxdimen

}%

% add check for \lastpenalty to plain's definitions.  If the last thing

% we did was a \nobreak, we don't want to insert more space.

%

\def\smallbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\smallskipamount

  \removelastskip\penalty-50\smallskip\fi\fi}

\def\medbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\medskipamount

  \removelastskip\penalty-100\medskip\fi\fi}

\def\bigbreak{\ifnum\lastpenalty<10000\par\ifdim\lastskip<\bigskipamount

  \removelastskip\penalty-200\bigskip\fi\fi}

% For @cropmarks command.

% Do @cropmarks to get crop marks.

%

\newif\ifcropmarks

\let\cropmarks = \cropmarkstrue

%

% Dimensions to add cropmarks at corners.

% Added by P. A. MacKay, 12 Nov. 1986

%

\newdimen\outerhsize \newdimen\outervsize % set by the paper size routines

\newdimen\cornerlong  \cornerlong=1pc

\newdimen\cornerthick \cornerthick=.3pt

\newdimen\topandbottommargin \topandbottommargin=.75in

% Main output routine.

\chardef\PAGE = 255

\output = {\onepageout{\pagecontents\PAGE}}

\newbox\headlinebox

\newbox\footlinebox

% \onepageout takes a vbox as an argument.  Note that \pagecontents

% does insertions, but you have to call it yourself.

\def\onepageout#1{%

  \ifcropmarks \hoffset=0pt \else \hoffset=\normaloffset \fi

  %

  \ifodd\pageno  \advance\hoffset by \bindingoffset

  \else \advance\hoffset by -\bindingoffset\fi

  %

  % Do this outside of the \shipout so @code etc. will be expanded in

  % the headline as they should be, not taken literally (outputting ''code).

  \setbox\headlinebox = \vbox{\let\hsize=\pagewidth \makeheadline}%

  \setbox\footlinebox = \vbox{\let\hsize=\pagewidth \makefootline}%

  %

  {%

    % Have to do this stuff outside the \shipout because we want it to

    % take effect in \write's, yet the group defined by the \vbox ends

    % before the \shipout runs.

    %

    \escapechar = `\\     % use backslash in output files.

    \indexdummies         % don't expand commands in the output.

    \normalturnoffactive  % \ in index entries must not stay \, e.g., if

                   % the page break happens to be in the middle of an example.

    \shipout\vbox{%

      % Do this early so pdf references go to the beginning of the page.

      \ifpdfmakepagedest \pdfmkdest{\the\pageno} \fi

      %

      \ifcropmarks \vbox to \outervsize\bgroup

        \hsize = \outerhsize

        \vskip-\topandbottommargin

        \vtop to0pt{%

          \line{\ewtop\hfil\ewtop}%

          \nointerlineskip

          \line{%

            \vbox{\moveleft\cornerthick\nstop}%

            \hfill

            \vbox{\moveright\cornerthick\nstop}%

          }%

          \vss}%

        \vskip\topandbottommargin

        \line\bgroup

          \hfil % center the page within the outer (page) hsize.

          \ifodd\pageno\hskip\bindingoffset\fi

          \vbox\bgroup

      \fi

      %

      \unvbox\headlinebox

      \pagebody{#1}%

      \ifdim\ht\footlinebox > 0pt

        % Only leave this space if the footline is nonempty.

        % (We lessened \vsize for it in \oddfootingxxx.)

        % The \baselineskip=24pt in plain's \makefootline has no effect.

        \vskip 2\baselineskip

        \unvbox\footlinebox

      \fi

      %

      \ifcropmarks

          \egroup % end of \vbox\bgroup

        \hfil\egroup % end of (centering) \line\bgroup

        \vskip\topandbottommargin plus1fill minus1fill

        \boxmaxdepth = \cornerthick

        \vbox to0pt{\vss

          \line{%

            \vbox{\moveleft\cornerthick\nsbot}%

            \hfill

            \vbox{\moveright\cornerthick\nsbot}%

          }%

          \nointerlineskip

          \line{\ewbot\hfil\ewbot}%

        }%

      \egroup % \vbox from first cropmarks clause

      \fi

    }% end of \shipout\vbox

  }% end of group with \normalturnoffactive

  \advancepageno

  \ifnum\outputpenalty>-20000 \else\dosupereject\fi

}

\newinsert\margin \dimen\margin=\maxdimen

\def\pagebody#1{\vbox to\pageheight{\boxmaxdepth=\maxdepth #1}}

{\catcode`\@ =11

\gdef\pagecontents#1{\ifvoid\topins\else\unvbox\topins\fi

% marginal hacks, juha@viisa.uucp (Juha Takala)

