+\message{conditionals,}
+% Prevent errors for section commands.
+% Used in @ignore and in failing conditionals.
+\def\ignoresections{%
+ \let\chapter=\relax
+ \let\unnumbered=\relax
+ \let\top=\relax
+ \let\unnumberedsec=\relax
+ \let\unnumberedsection=\relax
+ \let\unnumberedsubsec=\relax
+ \let\unnumberedsubsection=\relax
+ \let\unnumberedsubsubsec=\relax
+ \let\unnumberedsubsubsection=\relax
+ \let\section=\relax
+ \let\subsec=\relax
+ \let\subsubsec=\relax
+ \let\subsection=\relax
+ \let\subsubsection=\relax
+ \let\appendix=\relax
+ \let\appendixsec=\relax
+ \let\appendixsection=\relax
+ \let\appendixsubsec=\relax
+ \let\appendixsubsection=\relax
+ \let\appendixsubsubsec=\relax
+ \let\appendixsubsubsection=\relax
+ \let\contents=\relax
+ \let\smallbook=\relax
+ \let\titlepage=\relax
+}
+
+% Used in nested conditionals, where we have to parse the Texinfo source
+% and so want to turn off most commands, in case they are used
+% incorrectly.
+%
+\def\ignoremorecommands{%
+ \let\defcodeindex = \relax
+ \let\defcv = \relax
+ \let\deffn = \relax
+ \let\deffnx = \relax
+ \let\defindex = \relax
+ \let\defivar = \relax
+ \let\defmac = \relax
+ \let\defmethod = \relax
+ \let\defop = \relax
+ \let\defopt = \relax
+ \let\defspec = \relax
+ \let\deftp = \relax
+ \let\deftypefn = \relax
+ \let\deftypefun = \relax
+ \let\deftypeivar = \relax
+ \let\deftypeop = \relax
+ \let\deftypevar = \relax
+ \let\deftypevr = \relax
+ \let\defun = \relax
+ \let\defvar = \relax
+ \let\defvr = \relax
+ \let\ref = \relax
+ \let\xref = \relax
+ \let\printindex = \relax
+ \let\pxref = \relax
+ \let\settitle = \relax
+ \let\setchapternewpage = \relax
+ \let\setchapterstyle = \relax
+ \let\everyheading = \relax
+ \let\evenheading = \relax
+ \let\oddheading = \relax
+ \let\everyfooting = \relax
+ \let\evenfooting = \relax
+ \let\oddfooting = \relax
+ \let\headings = \relax
+ \let\include = \relax
+ \let\lowersections = \relax
+ \let\down = \relax
+ \let\raisesections = \relax
+ \let\up = \relax
+ \let\set = \relax
+ \let\clear = \relax
+ \let\item = \relax
+}
+
+% Ignore @ignore ... @end ignore.
+%
+\def\ignore{\doignore{ignore}}
+
+% Ignore @ifinfo, @ifhtml, @ifnottex, @html, @menu, and @direntry text.
+%
+\def\ifinfo{\doignore{ifinfo}}
+\def\ifhtml{\doignore{ifhtml}}
+\def\ifnottex{\doignore{ifnottex}}
+\def\html{\doignore{html}}
+\def\menu{\doignore{menu}}
+\def\direntry{\doignore{direntry}}
+
+% @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'.
+%
+\def\doignore#1{\begingroup
+ % Don't complain about control sequences we have declared \outer.
+ \ignoresections
+ %
+ % Define a command to swallow text until we reach `@end #1'.
+ % This @ is a catcode 12 token (that is the normal catcode of @ in
+ % this texinfo.tex file). We change the catcode of @ below to match.
+ \long\def\doignoretext##1@end #1{\enddoignore}%
+ %
+ % Make sure that spaces turn into tokens that match what \doignoretext wants.
+ \catcode32 = 10
+ %
+ % Ignore braces, too, so mismatched braces don't cause trouble.
+ \catcode`\{ = 9
+ \catcode`\} = 9
+ %
+ % We must not have @c interpreted as a control sequence.
+ \catcode`\@ = 12
+ %
+ % Make the letter c a comment character so that the rest of the line
+ % will be ignored. This way, the document can have (for example)
+ % @c @end ifinfo
+ % and the @end ifinfo will be properly ignored.
+ % (We've just changed @ to catcode 12.)
+ \catcode`\c = 14
+ %
+ % And now expand that command.
+ \doignoretext
+}
+
+% What we do to finish off ignored text.
+%
+\def\enddoignore{\endgroup\ignorespaces}%
+
+\newif\ifwarnedobs\warnedobsfalse
+\def\obstexwarn{%
+ \ifwarnedobs\relax\else
+ % We need to warn folks that they may have trouble with TeX 3.0.
+ % This uses \immediate\write16 rather than \message to get newlines.
+ \immediate\write16{}
+ \immediate\write16{WARNING: for users of Unix TeX 3.0!}
+ \immediate\write16{This manual trips a bug in TeX version 3.0 (tex hangs).}
+ \immediate\write16{If you are running another version of TeX, relax.}
+ \immediate\write16{If you are running Unix TeX 3.0, kill this TeX process.}
+ \immediate\write16{ Then upgrade your TeX installation if you can.}
+ \immediate\write16{ (See ftp://ftp.gnu.org/pub/gnu/TeX.README.)}
+ \immediate\write16{If you are stuck with version 3.0, run the}
+ \immediate\write16{ script ``tex3patch'' from the Texinfo distribution}
+ \immediate\write16{ to use a workaround.}
+ \immediate\write16{}
+ \global\warnedobstrue
+ \fi
+}
+
+% **In TeX 3.0, setting text in \nullfont hangs tex. For a
+% workaround (which requires the file ``dummy.tfm'' to be installed),
+% uncomment the following line:
+%%%%%\font\nullfont=dummy\let\obstexwarn=\relax
+
+% Ignore text, except that we keep track of conditional commands for
+% purposes of nesting, up to an `@end #1' command.
