% 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.

 \let\refill=\relax

 % If working on a large document in chapters, it is convenient to

 % be able to disable indexing, cross-referencing, and contents, for test runs.

 % This is done with @novalidate (before @setfilename).

 %

 \newif\iflinks \linkstrue % by default we want the aux files.

 \let\novalidate = \linksfalse

 % @setfilename is done at the beginning of every texinfo file.

 % So open here the files we need to have open while reading the input.

 % This makes it possible to make a .fmt file for texinfo.

 \def\setfilename{%

    \iflinks

      \readauxfile

    \fi % \openindices needs to do some work in any case.

    \openindices

    \fixbackslash  % Turn off hack to swallow `\input texinfo'.

    \global\let\setfilename=\comment % Ignore extra @setfilename cmds.

    %

    % If texinfo.cnf is present on the system, read it.

    % Useful for site-wide @afourpaper, etc.

    % Just to be on the safe side, close the input stream before the \input.

    \openin 1 texinfo.cnf

    \ifeof1 \let\temp=\relax \else \def\temp{\input texinfo.cnf }\fi

    \closein1

    \temp

    %

    \comment % Ignore the actual filename.

 }

 % Called from \setfilename.

 %

 \def\openindices{%

   \newindex{cp}%

   \newcodeindex{fn}%

   \newcodeindex{vr}%

   \newcodeindex{tp}%

   \newcodeindex{ky}%

   \newcodeindex{pg}%

 }

 % @bye.

 \outer\def\bye{\pagealignmacro\tracingstats=1\ptexend}

 \message{pdf,}

 % adobe `portable' document format

 \newcount\tempnum

 \newcount\lnkcount

 \newtoks\filename

 \newcount\filenamelength

 \newcount\pgn

 \newtoks\toksA

 \newtoks\toksB

 \newtoks\toksC

 \newtoks\toksD

 \newbox\boxA

 \newcount\countA

 \newif\ifpdf

 \newif\ifpdfmakepagedest

 \ifx\pdfoutput\undefined

   \pdffalse

   \let\pdfmkdest = \gobble

   \let\pdfurl = \gobble

   \let\endlink = \relax

   \let\linkcolor = \relax

   \let\pdfmakeoutlines = \relax

 \else

   \pdftrue

   \pdfoutput = 1

   \input pdfcolor

   \def\dopdfimage#1#2#3{%

     \def\imagewidth{#2}%

     \def\imageheight{#3}%

     % without \immediate, pdftex seg faults when the same image is

     % included twice.  (Version 3.14159-pre-1.0-unofficial-20010704.)

     \ifnum\pdftexversion < 14

       \immediate\pdfimage

     \else

       \immediate\pdfximage

     \fi

       \ifx\empty\imagewidth\else width \imagewidth \fi

       \ifx\empty\imageheight\else height \imageheight \fi

       \ifnum\pdftexversion<13

          #1.pdf%

        \else

          {#1.pdf}%

        \fi

     \ifnum\pdftexversion < 14 \else

       \pdfrefximage \pdflastximage

     \fi}

   \def\pdfmkdest#1{{\normalturnoffactive \pdfdest name{#1} xyz}}

   \def\pdfmkpgn#1{#1}

   \let\linkcolor = \Blue  % was Cyan, but that seems light?

   \def\endlink{\Black\pdfendlink}

   % Adding outlines to PDF; macros for calculating structure of outlines

   % come from Petr Olsak

   \def\expnumber#1{\expandafter\ifx\csname#1\endcsname\relax 0%

     \else \csname#1\endcsname \fi}

   \def\advancenumber#1{\tempnum=\expnumber{#1}\relax

     \advance\tempnum by1

     \expandafter\xdef\csname#1\endcsname{\the\tempnum}}

   \def\pdfmakeoutlines{{%

     \openin 1 \jobname.toc

     \ifeof 1\else\begingroup

       \closein 1

       % Thanh's hack / proper braces in bookmarks

       \edef\mylbrace{\iftrue \string{\else}\fi}\let\{=\mylbrace

       \edef\myrbrace{\iffalse{\else\string}\fi}\let\}=\myrbrace

       %

       \def\chapentry ##1##2##3{}

       \def\secentry ##1##2##3##4{\advancenumber{chap##2}}

       \def\subsecentry ##1##2##3##4##5{\advancenumber{sec##2.##3}}

       \def\subsubsecentry ##1##2##3##4##5##6{\advancenumber{subsec##2.##3.##4}}

       \let\appendixentry = \chapentry

       \let\unnumbchapentry = \chapentry

       \let\unnumbsecentry = \secentry

       \let\unnumbsubsecentry = \subsecentry

       \let\unnumbsubsubsecentry = \subsubsecentry

       \input \jobname.toc

       \def\chapentry ##1##2##3{%

         \pdfoutline goto name{\pdfmkpgn{##3}}count-\expnumber{chap##2}{##1}}

       \def\secentry ##1##2##3##4{%

         \pdfoutline goto name{\pdfmkpgn{##4}}count-\expnumber{sec##2.##3}{##1}}

       \def\subsecentry ##1##2##3##4##5{%

         \pdfoutline goto name{\pdfmkpgn{##5}}count-\expnumber{subsec##2.##3.##4}{##1}}

       \def\subsubsecentry ##1##2##3##4##5##6{%

         \pdfoutline goto name{\pdfmkpgn{##6}}{##1}}

       \let\appendixentry = \chapentry

       \let\unnumbchapentry = \chapentry

       \let\unnumbsecentry = \secentry

       \let\unnumbsubsecentry = \subsecentry

       \let\unnumbsubsubsecentry = \subsubsecentry

       %

       % Make special characters normal for writing to the pdf file.

       %

       \indexnofonts

       \let\tt=\relax

       \turnoffactive

       \input \jobname.toc

     \endgroup\fi

   }}

   \def\makelinks #1,{%

     \def\params{#1}\def\E{END}%

     \ifx\params\E

       \let\nextmakelinks=\relax

     \else

       \let\nextmakelinks=\makelinks

       \ifnum\lnkcount>0,\fi

       \picknum{#1}%

       \startlink attr{/Border [0 0 0]}

         goto name{\pdfmkpgn{\the\pgn}}%

       \linkcolor #1%

       \advance\lnkcount by 1%

       \endlink

     \fi

     \nextmakelinks

   }

   \def\picknum#1{\expandafter\pn#1}

   \def\pn#1{%

     \def\p{#1}%

     \ifx\p\lbrace

       \let\nextpn=\ppn

     \else

       \let\nextpn=\ppnn

       \def\first{#1}

     \fi

     \nextpn

   }

   \def\ppn#1{\pgn=#1\gobble}

   \def\ppnn{\pgn=\first}

   \def\pdfmklnk#1{\lnkcount=0\makelinks #1,END,}

   \def\addtokens#1#2{\edef\addtoks{\noexpand#1={\the#1#2}}\addtoks}

   \def\skipspaces#1{\def\PP{#1}\def\D{|}%

     \ifx\PP\D\let\nextsp\relax

     \else\let\nextsp\skipspaces

       \ifx\p\space\else\addtokens{\filename}{\PP}%

         \advance\filenamelength by 1

       \fi

     \fi

     \nextsp}

   \def\getfilename#1{\filenamelength=0\expandafter\skipspaces#1|\relax}

   \ifnum\pdftexversion < 14

     \let \startlink \pdfannotlink

   \else

     \let \startlink \pdfstartlink

   \fi

   \def\pdfurl#1{%

     \begingroup

       \normalturnoffactive\def\@{@}%

       \let\value=\expandablevalue

       \leavevmode\Red

       \startlink attr{/Border [0 0 0]}%

         user{/Subtype /Link /A << /S /URI /URI (#1) >>}%

         % #1

     \endgroup}

   \def\pdfgettoks#1.{\setbox\boxA=\hbox{\toksA={#1.}\toksB={}\maketoks}}

   \def\addtokens#1#2{\edef\addtoks{\noexpand#1={\the#1#2}}\addtoks}

   \def\adn#1{\addtokens{\toksC}{#1}\global\countA=1\let\next=\maketoks}

   \def\poptoks#1#2|ENDTOKS|{\let\first=#1\toksD={#1}\toksA={#2}}

   \def\maketoks{%

     \expandafter\poptoks\the\toksA|ENDTOKS|

     \ifx\first0\adn0

     \else\ifx\first1\adn1 \else\ifx\first2\adn2 \else\ifx\first3\adn3

     \else\ifx\first4\adn4 \else\ifx\first5\adn5 \else\ifx\first6\adn6

     \else\ifx\first7\adn7 \else\ifx\first8\adn8 \else\ifx\first9\adn9

     \else

       \ifnum0=\countA\else\makelink\fi

       \ifx\first.\let\next=\done\else

         \let\next=\maketoks

         \addtokens{\toksB}{\the\toksD}

         \ifx\first,\addtokens{\toksB}{\space}\fi

       \fi

     \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi

     \next}

   \def\makelink{\addtokens{\toksB}%

     {\noexpand\pdflink{\the\toksC}}\toksC={}\global\countA=0}

   \def\pdflink#1{%

     \startlink attr{/Border [0 0 0]} goto name{\pdfmkpgn{#1}}

     \linkcolor #1\endlink}

   \def\done{\edef\st{\global\noexpand\toksA={\the\toksB}}\st}

 \fi % \ifx\pdfoutput

 \message{fonts,}

 % Font-change commands.