\ifvoid\margin\else % marginal info is present

  \rlap{\kern\hsize\vbox to\z@{\kern1pt\box\margin \vss}}\fi

\dimen@=\dp#1 \unvbox#1

\ifvoid\footins\else\vskip\skip\footins\footnoterule \unvbox\footins\fi

\ifr@ggedbottom \kern-\dimen@ \vfil \fi}

}

% Here are the rules for the cropmarks.  Note that they are

% offset so that the space between them is truly \outerhsize or \outervsize

% (P. A. MacKay, 12 November, 1986)

%

\def\ewtop{\vrule height\cornerthick depth0pt width\cornerlong}

\def\nstop{\vbox

  {\hrule height\cornerthick depth\cornerlong width\cornerthick}}

\def\ewbot{\vrule height0pt depth\cornerthick width\cornerlong}

\def\nsbot{\vbox

  {\hrule height\cornerlong depth\cornerthick width\cornerthick}}

% Parse an argument, then pass it to #1.  The argument is the rest of

% the input line (except we remove a trailing comment).  #1 should be a

% macro which expects an ordinary undelimited TeX argument.

%

\def\parsearg#1{%

  \let\next = #1%

  \begingroup

    \obeylines

    \futurelet\temp\parseargx

}

% If the next token is an obeyed space (from an @example environment or

% the like), remove it and recurse.  Otherwise, we're done.

\def\parseargx{%

  % \obeyedspace is defined far below, after the definition of \sepspaces.

  \ifx\obeyedspace\temp

    \expandafter\parseargdiscardspace

  \else

    \expandafter\parseargline

  \fi

}

% Remove a single space (as the delimiter token to the macro call).

{\obeyspaces %

 \gdef\parseargdiscardspace {\futurelet\temp\parseargx}}

{\obeylines %

  \gdef\parseargline#1^^M{%

    \endgroup % End of the group started in \parsearg.

    %

    % First remove any @c comment, then any @comment.

    % Result of each macro is put in \toks0.

    \argremovec #1\c\relax %

    \expandafter\argremovecomment \the\toks0 \comment\relax %

    %

    % Call the caller's macro, saved as \next in \parsearg.

    \expandafter\next\expandafter{\the\toks0}%

  }%

}

% Since all \c{,omment} does is throw away the argument, we can let TeX

% do that for us.  The \relax here is matched by the \relax in the call

% in \parseargline; it could be more or less anything, its purpose is

% just to delimit the argument to the \c.

\def\argremovec#1\c#2\relax{\toks0 = {#1}}

\def\argremovecomment#1\comment#2\relax{\toks0 = {#1}}

% \argremovec{,omment} might leave us with trailing spaces, though; e.g.,

%    @end itemize  @c foo

% will have two active spaces as part of the argument with the

% `itemize'.  Here we remove all active spaces from #1, and assign the

% result to \toks0.

%

% This loses if there are any *other* active characters besides spaces

% in the argument -- _ ^ +, for example -- since they get expanded.

% Fortunately, Texinfo does not define any such commands.  (If it ever

% does, the catcode of the characters in questionwill have to be changed

% here.)  But this means we cannot call \removeactivespaces as part of

% \argremovec{,omment}, since @c uses \parsearg, and thus the argument

% that \parsearg gets might well have any character at all in it.

%

\def\removeactivespaces#1{%

  \begingroup

    \ignoreactivespaces

    \edef\temp{#1}%

    \global\toks0 = \expandafter{\temp}%

  \endgroup

}

% Change the active space to expand to nothing.

%

\begingroup

  \obeyspaces

  \gdef\ignoreactivespaces{\obeyspaces\let =\empty}

\endgroup

\def\flushcr{\ifx\par\lisppar \def\next##1{}\else \let\next=\relax \fi \next}

%% These are used to keep @begin/@end levels from running away

%% Call \inENV within environments (after a \begingroup)

\newif\ifENV \ENVfalse \def\inENV{\ifENV\relax\else\ENVtrue\fi}

\def\ENVcheck{%

\ifENV\errmessage{Still within an environment; press RETURN to continue}

\endgroup\fi} % This is not perfect, but it should reduce lossage

% @begin foo  is the same as @foo, for now.

\newhelp\EMsimple{Press RETURN to continue.}

\outer\def\begin{\parsearg\beginxxx}

\def\beginxxx #1{%

\expandafter\ifx\csname #1\endcsname\relax

{\errhelp=\EMsimple \errmessage{Undefined command @begin #1}}\else

\csname #1\endcsname\fi}

% @end foo executes the definition of \Efoo.

%

\def\end{\parsearg\endxxx}

\def\endxxx #1{%

  \removeactivespaces{#1}%

  \edef\endthing{\the\toks0}%

  %

  \expandafter\ifx\csname E\endthing\endcsname\relax

    \expandafter\ifx\csname \endthing\endcsname\relax

      % There's no \foo, i.e., no ``environment'' foo.

      \errhelp = \EMsimple

      \errmessage{Undefined command `@end \endthing'}%

    \else

      \unmatchedenderror\endthing

    \fi

  \else

    % Everything's ok; the right environment has been started.

    \csname E\endthing\endcsname

  \fi

}

% There is an environment #1, but it hasn't been started.  Give an error.

%

\def\unmatchedenderror#1{%

  \errhelp = \EMsimple

  \errmessage{This `@end #1' doesn't have a matching `@#1'}%

}

% Define the control sequence \E#1 to give an unmatched @end error.

%

\def\defineunmatchedend#1{%

  \expandafter\def\csname E#1\endcsname{\unmatchedenderror{#1}}%

}

%% Simple single-character @ commands

% @@ prints an @

% Kludge this until the fonts are right (grr).

\def\@{{\tt\char64}}

% This is turned off because it was never documented

% and you can use @w{...} around a quote to suppress ligatures.

%% Define @` and @' to be the same as ` and '

%% but suppressing ligatures.

%\def\`{{`}}

%\def\'{{'}}

% Used to generate quoted braces.

\def\mylbrace {{\tt\char123}}

\def\myrbrace {{\tt\char125}}

\let\{=\mylbrace

\let\}=\myrbrace

\begingroup

  % Definitions to produce \{ and \} commands for indices,

  % and @{ and @} for the aux file.

  \catcode`\{ = \other \catcode`\} = \other

  \catcode`\[ = 1 \catcode`\] = 2

  \catcode`\! = 0 \catcode`\\ = \other

  !gdef!lbracecmd[\{]%

  !gdef!rbracecmd[\}]%

  !gdef!lbraceatcmd[@{]%

  !gdef!rbraceatcmd[@}]%

!endgroup

% Accents: @, @dotaccent @ringaccent @ubaraccent @udotaccent

% Others are defined by plain TeX: @` @' @" @^ @~ @= @u @v @H.

\let\, = \c

\let\dotaccent = \.

\def\ringaccent#1{{\accent23 #1}}

\let\tieaccent = \t

\let\ubaraccent = \b

\let\udotaccent = \d

% Other special characters: @questiondown @exclamdown

% Plain TeX defines: @AA @AE @O @OE @L (plus lowercase versions) @ss.

\def\questiondown{?`}

\def\exclamdown{!`}

% Dotless i and dotless j, used for accents.

\def\imacro{i}

\def\jmacro{j}

\def\dotless#1{%

  \def\temp{#1}%

  \ifx\temp\imacro \ptexi

  \else\ifx\temp\jmacro \j

  \else \errmessage{@dotless can be used only with i or j}%

  \fi\fi

}

% Be sure we're in horizontal mode when doing a tie, since we make space

% equivalent to this in @example-like environments. Otherwise, a space

% at the beginning of a line will start with \penalty -- and

% since \penalty is valid in vertical mode, we'd end up putting the

% penalty on the vertical list instead of in the new paragraph.