 % Texinfo sort of supports the sans serif font style, which plain TeX does not.

 % So we set up a \sf analogous to plain's \rm, etc.

 \newfam\sffam

 \def\sf{\fam=\sffam \tensf}

 \let\li = \sf % Sometimes we call it \li, not \sf.

 % We don't need math for this one.

 \def\ttsl{\tenttsl}

 % Default leading.

 \newdimen\textleading  \textleading = 13.2pt

 % Set the baselineskip to #1, and the lineskip and strut size

 % correspondingly.  There is no deep meaning behind these magic numbers

 % used as factors; they just match (closely enough) what Knuth defined.

 %

 \def\lineskipfactor{.08333}

 \def\strutheightpercent{.70833}

 \def\strutdepthpercent {.29167}

 %

 \def\setleading#1{%

   \normalbaselineskip = #1\relax

   \normallineskip = \lineskipfactor\normalbaselineskip

   \normalbaselines

   \setbox\strutbox =\hbox{%

     \vrule width0pt height\strutheightpercent\baselineskip

                     depth \strutdepthpercent \baselineskip

   }%

 }

 % Set the font macro #1 to the font named #2, adding on the

 % specified font prefix (normally `cm').

 % #3 is the font's design size, #4 is a scale factor

 \def\setfont#1#2#3#4{\font#1=\fontprefix#2#3 scaled #4}

 % Use cm as the default font prefix.

 % To specify the font prefix, you must define \fontprefix

 % before you read in texinfo.tex.

 \ifx\fontprefix\undefined

 \def\fontprefix{cm}

 \fi

 % Support font families that don't use the same naming scheme as CM.

 \def\rmshape{r}

 \def\rmbshape{bx}               %where the normal face is bold

 \def\bfshape{b}

 \def\bxshape{bx}

 \def\ttshape{tt}

 \def\ttbshape{tt}

 \def\ttslshape{sltt}

 \def\itshape{ti}

 \def\itbshape{bxti}

 \def\slshape{sl}

 \def\slbshape{bxsl}

 \def\sfshape{ss}

 \def\sfbshape{ss}

 \def\scshape{csc}

 \def\scbshape{csc}

 \newcount\mainmagstep

 \ifx\bigger\relax

   % not really supported.

   \mainmagstep=\magstep1

   \setfont\textrm\rmshape{12}{1000}

   \setfont\texttt\ttshape{12}{1000}

 \else

   \mainmagstep=\magstephalf

   \setfont\textrm\rmshape{10}{\mainmagstep}

   \setfont\texttt\ttshape{10}{\mainmagstep}

 \fi

 % Instead of cmb10, you may want to use cmbx10.

 % cmbx10 is a prettier font on its own, but cmb10

 % looks better when embedded in a line with cmr10

 % (in Bob's opinion).

 \setfont\textbf\bfshape{10}{\mainmagstep}

 \setfont\textit\itshape{10}{\mainmagstep}

 \setfont\textsl\slshape{10}{\mainmagstep}

 \setfont\textsf\sfshape{10}{\mainmagstep}

 \setfont\textsc\scshape{10}{\mainmagstep}

 \setfont\textttsl\ttslshape{10}{\mainmagstep}

 \font\texti=cmmi10 scaled \mainmagstep

 \font\textsy=cmsy10 scaled \mainmagstep

 % A few fonts for @defun, etc.

 \setfont\defbf\bxshape{10}{\magstep1} %was 1314

 \setfont\deftt\ttshape{10}{\magstep1}

 \def\df{\let\tentt=\deftt \let\tenbf = \defbf \bf}

 % Fonts for indices, footnotes, small examples (9pt).

 \setfont\smallrm\rmshape{9}{1000}

 \setfont\smalltt\ttshape{9}{1000}

 \setfont\smallbf\bfshape{10}{900}

 \setfont\smallit\itshape{9}{1000}

 \setfont\smallsl\slshape{9}{1000}

 \setfont\smallsf\sfshape{9}{1000}

 \setfont\smallsc\scshape{10}{900}

 \setfont\smallttsl\ttslshape{10}{900}

 \font\smalli=cmmi9

 \font\smallsy=cmsy9

 % Fonts for small examples (8pt).

 \setfont\smallerrm\rmshape{8}{1000}

 \setfont\smallertt\ttshape{8}{1000}

 \setfont\smallerbf\bfshape{10}{800}

 \setfont\smallerit\itshape{8}{1000}

 \setfont\smallersl\slshape{8}{1000}

 \setfont\smallersf\sfshape{8}{1000}

 \setfont\smallersc\scshape{10}{800}

 \setfont\smallerttsl\ttslshape{10}{800}

 \font\smalleri=cmmi8

 \font\smallersy=cmsy8

 % Fonts for title page:

 \setfont\titlerm\rmbshape{12}{\magstep3}

 \setfont\titleit\itbshape{10}{\magstep4}

 \setfont\titlesl\slbshape{10}{\magstep4}

 \setfont\titlett\ttbshape{12}{\magstep3}

 \setfont\titlettsl\ttslshape{10}{\magstep4}

 \setfont\titlesf\sfbshape{17}{\magstep1}

 \let\titlebf=\titlerm

 \setfont\titlesc\scbshape{10}{\magstep4}

 \font\titlei=cmmi12 scaled \magstep3

 \font\titlesy=cmsy10 scaled \magstep4

 \def\authorrm{\secrm}

 \def\authortt{\sectt}

 % Chapter (and unnumbered) fonts (17.28pt).

 \setfont\chaprm\rmbshape{12}{\magstep2}

 \setfont\chapit\itbshape{10}{\magstep3}

 \setfont\chapsl\slbshape{10}{\magstep3}

 \setfont\chaptt\ttbshape{12}{\magstep2}

 \setfont\chapttsl\ttslshape{10}{\magstep3}

 \setfont\chapsf\sfbshape{17}{1000}

 \let\chapbf=\chaprm

 \setfont\chapsc\scbshape{10}{\magstep3}

 \font\chapi=cmmi12 scaled \magstep2

 \font\chapsy=cmsy10 scaled \magstep3

 % Section fonts (14.4pt).

 \setfont\secrm\rmbshape{12}{\magstep1}

 \setfont\secit\itbshape{10}{\magstep2}

 \setfont\secsl\slbshape{10}{\magstep2}

 \setfont\sectt\ttbshape{12}{\magstep1}

 \setfont\secttsl\ttslshape{10}{\magstep2}

 \setfont\secsf\sfbshape{12}{\magstep1}

 \let\secbf\secrm

 \setfont\secsc\scbshape{10}{\magstep2}

 \font\seci=cmmi12 scaled \magstep1

 \font\secsy=cmsy10 scaled \magstep2

 % Subsection fonts (13.15pt).

 \setfont\ssecrm\rmbshape{12}{\magstephalf}

 \setfont\ssecit\itbshape{10}{1315}

 \setfont\ssecsl\slbshape{10}{1315}

 \setfont\ssectt\ttbshape{12}{\magstephalf}

 \setfont\ssecttsl\ttslshape{10}{1315}

 \setfont\ssecsf\sfbshape{12}{\magstephalf}

 \let\ssecbf\ssecrm

 \setfont\ssecsc\scbshape{10}{\magstep1}

 \font\sseci=cmmi12 scaled \magstephalf

 \font\ssecsy=cmsy10 scaled 1315

 % The smallcaps and symbol fonts should actually be scaled \magstep1.5,

 % but that is not a standard magnification.

 % In order for the font changes to affect most math symbols and letters,

 % we have to define the \textfont of the standard families.  Since

 % texinfo doesn't allow for producing subscripts and superscripts except

 % in the main text, we don't bother to reset \scriptfont and

 % \scriptscriptfont (which would also require loading a lot more fonts).