{\catcode`@ = 11

 % Avoid using \@M directly, because that causes trouble

 % if the definition is written into an index file.

 \global\let\tiepenalty = \@M

 \gdef\tie{\leavevmode\penalty\tiepenalty\ }

}

% @: forces normal size whitespace following.

\def\:{\spacefactor=1000 }

% @* forces a line break.

\def\*{\hfil\break\hbox{}\ignorespaces}

% @/ allows a line break.

\let\/=\allowbreak

% @. is an end-of-sentence period.

\def\.{.\spacefactor=3000 }

% @! is an end-of-sentence bang.

\def\!{!\spacefactor=3000 }

% @? is an end-of-sentence query.

\def\?{?\spacefactor=3000 }

% @w prevents a word break.  Without the \leavevmode, @w at the

% beginning of a paragraph, when TeX is still in vertical mode, would

% produce a whole line of output instead of starting the paragraph.

\def\w#1{\leavevmode\hbox{#1}}

% @group ... @end group forces ... to be all on one page, by enclosing

% it in a TeX vbox.  We use \vtop instead of \vbox to construct the box

% to keep its height that of a normal line.  According to the rules for

% \topskip (p.114 of the TeXbook), the glue inserted is

% max (\topskip - \ht (first item), 0).  If that height is large,

% therefore, no glue is inserted, and the space between the headline and

% the text is small, which looks bad.

%

% Another complication is that the group might be very large.  This can

% cause the glue on the previous page to be unduly stretched, because it

% does not have much material.  In this case, it's better to add an

% explicit \vfill so that the extra space is at the bottom.  The

% threshold for doing this is if the group is more than \vfilllimit

% percent of a page (\vfilllimit can be changed inside of @tex).

%

\newbox\groupbox

\def\vfilllimit{0.7}

%

\def\group{\begingroup

  \ifnum\catcode13=\active \else

    \errhelp = \groupinvalidhelp

    \errmessage{@group invalid in context where filling is enabled}%

  \fi

  %

  % The \vtop we start below produces a box with normal height and large

  % depth; thus, TeX puts \baselineskip glue before it, and (when the

  % next line of text is done) \lineskip glue after it.  (See p.82 of

  % the TeXbook.)  Thus, space below is not quite equal to space

  % above.  But it's pretty close.

  \def\Egroup{%

    \egroup           % End the \vtop.

    % \dimen0 is the vertical size of the group's box.

    \dimen0 = \ht\groupbox  \advance\dimen0 by \dp\groupbox

    % \dimen2 is how much space is left on the page (more or less).

    \dimen2 = \pageheight   \advance\dimen2 by -\pagetotal

    % if the group doesn't fit on the current page, and it's a big big

    % group, force a page break.

    \ifdim \dimen0 > \dimen2

      \ifdim \pagetotal < \vfilllimit\pageheight

        \page

      \fi

    \fi

    \copy\groupbox

    \endgroup         % End the \group.

  }%

  %

  \setbox\groupbox = \vtop\bgroup

    % We have to put a strut on the last line in case the @group is in

    % the midst of an example, rather than completely enclosing it.

    % Otherwise, the interline space between the last line of the group

    % and the first line afterwards is too small.  But we can't put the

    % strut in \Egroup, since there it would be on a line by itself.

    % Hence this just inserts a strut at the beginning of each line.

    \everypar = {\strut}%

    %

    % Since we have a strut on every line, we don't need any of TeX's

    % normal interline spacing.

    \offinterlineskip

    %

    % OK, but now we have to do something about blank

    % lines in the input in @example-like environments, which normally

    % just turn into \lisppar, which will insert no space now that we've

    % turned off the interline space.  Simplest is to make them be an

    % empty paragraph.

    \ifx\par\lisppar

      \edef\par{\leavevmode \par}%

      %

      % Reset ^^M's definition to new definition of \par.

      \obeylines

    \fi

    %

    % Do @comment since we are called inside an environment such as

    % @example, where each end-of-line in the input causes an

    % end-of-line in the output.  We don't want the end-of-line after

    % the `@group' to put extra space in the output.  Since @group

    % should appear on a line by itself (according to the Texinfo

    % manual), we don't worry about eating any user text.

    \comment

}

%

% TeX puts in an \escapechar (i.e., `@') at the beginning of the help

% message, so this ends up printing `@group can only ...'.

%

\newhelp\groupinvalidhelp{%

group can only be used in environments such as @example,^^J%

where each line of input produces a line of output.}

% @need space-in-mils

% forces a page break if there is not space-in-mils remaining.

\newdimen\mil  \mil=0.001in

\def\need{\parsearg\needx}

% Old definition--didn't work.

%\def\needx #1{\par %

%% This method tries to make TeX break the page naturally

%% if the depth of the box does not fit.

%{\baselineskip=0pt%

%\vtop to #1\mil{\vfil}\kern -#1\mil\nobreak

%\prevdepth=-1000pt

%}}

\def\needx#1{%

  % Ensure vertical mode, so we don't make a big box in the middle of a

  % paragraph.

  \par

  %

  % If the @need value is less than one line space, it's useless.

  \dimen0 = #1\mil

  \dimen2 = \ht\strutbox

  \advance\dimen2 by \dp\strutbox

  \ifdim\dimen0 > \dimen2

    %

    % Do a \strut just to make the height of this box be normal, so the

    % normal leading is inserted relative to the preceding line.

    % And a page break here is fine.

    \vtop to #1\mil{\strut\vfil}%

    %

    % TeX does not even consider page breaks if a penalty added to the

    % main vertical list is 10000 or more.  But in order to see if the

    % empty box we just added fits on the page, we must make it consider

    % page breaks.  On the other hand, we don't want to actually break the

    % page after the empty box.  So we use a penalty of 9999.

    %

    % There is an extremely small chance that TeX will actually break the

    % page at this \penalty, if there are no other feasible breakpoints in

    % sight.  (If the user is using lots of big @group commands, which

    % almost-but-not-quite fill up a page, TeX will have a hard time doing

    % good page breaking, for example.)  However, I could not construct an

    % example where a page broke at this \penalty; if it happens in a real

    % document, then we can reconsider our strategy.

    \penalty9999

    %

    % Back up by the size of the box, whether we did a page break or not.

    \kern -#1\mil

    %

    % Do not allow a page break right after this kern.

    \nobreak

  \fi

}

% @br   forces paragraph break

\let\br = \par

% @dots{} output an ellipsis using the current font.

% We do .5em per period so that it has the same spacing in a typewriter

% font as three actual period characters.

%

\def\dots{%

  \leavevmode

  \hbox to 1.5em{%

    \hskip 0pt plus 0.25fil minus 0.25fil

    .\hss.\hss.%

    \hskip 0pt plus 0.5fil minus 0.5fil

  }%

}

% @enddots{} is an end-of-sentence ellipsis.

%

\def\enddots{%

  \leavevmode

  \hbox to 2em{%

    \hskip 0pt plus 0.25fil minus 0.25fil

    .\hss.\hss.\hss.%

    \hskip 0pt plus 0.5fil minus 0.5fil

  }%

  \spacefactor=3000

}

% @page forces the start of a new page.

%

\def\page{\par\vfill\supereject}

% @exdent text....

% outputs text on separate line in roman font, starting at standard page margin

% This records the amount of indent in the innermost environment.

% That's how much \exdent should take out.

\newskip\exdentamount

% This defn is used inside fill environments such as @defun.

\def\exdent{\parsearg\exdentyyy}

\def\exdentyyy #1{{\hfil\break\hbox{\kern -\exdentamount{\rm#1}}\hfil\break}}

% This defn is used inside nofill environments such as @example.