 %

 \def\resetmathfonts{%

   \textfont0=\tenrm \textfont1=\teni \textfont2=\tensy

   \textfont\itfam=\tenit \textfont\slfam=\tensl \textfont\bffam=\tenbf

   \textfont\ttfam=\tentt \textfont\sffam=\tensf

 }

 % The font-changing commands redefine the meanings of \tenSTYLE, instead

 % of just \STYLE.  We do this so that font changes will continue to work

 % in math mode, where it is the current \fam that is relevant in most

 % cases, not the current font.  Plain TeX does \def\bf{\fam=\bffam

 % \tenbf}, for example.  By redefining \tenbf, we obviate the need to

 % redefine \bf itself.

 \def\textfonts{%

   \let\tenrm=\textrm \let\tenit=\textit \let\tensl=\textsl

   \let\tenbf=\textbf \let\tentt=\texttt \let\smallcaps=\textsc

   \let\tensf=\textsf \let\teni=\texti \let\tensy=\textsy \let\tenttsl=\textttsl

   \resetmathfonts \setleading{\textleading}}

 \def\titlefonts{%

   \let\tenrm=\titlerm \let\tenit=\titleit \let\tensl=\titlesl

   \let\tenbf=\titlebf \let\tentt=\titlett \let\smallcaps=\titlesc

   \let\tensf=\titlesf \let\teni=\titlei \let\tensy=\titlesy

   \let\tenttsl=\titlettsl

   \resetmathfonts \setleading{25pt}}

 \def\titlefont#1{{\titlefonts\rm #1}}

 \def\chapfonts{%

   \let\tenrm=\chaprm \let\tenit=\chapit \let\tensl=\chapsl

   \let\tenbf=\chapbf \let\tentt=\chaptt \let\smallcaps=\chapsc

   \let\tensf=\chapsf \let\teni=\chapi \let\tensy=\chapsy \let\tenttsl=\chapttsl

   \resetmathfonts \setleading{19pt}}

 \def\secfonts{%

   \let\tenrm=\secrm \let\tenit=\secit \let\tensl=\secsl

   \let\tenbf=\secbf \let\tentt=\sectt \let\smallcaps=\secsc

   \let\tensf=\secsf \let\teni=\seci \let\tensy=\secsy \let\tenttsl=\secttsl

   \resetmathfonts \setleading{16pt}}

 \def\subsecfonts{%

   \let\tenrm=\ssecrm \let\tenit=\ssecit \let\tensl=\ssecsl

   \let\tenbf=\ssecbf \let\tentt=\ssectt \let\smallcaps=\ssecsc

   \let\tensf=\ssecsf \let\teni=\sseci \let\tensy=\ssecsy \let\tenttsl=\ssecttsl

   \resetmathfonts \setleading{15pt}}

 \let\subsubsecfonts = \subsecfonts % Maybe make sssec fonts scaled magstephalf?

 \def\smallfonts{%

   \let\tenrm=\smallrm \let\tenit=\smallit \let\tensl=\smallsl

   \let\tenbf=\smallbf \let\tentt=\smalltt \let\smallcaps=\smallsc

   \let\tensf=\smallsf \let\teni=\smalli \let\tensy=\smallsy

   \let\tenttsl=\smallttsl

   \resetmathfonts \setleading{10.5pt}}

 \def\smallerfonts{%

   \let\tenrm=\smallerrm \let\tenit=\smallerit \let\tensl=\smallersl

   \let\tenbf=\smallerbf \let\tentt=\smallertt \let\smallcaps=\smallersc

   \let\tensf=\smallersf \let\teni=\smalleri \let\tensy=\smallersy

   \let\tenttsl=\smallerttsl

   \resetmathfonts \setleading{9.5pt}}

 % Set the fonts to use with the @small... environments.

 \let\smallexamplefonts = \smallfonts

 % About \smallexamplefonts.  If we use \smallfonts (9pt), @smallexample

 % can fit this many characters:

 %   8.5x11=86   smallbook=72  a4=90  a5=69

 % If we use \smallerfonts (8pt), then we can fit this many characters:

 %   8.5x11=90+  smallbook=80  a4=90+  a5=77

 % For me, subjectively, the few extra characters that fit aren't worth

 % the additional smallness of 8pt.  So I'm making the default 9pt.

 %

 % By the way, for comparison, here's what fits with @example (10pt):

 %   8.5x11=71  smallbook=60  a4=75  a5=58

 %

 % I wish we used A4 paper on this side of the Atlantic.

 %

 % --karl, 24jan03.

 % Set up the default fonts, so we can use them for creating boxes.

 %

 \textfonts

 % Define these so they can be easily changed for other fonts.

 \def\angleleft{$\langle$}

 \def\angleright{$\rangle$}

 % Count depth in font-changes, for error checks

 \newcount\fontdepth \fontdepth=0

 % Fonts for short table of contents.

 \setfont\shortcontrm\rmshape{12}{1000}

 \setfont\shortcontbf\bxshape{12}{1000}

 \setfont\shortcontsl\slshape{12}{1000}

 \setfont\shortconttt\ttshape{12}{1000}

 %% Add scribe-like font environments, plus @l for inline lisp (usually sans

 %% serif) and @ii for TeX italic

 % \smartitalic{ARG} outputs arg in italics, followed by an italic correction

 % unless the following character is such as not to need one.

 \def\smartitalicx{\ifx\next,\else\ifx\next-\else\ifx\next.\else

                     \ptexslash\fi\fi\fi}

 \def\smartslanted#1{{\ifusingtt\ttsl\sl #1}\futurelet\next\smartitalicx}

 \def\smartitalic#1{{\ifusingtt\ttsl\it #1}\futurelet\next\smartitalicx}

 \let\i=\smartitalic

 \let\var=\smartslanted

 \let\dfn=\smartslanted

 \let\emph=\smartitalic

 \let\cite=\smartslanted

 \def\b#1{{\bf #1}}

 \let\strong=\b

 % We can't just use \exhyphenpenalty, because that only has effect at

 % the end of a paragraph.  Restore normal hyphenation at the end of the

 % group within which \nohyphenation is presumably called.

 %

 \def\nohyphenation{\hyphenchar\font = -1  \aftergroup\restorehyphenation}

 \def\restorehyphenation{\hyphenchar\font = `- }

 % Set sfcode to normal for the chars that usually have another value.

 % Can't use plain's \frenchspacing because it uses the `\x notation, and

 % sometimes \x has an active definition that messes things up.

 %

 \catcode`@=11

   \def\frenchspacing{%

     \sfcode\dotChar  =\@m \sfcode\questChar=\@m \sfcode\exclamChar=\@m

     \sfcode\colonChar=\@m \sfcode\semiChar =\@m \sfcode\commaChar =\@m

   }

 \catcode`@=\other

 \def\t#1{%

   {\tt \rawbackslash \frenchspacing #1}%

   \null

 }

 \let\ttfont=\t

 \def\samp#1{`\tclose{#1}'\null}

 \setfont\keyrm\rmshape{8}{1000}

 \font\keysy=cmsy9

 \def\key#1{{\keyrm\textfont2=\keysy \leavevmode\hbox{%

   \raise0.4pt\hbox{\angleleft}\kern-.08em\vtop{%

     \vbox{\hrule\kern-0.4pt

      \hbox{\raise0.4pt\hbox{\vphantom{\angleleft}}#1}}%

     \kern-0.4pt\hrule}%

   \kern-.06em\raise0.4pt\hbox{\angleright}}}}

 % The old definition, with no lozenge:

 %\def\key #1{{\ttsl \nohyphenation \uppercase{#1}}\null}

 \def\ctrl #1{{\tt \rawbackslash \hat}#1}

 % @file, @option are the same as @samp.

 \let\file=\samp

 \let\option=\samp

 % @code is a modification of @t,

 % which makes spaces the same size as normal in the surrounding text.

 \def\tclose#1{%

   {%

     % Change normal interword space to be same as for the current font.

     \spaceskip = \fontdimen2\font

     %

     % Switch to typewriter.

     \tt

     %

     % But `\ ' produces the large typewriter interword space.

     \def\ {{\spaceskip = 0pt{} }}%

     %

     % Turn off hyphenation.

     \nohyphenation

     %

     \rawbackslash

     \frenchspacing

     #1%

   }%

   \null

 }

 % We *must* turn on hyphenation at `-' and `_' in \code.

 % Otherwise, it is too hard to avoid overfull hboxes

 % in the Emacs manual, the Library manual, etc.

 % Unfortunately, TeX uses one parameter (\hyphenchar) to control

 % both hyphenation at - and hyphenation within words.

 % We must therefore turn them both off (\tclose does that)

 % and arrange explicitly to hyphenate at a dash.

 %  -- rms.

 {

   \catcode`\-=\active

   \catcode`\_=\active

   %

   \global\def\code{\begingroup

     \catcode`\-=\active \let-\codedash

     \catcode`\_=\active \let_\codeunder

     \codex

   }

   %

   % If we end up with any active - characters when handling the index,

   % just treat them as a normal -.

   \global\def\indexbreaks{\catcode`\-=\active \let-\realdash}

 }

 \def\realdash{-}

 \def\codedash{-\discretionary{}{}{}}

 \def\codeunder{%

   % this is all so @math{@code{var_name}+1} can work.  In math mode, _

   % is "active" (mathcode"8000) and \normalunderscore (or \char95, etc.)

   % will therefore expand the active definition of _, which is us

   % (inside @code that is), therefore an endless loop.

   \ifusingtt{\ifmmode

                \mathchar"075F % class 0=ordinary, family 7=ttfam, pos 0x5F=_.

              \else\normalunderscore \fi

              \discretionary{}{}{}}%

             {\_}%

 }

 \def\codex #1{\tclose{#1}\endgroup}

 % @kbd is like @code, except that if the argument is just one @key command,

 % then @kbd has no effect.

 % @kbdinputstyle -- arg is `distinct' (@kbd uses slanted tty font always),

 %   `example' (@kbd uses ttsl only inside of @example and friends),

 %   or `code' (@kbd uses normal tty font always).

 \def\kbdinputstyle{\parsearg\kbdinputstylexxx}

 \def\kbdinputstylexxx#1{%

   \def\arg{#1}%

   \ifx\arg\worddistinct

     \gdef\kbdexamplefont{\ttsl}\gdef\kbdfont{\ttsl}%

   \else\ifx\arg\wordexample

     \gdef\kbdexamplefont{\ttsl}\gdef\kbdfont{\tt}%

   \else\ifx\arg\wordcode

     \gdef\kbdexamplefont{\tt}\gdef\kbdfont{\tt}%

   \else

     \errhelp = \EMsimple

     \errmessage{Unknown @kbdinputstyle option `\arg'}%

   \fi\fi\fi

 }

 \def\worddistinct{distinct}

 \def\wordexample{example}

 \def\wordcode{code}

 % Default is `distinct.'

 \kbdinputstyle distinct

 \def\xkey{\key}

 \def\kbdfoo#1#2#3\par{\def\one{#1}\def\three{#3}\def\threex{??}%

 \ifx\one\xkey\ifx\threex\three \key{#2}%

 \else{\tclose{\kbdfont\look}}\fi

 \else{\tclose{\kbdfont\look}}\fi}

 % For @url, @env, @command quotes seem unnecessary, so use \code.

 \let\url=\code

 \let\env=\code

 \let\command=\code

 % @uref (abbreviation for `urlref') takes an optional (comma-separated)

 % second argument specifying the text to display and an optional third

 % arg as text to display instead of (rather than in addition to) the url

 % itself.  First (mandatory) arg is the url.  Perhaps eventually put in

 % a hypertex \special here.

 %

 \def\uref#1{\douref #1,,,\finish}

 \def\douref#1,#2,#3,#4\finish{\begingroup

   \unsepspaces

   \pdfurl{#1}%

   \setbox0 = \hbox{\ignorespaces #3}%

   \ifdim\wd0 > 0pt

     \unhbox0 % third arg given, show only that

   \else

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

     \ifdim\wd0 > 0pt

       \ifpdf

         \unhbox0             % PDF: 2nd arg given, show only it

       \else

         \unhbox0\ (\code{#1})% DVI: 2nd arg given, show both it and url

       \fi

     \else

       \code{#1}% only url given, so show it

     \fi

   \fi

   \endlink

 \endgroup}

 % rms does not like angle brackets --karl, 17may97.

 % So now @email is just like @uref, unless we are pdf.

 %

 %\def\email#1{\angleleft{\tt #1}\angleright}

 \ifpdf

   \def\email#1{\doemail#1,,\finish}

   \def\doemail#1,#2,#3\finish{\begingroup

     \unsepspaces

     \pdfurl{mailto:#1}%

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

     \ifdim\wd0>0pt\unhbox0\else\code{#1}\fi

     \endlink

   \endgroup}

 \else

   \let\email=\uref

 \fi

 % Check if we are currently using a typewriter font.  Since all the

 % Computer Modern typewriter fonts have zero interword stretch (and

 % shrink), and it is reasonable to expect all typewriter fonts to have

 % this property, we can check that font parameter.

 %

 \def\ifmonospace{\ifdim\fontdimen3\font=0pt }

 % Typeset a dimension, e.g., `in' or `pt'.  The only reason for the

 % argument is to make the input look right: @dmn{pt} instead of @dmn{}pt.

 %

 \def\dmn#1{\thinspace #1}

 \def\kbd#1{\def\look{#1}\expandafter\kbdfoo\look??\par}

 % @l was never documented to mean ``switch to the Lisp font'',

 % and it is not used as such in any manual I can find.  We need it for

 % Polish suppressed-l.  --karl, 22sep96.

 %\def\l#1{{\li #1}\null}

 % Explicit font changes: @r, @sc, undocumented @ii.

 \def\r#1{{\rm #1}}              % roman font

 \def\sc#1{{\smallcaps#1}}       % smallcaps font

 \def\ii#1{{\it #1}}             % italic font

 % @acronym downcases the argument and prints in smallcaps.

 \def\acronym#1{{\smallcaps \lowercase{#1}}}

 % @pounds{} is a sterling sign.

 \def\pounds{{\it\$}}

 % @registeredsymbol - R in a circle.  For now, only works in text size;

 % we'd have to redo the font mechanism to change the \scriptstyle and

 % \scriptscriptstyle font sizes to make it look right in headings.

 % Adapted from the plain.tex definition of \copyright.

 %

 \def\registeredsymbol{%

   $^{{\ooalign{\hfil\raise.07ex\hbox{$\scriptstyle\rm R$}\hfil\crcr\Orb}}%

     }$%

 }

 \message{page headings,}

 \newskip\titlepagetopglue \titlepagetopglue = 1.5in

 \newskip\titlepagebottomglue \titlepagebottomglue = 2pc

 % First the title page.  Must do @settitle before @titlepage.

 \newif\ifseenauthor

 \newif\iffinishedtitlepage

 % Do an implicit @contents or @shortcontents after @end titlepage if the

 % user says @setcontentsaftertitlepage or @setshortcontentsaftertitlepage.

 %

 \newif\ifsetcontentsaftertitlepage

  \let\setcontentsaftertitlepage = \setcontentsaftertitlepagetrue

 \newif\ifsetshortcontentsaftertitlepage

  \let\setshortcontentsaftertitlepage = \setshortcontentsaftertitlepagetrue

 \def\shorttitlepage{\parsearg\shorttitlepagezzz}

 \def\shorttitlepagezzz #1{\begingroup\hbox{}\vskip 1.5in \chaprm \centerline{#1}%

         \endgroup\page\hbox{}\page}

 \def\titlepage{\begingroup \parindent=0pt \textfonts

    \let\subtitlerm=\tenrm

    \def\subtitlefont{\subtitlerm \normalbaselineskip = 13pt \normalbaselines}%

    %

    \def\authorfont{\authorrm \normalbaselineskip = 16pt \normalbaselines

                    \let\tt=\authortt}%

    %

    % Leave some space at the very top of the page.

    \vglue\titlepagetopglue

    %

    % Now you can print the title using @title.

    \def\title{\parsearg\titlezzz}%

    \def\titlezzz##1{\leftline{\titlefonts\rm ##1}

                     % print a rule at the page bottom also.

                     \finishedtitlepagefalse

                     \vskip4pt \hrule height 4pt width \hsize \vskip4pt}%

    % No rule at page bottom unless we print one at the top with @title.

    \finishedtitlepagetrue

    %

    % Now you can put text using @subtitle.

    \def\subtitle{\parsearg\subtitlezzz}%

    \def\subtitlezzz##1{{\subtitlefont \rightline{##1}}}%

    %

    % @author should come last, but may come many times.