\def\nofillexdent{\parsearg\nofillexdentyyy}

\def\nofillexdentyyy #1{{\advance \leftskip by -\exdentamount

\leftline{\hskip\leftskip{\rm#1}}}}

% @inmargin{WHICH}{TEXT} puts TEXT in the WHICH margin next to the current

% paragraph.  For more general purposes, use the \margin insertion

% class.  WHICH is `l' or `r'.

%

\newskip\inmarginspacing \inmarginspacing=1cm

\def\strutdepth{\dp\strutbox}

%

\def\doinmargin#1#2{\strut\vadjust{%

  \nobreak

  \kern-\strutdepth

  \vtop to \strutdepth{%

    \baselineskip=\strutdepth

    \vss

    % if you have multiple lines of stuff to put here, you'll need to

    % make the vbox yourself of the appropriate size.

    \ifx#1l%

      \llap{\ignorespaces #2\hskip\inmarginspacing}%

    \else

      \rlap{\hskip\hsize \hskip\inmarginspacing \ignorespaces #2}%

    \fi

    \null

  }%

}}

\def\inleftmargin{\doinmargin l}

\def\inrightmargin{\doinmargin r}

%

% @inmargin{TEXT [, RIGHT-TEXT]}

% (if RIGHT-TEXT is given, use TEXT for left page, RIGHT-TEXT for right;

% else use TEXT for both).

%

\def\inmargin#1{\parseinmargin #1,,\finish}

\def\parseinmargin#1,#2,#3\finish{% not perfect, but better than nothing.

  \setbox0 = \hbox{\ignorespaces #2}%

  \ifdim\wd0 > 0pt

    \def\lefttext{#1}%  have both texts

    \def\righttext{#2}%

  \else

    \def\lefttext{#1}%  have only one text

    \def\righttext{#1}%

  \fi

  %

  \ifodd\pageno

    \def\temp{\inrightmargin\righttext}% odd page -> outside is right margin

  \else

    \def\temp{\inleftmargin\lefttext}%

  \fi

  \temp

}

% @include file    insert text of that file as input.

% Allow normal characters that  we make active in the argument (a file name).

\def\include{\begingroup

  \catcode`\\=\other

  \catcode`~=\other

  \catcode`^=\other

  \catcode`_=\other

  \catcode`|=\other

  \catcode`<=\other

  \catcode`>=\other

  \catcode`+=\other

  \parsearg\includezzz}

% Restore active chars for included file.

\def\includezzz#1{\endgroup\begingroup

  % Read the included file in a group so nested @include's work.

  \def\thisfile{#1}%

  \let\value=\expandablevalue

  \input\thisfile

\endgroup}

\def\thisfile{}

% @center line

% outputs that line, centered.

%

\def\center{\parsearg\docenter}

\def\docenter#1{{%

  \ifhmode \hfil\break \fi

  \advance\hsize by -\leftskip

  \advance\hsize by -\rightskip

  \line{\hfil \ignorespaces#1\unskip \hfil}%

  \ifhmode \break \fi

}}

% @sp n   outputs n lines of vertical space

\def\sp{\parsearg\spxxx}

\def\spxxx #1{\vskip #1\baselineskip}

% @comment ...line which is ignored...

% @c is the same as @comment

% @ignore ... @end ignore  is another way to write a comment

\def\comment{\begingroup \catcode`\^^M=\other%

\catcode`\@=\other \catcode`\{=\other \catcode`\}=\other%

\commentxxx}

{\catcode`\^^M=\other \gdef\commentxxx#1^^M{\endgroup}}

\let\c=\comment

% @paragraphindent NCHARS

% We'll use ems for NCHARS, close enough.

% NCHARS can also be the word `asis' or `none'.

% We cannot feasibly implement @paragraphindent asis, though.

%

\def\asisword{asis} % no translation, these are keywords

\def\noneword{none}

%

\def\paragraphindent{\parsearg\doparagraphindent}

\def\doparagraphindent#1{%

  \def\temp{#1}%

  \ifx\temp\asisword

  \else

    \ifx\temp\noneword

      \defaultparindent = 0pt

    \else

      \defaultparindent = #1em

    \fi

  \fi

  \parindent = \defaultparindent

}

% @exampleindent NCHARS

% We'll use ems for NCHARS like @paragraphindent.