    \def\author{\parsearg\authorzzz}%

    \def\authorzzz##1{\ifseenauthor\else\vskip 0pt plus 1filll\seenauthortrue\fi

       {\authorfont \leftline{##1}}}%

    %

    % Most title ``pages'' are actually two pages long, with space

    % at the top of the second.  We don't want the ragged left on the second.

    \let\oldpage = \page

    \def\page{%

       \iffinishedtitlepage\else

          \finishtitlepage

       \fi

       \oldpage

       \let\page = \oldpage

       \hbox{}}%

 %   \def\page{\oldpage \hbox{}}

 }

 \def\Etitlepage{%

    \iffinishedtitlepage\else

       \finishtitlepage

    \fi

    % It is important to do the page break before ending the group,

    % because the headline and footline are only empty inside the group.

    % If we use the new definition of \page, we always get a blank page

    % after the title page, which we certainly don't want.

    \oldpage

    \endgroup

    %

    % Need this before the \...aftertitlepage checks so that if they are

    % in effect the toc pages will come out with page numbers.

    \HEADINGSon

    %

    % If they want short, they certainly want long too.

    \ifsetshortcontentsaftertitlepage

      \shortcontents

      \contents

      \global\let\shortcontents = \relax

      \global\let\contents = \relax

    \fi

    %

    \ifsetcontentsaftertitlepage

      \contents

      \global\let\contents = \relax

      \global\let\shortcontents = \relax

    \fi

 }

 \def\finishtitlepage{%

    \vskip4pt \hrule height 2pt width \hsize

    \vskip\titlepagebottomglue

    \finishedtitlepagetrue

 }

 %%% Set up page headings and footings.

 \let\thispage=\folio

 \newtoks\evenheadline    % headline on even pages

 \newtoks\oddheadline     % headline on odd pages

 \newtoks\evenfootline    % footline on even pages

 \newtoks\oddfootline     % footline on odd pages

 % Now make Tex use those variables

 \headline={{\textfonts\rm \ifodd\pageno \the\oddheadline

                             \else \the\evenheadline \fi}}

 \footline={{\textfonts\rm \ifodd\pageno \the\oddfootline

                             \else \the\evenfootline \fi}\HEADINGShook}

 \let\HEADINGShook=\relax

 % Commands to set those variables.

 % For example, this is what  @headings on  does

 % @evenheading @thistitle|@thispage|@thischapter

 % @oddheading @thischapter|@thispage|@thistitle

 % @evenfooting @thisfile||

 % @oddfooting ||@thisfile

 \def\evenheading{\parsearg\evenheadingxxx}

 \def\oddheading{\parsearg\oddheadingxxx}

 \def\everyheading{\parsearg\everyheadingxxx}

 \def\evenfooting{\parsearg\evenfootingxxx}

 \def\oddfooting{\parsearg\oddfootingxxx}

 \def\everyfooting{\parsearg\everyfootingxxx}

 {\catcode`\@=0 %

 \gdef\evenheadingxxx #1{\evenheadingyyy #1@|@|@|@|\finish}

 \gdef\evenheadingyyy #1@|#2@|#3@|#4\finish{%

 \global\evenheadline={\rlap{\centerline{#2}}\line{#1\hfil#3}}}

 \gdef\oddheadingxxx #1{\oddheadingyyy #1@|@|@|@|\finish}

 \gdef\oddheadingyyy #1@|#2@|#3@|#4\finish{%

 \global\oddheadline={\rlap{\centerline{#2}}\line{#1\hfil#3}}}

 \gdef\everyheadingxxx#1{\oddheadingxxx{#1}\evenheadingxxx{#1}}%

 \gdef\evenfootingxxx #1{\evenfootingyyy #1@|@|@|@|\finish}

 \gdef\evenfootingyyy #1@|#2@|#3@|#4\finish{%

 \global\evenfootline={\rlap{\centerline{#2}}\line{#1\hfil#3}}}

 \gdef\oddfootingxxx #1{\oddfootingyyy #1@|@|@|@|\finish}

 \gdef\oddfootingyyy #1@|#2@|#3@|#4\finish{%

   \global\oddfootline = {\rlap{\centerline{#2}}\line{#1\hfil#3}}%

   %

   % Leave some space for the footline.  Hopefully ok to assume

   % @evenfooting will not be used by itself.

   \global\advance\pageheight by -\baselineskip

   \global\advance\vsize by -\baselineskip

 }

 \gdef\everyfootingxxx#1{\oddfootingxxx{#1}\evenfootingxxx{#1}}

 %

 }% unbind the catcode of @.

 % @headings double      turns headings on for double-sided printing.

 % @headings single      turns headings on for single-sided printing.

 % @headings off         turns them off.

 % @headings on          same as @headings double, retained for compatibility.

 % @headings after       turns on double-sided headings after this page.

 % @headings doubleafter turns on double-sided headings after this page.

 % @headings singleafter turns on single-sided headings after this page.

 % By default, they are off at the start of a document,

 % and turned `on' after @end titlepage.

 \def\headings #1 {\csname HEADINGS#1\endcsname}

 \def\HEADINGSoff{

 \global\evenheadline={\hfil} \global\evenfootline={\hfil}

 \global\oddheadline={\hfil} \global\oddfootline={\hfil}}

 \HEADINGSoff

 % When we turn headings on, set the page number to 1.

 % For double-sided printing, put current file name in lower left corner,

 % chapter name on inside top of right hand pages, document

 % title on inside top of left hand pages, and page numbers on outside top

 % edge of all pages.

 \def\HEADINGSdouble{

 \global\pageno=1

 \global\evenfootline={\hfil}

 \global\oddfootline={\hfil}

 \global\evenheadline={\line{\folio\hfil\thistitle}}

 \global\oddheadline={\line{\thischapter\hfil\folio}}

 \global\let\contentsalignmacro = \chapoddpage

 }

 \let\contentsalignmacro = \chappager

 % For single-sided printing, chapter title goes across top left of page,

 % page number on top right.

 \def\HEADINGSsingle{

 \global\pageno=1

 \global\evenfootline={\hfil}

 \global\oddfootline={\hfil}

 \global\evenheadline={\line{\thischapter\hfil\folio}}

 \global\oddheadline={\line{\thischapter\hfil\folio}}

 \global\let\contentsalignmacro = \chappager

 }

 \def\HEADINGSon{\HEADINGSdouble}

 \def\HEADINGSafter{\let\HEADINGShook=\HEADINGSdoublex}

 \let\HEADINGSdoubleafter=\HEADINGSafter

 \def\HEADINGSdoublex{%

 \global\evenfootline={\hfil}

 \global\oddfootline={\hfil}

 \global\evenheadline={\line{\folio\hfil\thistitle}}

 \global\oddheadline={\line{\thischapter\hfil\folio}}

 \global\let\contentsalignmacro = \chapoddpage

 }

 \def\HEADINGSsingleafter{\let\HEADINGShook=\HEADINGSsinglex}

 \def\HEADINGSsinglex{%

 \global\evenfootline={\hfil}

 \global\oddfootline={\hfil}

 \global\evenheadline={\line{\thischapter\hfil\folio}}

 \global\oddheadline={\line{\thischapter\hfil\folio}}

 \global\let\contentsalignmacro = \chappager

 }

 % Subroutines used in generating headings

 % This produces Day Month Year style of output.

 % Only define if not already defined, in case a txi-??.tex file has set

 % up a different format (e.g., txi-cs.tex does this).

 \ifx\today\undefined

 \def\today{%

   \number\day\space

   \ifcase\month

   \or\putwordMJan\or\putwordMFeb\or\putwordMMar\or\putwordMApr

   \or\putwordMMay\or\putwordMJun\or\putwordMJul\or\putwordMAug

   \or\putwordMSep\or\putwordMOct\or\putwordMNov\or\putwordMDec

   \fi

   \space\number\year}

 \fi

 % @settitle line...  specifies the title of the document, for headings.

 % It generates no output of its own.

 \def\thistitle{\putwordNoTitle}

 \def\settitle{\parsearg\settitlezzz}

 \def\settitlezzz #1{\gdef\thistitle{#1}}

 \message{tables,}

 % Tables -- @table, @ftable, @vtable, @item(x), @kitem(x), @xitem(x).

 % default indentation of table text

 \newdimen\tableindent \tableindent=.8in

 % default indentation of @itemize and @enumerate text

 \newdimen\itemindent  \itemindent=.3in

 % margin between end of table item and start of table text.

 \newdimen\itemmargin  \itemmargin=.1in

 % used internally for \itemindent minus \itemmargin

 \newdimen\itemmax

 % Note @table, @vtable, and @vtable define @item, @itemx, etc., with

 % these defs.

 % They also define \itemindex

 % to index the item name in whatever manner is desired (perhaps none).

 \newif\ifitemxneedsnegativevskip

 \def\itemxpar{\par\ifitemxneedsnegativevskip\nobreak\vskip-\parskip\nobreak\fi}

 \def\internalBitem{\smallbreak \parsearg\itemzzz}

 \def\internalBitemx{\itemxpar \parsearg\itemzzz}

 \def\internalBxitem "#1"{\def\xitemsubtopix{#1} \smallbreak \parsearg\xitemzzz}

 \def\internalBxitemx "#1"{\def\xitemsubtopix{#1} \itemxpar \parsearg\xitemzzz}

 \def\internalBkitem{\smallbreak \parsearg\kitemzzz}

 \def\internalBkitemx{\itemxpar \parsearg\kitemzzz}

 \def\kitemzzz #1{\dosubind {kw}{\code{#1}}{for {\bf \lastfunction}}%

                  \itemzzz {#1}}

 \def\xitemzzz #1{\dosubind {kw}{\code{#1}}{for {\bf \xitemsubtopic}}%

                  \itemzzz {#1}}

 \def\itemzzz #1{\begingroup %

   \advance\hsize by -\rightskip

   \advance\hsize by -\tableindent

   \setbox0=\hbox{\itemfont{#1}}%

   \itemindex{#1}%

   \nobreak % This prevents a break before @itemx.

   %

   % If the item text does not fit in the space we have, put it on a line

   % by itself, and do not allow a page break either before or after that

   % line.  We do not start a paragraph here because then if the next

   % command is, e.g., @kindex, the whatsit would get put into the

   % horizontal list on a line by itself, resulting in extra blank space.

   \ifdim \wd0>\itemmax

     %

     % Make this a paragraph so we get the \parskip glue and wrapping,

     % but leave it ragged-right.

     \begingroup

       \advance\leftskip by-\tableindent

       \advance\hsize by\tableindent

       \advance\rightskip by0pt plus1fil

       \leavevmode\unhbox0\par

     \endgroup

     %

     % We're going to be starting a paragraph, but we don't want the

     % \parskip glue -- logically it's part of the @item we just started.

     \nobreak \vskip-\parskip

     %

     % Stop a page break at the \parskip glue coming up.  (Unfortunately

     % we can't prevent a possible page break at the following

     % \baselineskip glue.)  However, if what follows is an environment

     % such as @example, there will be no \parskip glue; then

     % the negative vskip we just would cause the example and the item to

     % crash together.  So we use this bizarre value of 10001 as a signal

     % to \aboveenvbreak to insert \parskip glue after all.

     % (Possibly there are other commands that could be followed by

     % @example which need the same treatment, but not section titles; or

     % maybe section titles are the only special case and they should be

     % penalty 10001...)

     \penalty 10001

     \endgroup

     \itemxneedsnegativevskipfalse

   \else

     % The item text fits into the space.  Start a paragraph, so that the

     % following text (if any) will end up on the same line.

     \noindent

     % Do this with kerns and \unhbox so that if there is a footnote in

     % the item text, it can migrate to the main vertical list and

     % eventually be printed.

     \nobreak\kern-\tableindent

     \dimen0 = \itemmax  \advance\dimen0 by \itemmargin \advance\dimen0 by -\wd0

     \unhbox0

     \nobreak\kern\dimen0

     \endgroup

     \itemxneedsnegativevskiptrue

   \fi

 }

 \def\item{\errmessage{@item while not in a table}}

 \def\itemx{\errmessage{@itemx while not in a table}}

 \def\kitem{\errmessage{@kitem while not in a table}}

 \def\kitemx{\errmessage{@kitemx while not in a table}}

 \def\xitem{\errmessage{@xitem while not in a table}}

 \def\xitemx{\errmessage{@xitemx while not in a table}}

 % Contains a kludge to get @end[description] to work.

 \def\description{\tablez{\dontindex}{1}{}{}{}{}}

 % @table, @ftable, @vtable.

 \def\table{\begingroup\inENV\obeylines\obeyspaces\tablex}

 {\obeylines\obeyspaces%

 \gdef\tablex #1^^M{%

 \tabley\dontindex#1        \endtabley}}

 \def\ftable{\begingroup\inENV\obeylines\obeyspaces\ftablex}

 {\obeylines\obeyspaces%

 \gdef\ftablex #1^^M{%

 \tabley\fnitemindex#1        \endtabley

 \def\Eftable{\endgraf\afterenvbreak\endgroup}%

 \let\Etable=\relax}}

 \def\vtable{\begingroup\inENV\obeylines\obeyspaces\vtablex}

 {\obeylines\obeyspaces%

 \gdef\vtablex #1^^M{%

 \tabley\vritemindex#1        \endtabley

 \def\Evtable{\endgraf\afterenvbreak\endgroup}%

 \let\Etable=\relax}}

 \def\dontindex #1{}

 \def\fnitemindex #1{\doind {fn}{\code{#1}}}%

 \def\vritemindex #1{\doind {vr}{\code{#1}}}%

 {\obeyspaces %

 \gdef\tabley#1#2 #3 #4 #5 #6 #7\endtabley{\endgroup%

 \tablez{#1}{#2}{#3}{#4}{#5}{#6}}}

 \def\tablez #1#2#3#4#5#6{%

 \aboveenvbreak %

 \begingroup %

 \def\Edescription{\Etable}% Necessary kludge.

 \let\itemindex=#1%

 \ifnum 0#3>0 \advance \leftskip by #3\mil \fi %

 \ifnum 0#4>0 \tableindent=#4\mil \fi %

 \ifnum 0#5>0 \advance \rightskip by #5\mil \fi %

 \def\itemfont{#2}%

 \itemmax=\tableindent %

 \advance \itemmax by -\itemmargin %

 \advance \leftskip by \tableindent %

 \exdentamount=\tableindent

 \parindent = 0pt

 \parskip = \smallskipamount

 \ifdim \parskip=0pt \parskip=2pt \fi%

 \def\Etable{\endgraf\afterenvbreak\endgroup}%

 \let\item = \internalBitem %

 \let\itemx = \internalBitemx %

 \let\kitem = \internalBkitem %

 \let\kitemx = \internalBkitemx %

 \let\xitem = \internalBxitem %

 \let\xitemx = \internalBxitemx %

 }

 % This is the counter used by @enumerate, which is really @itemize

 \newcount \itemno

 \def\itemize{\parsearg\itemizezzz}

 \def\itemizezzz #1{%

   \begingroup % ended by the @end itemize

   \itemizey {#1}{\Eitemize}

 }

 \def\itemizey#1#2{%

   \aboveenvbreak

   \itemmax=\itemindent

   \advance\itemmax by -\itemmargin

   \advance\leftskip by \itemindent

   \exdentamount=\itemindent

   \parindent=0pt

   \parskip=\smallskipamount

   \ifdim\parskip=0pt \parskip=2pt \fi

   \def#2{\endgraf\afterenvbreak\endgroup}%

   \def\itemcontents{#1}%

   % @itemize with no arg is equivalent to @itemize @bullet.

   \ifx\itemcontents\empty\def\itemcontents{\bullet}\fi

   \let\item=\itemizeitem

 }

 % \splitoff TOKENS\endmark defines \first to be the first token in

 % TOKENS, and \rest to be the remainder.

 %

 \def\splitoff#1#2\endmark{\def\first{#1}\def\rest{#2}}%

 % Allow an optional argument of an uppercase letter, lowercase letter,

 % or number, to specify the first label in the enumerated list.  No

 % argument is the same as `1'.

 %

 \def\enumerate{\parsearg\enumeratezzz}

 \def\enumeratezzz #1{\enumeratey #1  \endenumeratey}

 \def\enumeratey #1 #2\endenumeratey{%

   \begingroup % ended by the @end enumerate

   %

   % If we were given no argument, pretend we were given `1'.

   \def\thearg{#1}%

   \ifx\thearg\empty \def\thearg{1}\fi

   %

   % Detect if the argument is a single token.  If so, it might be a

   % letter.  Otherwise, the only valid thing it can be is a number.

   % (We will always have one token, because of the test we just made.

   % This is a good thing, since \splitoff doesn't work given nothing at

   % all -- the first parameter is undelimited.)

   \expandafter\splitoff\thearg\endmark

   \ifx\rest\empty

     % Only one token in the argument.  It could still be anything.

     % A ``lowercase letter'' is one whose \lccode is nonzero.