% It seems @exampleindent asis isn't necessary, but

% I preserve it to make it similar to @paragraphindent.

\def\exampleindent{\parsearg\doexampleindent}

\def\doexampleindent#1{%

  \def\temp{#1}%

  \ifx\temp\asisword

  \else

    \ifx\temp\noneword

      \lispnarrowing = 0pt

    \else

      \lispnarrowing = #1em

    \fi

  \fi

}

% @firstparagraphindent WORD

% If WORD is `none', then suppress indentation of the first paragraph

% after a section heading.  If WORD is `insert', then do indent at such

% paragraphs.

%

% The paragraph indentation is suppressed or not by calling

% \suppressfirstparagraphindent, which the sectioning commands do.

% We switch the definition of this back and forth according to WORD.

% By default, we suppress indentation.

%

\def\suppressfirstparagraphindent{\dosuppressfirstparagraphindent}

\newdimen\currentparindent

%

\def\insertword{insert}

%

\def\firstparagraphindent{\parsearg\dofirstparagraphindent}

\def\dofirstparagraphindent#1{%

  \def\temp{#1}%

  \ifx\temp\noneword

    \let\suppressfirstparagraphindent = \dosuppressfirstparagraphindent

  \else\ifx\temp\insertword

    \let\suppressfirstparagraphindent = \relax

  \else

    \errhelp = \EMsimple

    \errmessage{Unknown @firstparagraphindent option `\temp'}%

  \fi\fi

}

% Here is how we actually suppress indentation.  Redefine \everypar to

% \kern backwards by \parindent, and then reset itself to empty.

%

% We also make \indent itself not actually do anything until the next

% paragraph.

%

\gdef\dosuppressfirstparagraphindent{%

  \gdef\indent{%

    \global\let\indent=\ptexindent

    \global\everypar = {}%

  }%

  \global\everypar = {%

    \kern-\parindent

    \global\let\indent=\ptexindent

    \global\everypar = {}%

  }%

}%

% @asis just yields its argument.  Used with @table, for example.

%

\def\asis#1{#1}

% @math outputs its argument in math mode.

% We don't use $'s directly in the definition of \math because we need

% to set catcodes according to plain TeX first, to allow for subscripts,

% superscripts, special math chars, etc.

%

\let\implicitmath = $%$ font-lock fix

%

% One complication: _ usually means subscripts, but it could also mean

% an actual _ character, as in @math{@var{some_variable} + 1}.  So make

% _ within @math be active (mathcode "8000), and distinguish by seeing

% if the current family is \slfam, which is what @var uses.

%

{\catcode\underChar = \active

\gdef\mathunderscore{%

  \catcode\underChar=\active

  \def_{\ifnum\fam=\slfam \_\else\sb\fi}%

}}

%

% Another complication: we want \\ (and @\) to output a \ character.

% FYI, plain.tex uses \\ as a temporary control sequence (why?), but

% this is not advertised and we don't care.  Texinfo does not

% otherwise define @\.

%

% The \mathchar is class=0=ordinary, family=7=ttfam, position=5C=\.

\def\mathbackslash{\ifnum\fam=\ttfam \mathchar"075C \else\backslash \fi}

%

\def\math{%

  \tex

  \mathcode`\_="8000 \mathunderscore

  \let\\ = \mathbackslash

  \mathactive

  \implicitmath\finishmath}

\def\finishmath#1{#1\implicitmath\Etex}

% Some active characters (such as <) are spaced differently in math.

% We have to reset their definitions in case the @math was an

% argument to a command which set the catcodes (such as @item or @section).

%

{

  \catcode`^ = \active

  \catcode`< = \active

  \catcode`> = \active

  \catcode`+ = \active

  \gdef\mathactive{%

    \let^ = \ptexhat

    \let< = \ptexless

    \let> = \ptexgtr

    \let+ = \ptexplus

  }

}

% @bullet and @minus need the same treatment as @math, just above.

\def\bullet{\implicitmath\ptexbullet\implicitmath}

\def\minus{\implicitmath-\implicitmath}

% @refill is a no-op.