     % An ``uppercase letter'' is one whose \lccode is both nonzero, and

     %   not equal to itself.

     % Otherwise, we assume it's a number.

     %

     % We need the \relax at the end of the \ifnum lines to stop TeX from

     % continuing to look for a <number>.

     %

     \ifnum\lccode\expandafter`\thearg=0\relax

       \numericenumerate % a number (we hope)

     \else

       % It's a letter.

       \ifnum\lccode\expandafter`\thearg=\expandafter`\thearg\relax

         \lowercaseenumerate % lowercase letter

       \else

         \uppercaseenumerate % uppercase letter

       \fi

     \fi

   \else

     % Multiple tokens in the argument.  We hope it's a number.

     \numericenumerate

   \fi

 }

 % An @enumerate whose labels are integers.  The starting integer is

 % given in \thearg.

 %

 \def\numericenumerate{%

   \itemno = \thearg

   \startenumeration{\the\itemno}%

 }

 % The starting (lowercase) letter is in \thearg.

 \def\lowercaseenumerate{%

   \itemno = \expandafter`\thearg

   \startenumeration{%

     % Be sure we're not beyond the end of the alphabet.

     \ifnum\itemno=0

       \errmessage{No more lowercase letters in @enumerate; get a bigger

                   alphabet}%

     \fi

     \char\lccode\itemno

   }%

 }

 % The starting (uppercase) letter is in \thearg.

 \def\uppercaseenumerate{%

   \itemno = \expandafter`\thearg

   \startenumeration{%

     % Be sure we're not beyond the end of the alphabet.

     \ifnum\itemno=0

       \errmessage{No more uppercase letters in @enumerate; get a bigger

                   alphabet}

     \fi

     \char\uccode\itemno

   }%

 }

 % Call itemizey, adding a period to the first argument and supplying the

 % common last two arguments.  Also subtract one from the initial value in

 % \itemno, since @item increments \itemno.

 %

 \def\startenumeration#1{%

   \advance\itemno by -1

   \itemizey{#1.}\Eenumerate\flushcr

 }

 % @alphaenumerate and @capsenumerate are abbreviations for giving an arg

 % to @enumerate.

 %

 \def\alphaenumerate{\enumerate{a}}

 \def\capsenumerate{\enumerate{A}}

 \def\Ealphaenumerate{\Eenumerate}

 \def\Ecapsenumerate{\Eenumerate}

 % Definition of @item while inside @itemize.

 \def\itemizeitem{%

 \advance\itemno by 1

 {\let\par=\endgraf \smallbreak}%

 \ifhmode \errmessage{In hmode at itemizeitem}\fi

 {\parskip=0in \hskip 0pt

 \hbox to 0pt{\hss \itemcontents\hskip \itemmargin}%

 \vadjust{\penalty 1200}}%

 \flushcr}

 % @multitable macros

 % Amy Hendrickson, 8/18/94, 3/6/96

 %

 % @multitable ... @end multitable will make as many columns as desired.

 % Contents of each column will wrap at width given in preamble.  Width

 % can be specified either with sample text given in a template line,

 % or in percent of \hsize, the current width of text on page.

 % Table can continue over pages but will only break between lines.

 % To make preamble:

 %

 % Either define widths of columns in terms of percent of \hsize:

 %   @multitable @columnfractions .25 .3 .45

 %   @item ...

 %

 %   Numbers following @columnfractions are the percent of the total

 %   current hsize to be used for each column. You may use as many

 %   columns as desired.

 % Or use a template:

 %   @multitable {Column 1 template} {Column 2 template} {Column 3 template}

 %   @item ...

 %   using the widest term desired in each column.

 %

 % For those who want to use more than one line's worth of words in

 % the preamble, break the line within one argument and it

 % will parse correctly, i.e.,

 %

 %     @multitable {Column 1 template} {Column 2 template} {Column 3

 %      template}

 % Not:

 %     @multitable {Column 1 template} {Column 2 template}

 %      {Column 3 template}

 % Each new table line starts with @item, each subsequent new column

 % starts with @tab. Empty columns may be produced by supplying @tab's

 % with nothing between them for as many times as empty columns are needed,

 % ie, @tab@tab@tab will produce two empty columns.

 % @item, @tab, @multitable or @end multitable do not need to be on their

 % own lines, but it will not hurt if they are.

 % Sample multitable:

 %   @multitable {Column 1 template} {Column 2 template} {Column 3 template}

 %   @item first col stuff @tab second col stuff @tab third col

 %   @item

 %   first col stuff

 %   @tab

 %   second col stuff

 %   @tab

 %   third col

 %   @item first col stuff @tab second col stuff

 %   @tab Many paragraphs of text may be used in any column.

 %

 %         They will wrap at the width determined by the template.

 %   @item@tab@tab This will be in third column.

 %   @end multitable

 % Default dimensions may be reset by user.

 % @multitableparskip is vertical space between paragraphs in table.

 % @multitableparindent is paragraph indent in table.

 % @multitablecolmargin is horizontal space to be left between columns.

 % @multitablelinespace is space to leave between table items, baseline

 %                                                            to baseline.

 %   0pt means it depends on current normal line spacing.

 %

 \newskip\multitableparskip

 \newskip\multitableparindent

 \newdimen\multitablecolspace

 \newskip\multitablelinespace

 \multitableparskip=0pt

 \multitableparindent=6pt

 \multitablecolspace=12pt

 \multitablelinespace=0pt

 % Macros used to set up halign preamble:

 %

 \let\endsetuptable\relax

 \def\xendsetuptable{\endsetuptable}

 \let\columnfractions\relax

 \def\xcolumnfractions{\columnfractions}

 \newif\ifsetpercent

 % #1 is the part of the @columnfraction before the decimal point, which

 % is presumably either 0 or the empty string (but we don't check, we

 % just throw it away).  #2 is the decimal part, which we use as the

 % percent of \hsize for this column.

 \def\pickupwholefraction#1.#2 {%

   \global\advance\colcount by 1

   \expandafter\xdef\csname col\the\colcount\endcsname{.#2\hsize}%

   \setuptable

 }

 \newcount\colcount

 \def\setuptable#1{%

   \def\firstarg{#1}%

   \ifx\firstarg\xendsetuptable

     \let\go = \relax

   \else

     \ifx\firstarg\xcolumnfractions

       \global\setpercenttrue

     \else

       \ifsetpercent

          \let\go\pickupwholefraction

       \else

          \global\advance\colcount by 1

          \setbox0=\hbox{#1\unskip\space}% Add a normal word space as a

                    % separator; typically that is always in the input, anyway.

          \expandafter\xdef\csname col\the\colcount\endcsname{\the\wd0}%

       \fi

     \fi

     \ifx\go\pickupwholefraction

       % Put the argument back for the \pickupwholefraction call, so

       % we'll always have a period there to be parsed.

       \def\go{\pickupwholefraction#1}%

     \else

       \let\go = \setuptable

     \fi%

   \fi

   \go

 }

 % @multitable ... @end multitable definitions:

 %

 \def\multitable{\parsearg\dotable}

 \def\dotable#1{\bgroup

   \vskip\parskip

   \let\item=\crcrwithfootnotes

   % A \tab used to include \hskip1sp.  But then the space in a template

   % line is not enough.  That is bad.  So let's go back to just & until

   % we encounter the problem it was intended to solve again.  --karl,

   % nathan@acm.org, 20apr99.

   \let\tab=&%

   \let\startfootins=\startsavedfootnote

   \tolerance=9500

   \hbadness=9500

   \setmultitablespacing

   \parskip=\multitableparskip

   \parindent=\multitableparindent

   \overfullrule=0pt

   \global\colcount=0

   \def\Emultitable{%

     \global\setpercentfalse

     \crcrwithfootnotes\crcr

     \egroup\egroup

   }%

   %

   % To parse everything between @multitable and @item:

   \setuptable#1 \endsetuptable

   %

   % \everycr will reset column counter, \colcount, at the end of

   % each line. Every column entry will cause \colcount to advance by one.

   % The table preamble

   % looks at the current \colcount to find the correct column width.

   \everycr{\noalign{%

   %

   % \filbreak%% keeps underfull box messages off when table breaks over pages.

   % Maybe so, but it also creates really weird page breaks when the table

   % breaks over pages. Wouldn't \vfil be better?  Wait until the problem

   % manifests itself, so it can be fixed for real --karl.

     \global\colcount=0\relax}}%

   %

   % This preamble sets up a generic column definition, which will

   % be used as many times as user calls for columns.

   % \vtop will set a single line and will also let text wrap and

   % continue for many paragraphs if desired.

   \halign\bgroup&\global\advance\colcount by 1\relax

     \multistrut\vtop{\hsize=\expandafter\csname col\the\colcount\endcsname

   %

   % In order to keep entries from bumping into each other

   % we will add a \leftskip of \multitablecolspace to all columns after

   % the first one.

   %

   % If a template has been used, we will add \multitablecolspace

   % to the width of each template entry.

   %

   % If the user has set preamble in terms of percent of \hsize we will

   % use that dimension as the width of the column, and the \leftskip

   % will keep entries from bumping into each other.  Table will start at

   % left margin and final column will justify at right margin.

   %

   % Make sure we don't inherit \rightskip from the outer environment.

   \rightskip=0pt

   \ifnum\colcount=1

     % The first column will be indented with the surrounding text.

     \advance\hsize by\leftskip

   \else

     \ifsetpercent \else

       % If user has not set preamble in terms of percent of \hsize

       % we will advance \hsize by \multitablecolspace.

       \advance\hsize by \multitablecolspace

     \fi

    % In either case we will make \leftskip=\multitablecolspace:

   \leftskip=\multitablecolspace

   \fi

   % Ignoring space at the beginning and end avoids an occasional spurious

   % blank line, when TeX decides to break the line at the space before the

   % box from the multistrut, so the strut ends up on a line by itself.

   % For example:

   % @multitable @columnfractions .11 .89

   % @item @code{#}

   % @tab Legal holiday which is valid in major parts of the whole country.

   % Is automatically provided with highlighting sequences respectively marking

   % characters.

   \noindent\ignorespaces##\unskip\multistrut}\cr

 }

 \def\setmultitablespacing{% test to see if user has set \multitablelinespace.

 % If so, do nothing. If not, give it an appropriate dimension based on

 % current baselineskip.

 \ifdim\multitablelinespace=0pt

 \setbox0=\vbox{X}\global\multitablelinespace=\the\baselineskip

 \global\advance\multitablelinespace by-\ht0

 %% strut to put in table in case some entry doesn't have descenders,

 %% to keep lines equally spaced

 \let\multistrut = \strut

 \else

 %% FIXME: what is \box0 supposed to be?

 \gdef\multistrut{\vrule height\multitablelinespace depth\dp0

 width0pt\relax} \fi

 %% Test to see if parskip is larger than space between lines of

 %% table. If not, do nothing.

 %%        If so, set to same dimension as multitablelinespace.

 \ifdim\multitableparskip>\multitablelinespace

 \global\multitableparskip=\multitablelinespace

 \global\advance\multitableparskip-7pt %% to keep parskip somewhat smaller

                                       %% than skip between lines in the table.

 \fi%

 \ifdim\multitableparskip=0pt

 \global\multitableparskip=\multitablelinespace

 \global\advance\multitableparskip-7pt %% to keep parskip somewhat smaller

                                       %% than skip between lines in the table.

 \fi}

 % In case a @footnote appears inside an alignment, save the footnote

 % text to a box and make the \insert when a row of the table is

 % finished.  Otherwise, the insertion is lost, it never migrates to the

 % main vertical list.  --kasal, 22jan03.

 %

 \newbox\savedfootnotes

 %

 % \dotable \let's \startfootins to this, so that \dofootnote will call

 % it instead of starting the insertion right away.

 \def\startsavedfootnote{%

   \global\setbox\savedfootnotes = \vbox\bgroup

     \unvbox\savedfootnotes

 }

 \def\crcrwithfootnotes{%

   \crcr

   \ifvoid\savedfootnotes \else

     \noalign{\insert\footins{\box\savedfootnotes}}%

   \fi

 }

 \message{conditionals,}

 % Prevent errors for section commands.

 % Used in @ignore and in failing conditionals.

 \def\ignoresections{%

   \let\appendix=\relax

   \let\appendixsec=\relax

   \let\appendixsection=\relax

   \let\appendixsubsec=\relax

   \let\appendixsubsection=\relax

   \let\appendixsubsubsec=\relax

   \let\appendixsubsubsection=\relax

   %\let\begin=\relax

   %\let\bye=\relax

   \let\centerchap=\relax

   \let\chapter=\relax

   \let\contents=\relax

   \let\section=\relax

   \let\smallbook=\relax

   \let\subsec=\relax

   \let\subsection=\relax

   \let\subsubsec=\relax

   \let\subsubsection=\relax

   \let\titlepage=\relax

   \let\top=\relax

   \let\unnumbered=\relax

   \let\unnumberedsec=\relax

   \let\unnumberedsection=\relax

   \let\unnumberedsubsec=\relax

   \let\unnumberedsubsection=\relax

   \let\unnumberedsubsubsec=\relax

   \let\unnumberedsubsubsection=\relax

 }

 % Ignore @ignore, @ifhtml, @ifinfo, and the like.

 %

 \def\direntry{\doignore{direntry}}

 \def\documentdescriptionword{documentdescription}

 \def\documentdescription{\doignore{documentdescription}}

 \def\html{\doignore{html}}

 \def\ifhtml{\doignore{ifhtml}}

 \def\ifinfo{\doignore{ifinfo}}

 \def\ifnottex{\doignore{ifnottex}}

 \def\ifplaintext{\doignore{ifplaintext}}

 \def\ifxml{\doignore{ifxml}}

 \def\ignore{\doignore{ignore}}

 \def\menu{\doignore{menu}}

 \def\xml{\doignore{xml}}

 % @dircategory CATEGORY  -- specify a category of the dir file

 % which this file should belong to.  Ignore this in TeX.

 \let\dircategory = \comment

 % Ignore text until a line `@end #1', keeping track of nested conditionals.

 %

 % A count to remember the depth of nesting.

 \newcount\doignorecount  \doignorecount = 0

 \def\doignore#1{\begingroup

   % Don't complain about control sequences we have declared \outer.

   \ignoresections

   %

   % Make sure that spaces turn into tokens that match what \doignoretext wants.

   \catcode\spaceChar = 10

   %

   % Ignore braces, so mismatched braces don't cause trouble.

   \catcode`\{ = 9

   \catcode`\} = 9

   %

   % Count number of #1's that we've seen.

   \doignorecount = 0

   %

   % Swallow text until we reach the matching `@end #1'.

   \expandafter \dodoignore \csname#1\endcsname {#1}%

 }

 { \catcode`@=11 % We want to use \ST@P which cannot appear in texinfo source.

   \obeylines %

   %

   \gdef\dodoignore#1#2{%

     % #1 contains, e.g., \ifinfo, a.k.a. @ifinfo.

     % #2 contains the string `ifinfo'.

     %

     % Define a command to find the next `@end #2', which must be on a line

     % by itself.

     \long\def\doignoretext##1^^M\end #2{\doignoretextyyy##1^^M#1\ST@P}%

     % And this command to find another #1 command, at the beginning of a

     % line.  (Otherwise, we would consider a line `@c @ifset', for

     % example, to count as an @ifset for nesting.)

     \long\def\doignoretextyyy##1^^M#1##2\ST@P{\doignoreyyy{##2}\ST@P}%

     %

     % And now expand that command.

     \obeylines %

     \doignoretext ^^M%

   }%

 }

 \def\doignoreyyy#1{%

   \def\temp{#1}%

   \ifx\temp\empty			% Nothing found.

     \let\next\doignoretextzzz

   \else					% Found a nested condition, ...

     \advance\doignorecount by 1

     \let\next\doignoretextyyy		% ..., look for another.

     % If we're here, #1 ends with \ifinfo (for example).

   \fi

   \next #1% the token \ST@P is present just after this macro.

 }

 % We have to swallow the remaining "\ST@P".

 % 

 \def\doignoretextzzz#1{%

   \ifnum\doignorecount = 0	% We have just found the outermost @end.

     \let\next\enddoignore

   \else				% Still inside a nested condition.

     \advance\doignorecount by -1

     \let\next\doignoretext      % Look for the next @end.

   \fi

   \next

 }

 % Finish off ignored text.

 \def\enddoignore{\endgroup\ignorespaces}

 % @set VAR sets the variable VAR to an empty value.

 % @set VAR REST-OF-LINE sets VAR to the value REST-OF-LINE.

 %

 % Since we want to separate VAR from REST-OF-LINE (which might be

 % empty), we can't just use \parsearg; we have to insert a space of our

 % own to delimit the rest of the line, and then take it out again if we

 % didn't need it.  Make sure the catcode of space is correct to avoid