+%
+\def\nestedignore#1{%
+ \obstexwarn
+ % We must actually expand the ignored text to look for the @end
+ % command, so that nested ignore constructs work. Thus, we put the
+ % text into a \vbox and then do nothing with the result. To minimize
+ % the change of memory overflow, we follow the approach outlined on
+ % page 401 of the TeXbook: make the current font be a dummy font.
+ %
+ \setbox0 = \vbox\bgroup
+ % Don't complain about control sequences we have declared \outer.
+ \ignoresections
+ %
+ % Define `@end #1' to end the box, which will in turn undefine the
+ % @end command again.
+ \expandafter\def\csname E#1\endcsname{\egroup\ignorespaces}%
+ %
+ % We are going to be parsing Texinfo commands. Most cause no
+ % trouble when they are used incorrectly, but some commands do
+ % complicated argument parsing or otherwise get confused, so we
+ % undefine them.
+ %
+ % We can't do anything about stray @-signs, unfortunately;
+ % they'll produce `undefined control sequence' errors.
+ \ignoremorecommands
+ %
+ % Set the current font to be \nullfont, a TeX primitive, and define
+ % all the font commands to also use \nullfont. We don't use
+ % dummy.tfm, as suggested in the TeXbook, because not all sites
+ % might have that installed. Therefore, math mode will still
+ % produce output, but that should be an extremely small amount of
+ % stuff compared to the main input.
+ %
+ \nullfont
+ \let\tenrm=\nullfont \let\tenit=\nullfont \let\tensl=\nullfont
+ \let\tenbf=\nullfont \let\tentt=\nullfont \let\smallcaps=\nullfont
+ \let\tensf=\nullfont
+ % Similarly for index fonts (mostly for their use in smallexample).
+ \let\smallrm=\nullfont \let\smallit=\nullfont \let\smallsl=\nullfont
+ \let\smallbf=\nullfont \let\smalltt=\nullfont \let\smallsc=\nullfont
+ \let\smallsf=\nullfont
+ %
+ % Don't complain when characters are missing from the fonts.
+ \tracinglostchars = 0
+ %
+ % Don't bother to do space factor calculations.
+ \frenchspacing
+ %
+ % Don't report underfull hboxes.
+ \hbadness = 10000
+ %
+ % Do minimal line-breaking.
+ \pretolerance = 10000
+ %
+ % Do not execute instructions in @tex
+ \def\tex{\doignore{tex}}%
+ % Do not execute macro definitions.
+ % `c' is a comment character, so the word `macro' will get cut off.
+ \def\macro{\doignore{ma}}%
+}
+
+% @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
+% losing inside @example, for instance.
+%
+\def\set{\begingroup\catcode` =10
+ \catcode`\-=12 \catcode`\_=12 % Allow - and _ in VAR.
+ \parsearg\setxxx}
+\def\setxxx#1{\setyyy#1 \endsetyyy}
+\def\setyyy#1 #2\endsetyyy{%
+ \def\temp{#2}%
+ \ifx\temp\empty \global\expandafter\let\csname SET#1\endcsname = \empty
+ \else \setzzz{#1}#2\endsetzzz % Remove the trailing space \setxxx inserted.
+ \fi
+ \endgroup
+}
+% Can't use \xdef to pre-expand #2 and save some time, since \temp or
+% \next or other control sequences that we've defined might get us into
+% an infinite loop. Consider `@set foo @cite{bar}'.
+\def\setzzz#1#2 \endsetzzz{\expandafter\gdef\csname SET#1\endcsname{#2}}
+
+% @clear VAR clears (i.e., unsets) the variable VAR.
+%
+\def\clear{\parsearg\clearxxx}
+\def\clearxxx#1{\global\expandafter\let\csname SET#1\endcsname=\relax}
+
+% @value{foo} gets the text saved in variable foo.
+{
+ \catcode`\_ = \active
+ %
+ % We might end up with active _ or - characters in the argument if
+ % we're called from @code, as @code{@value{foo-bar_}}. So \let any
+ % such active characters to their normal equivalents.
+ \gdef\value{\begingroup
+ \catcode`\-=12 \catcode`\_=12
+ \indexbreaks \let_\normalunderscore
+ \valuexxx}
+}
+\def\valuexxx#1{\expandablevalue{#1}\endgroup}
+
+% We have this subroutine so that we can handle at least some @value's
+% properly in indexes (we \let\value to this in \indexdummies). Ones
+% whose names contain - or _ still won't work, but we can't do anything
+% about that. The command has to be fully expandable, since the result
+% winds up in the index file. This means that if the variable's value
+% contains other Texinfo commands, it's almost certain it will fail
+% (although perhaps we could fix that with sufficient work to do a
+% one-level expansion on the result, instead of complete).
+%
+\def\expandablevalue#1{%
+ \expandafter\ifx\csname SET#1\endcsname\relax
+ {[No value for ``#1'']}%
+ \else
+ \csname SET#1\endcsname
+ \fi
+}
+
+% @ifset VAR ... @end ifset reads the `...' iff VAR has been defined
+% with @set.
+%
+\def\ifset{\parsearg\ifsetxxx}
+\def\ifsetxxx #1{%
+ \expandafter\ifx\csname SET#1\endcsname\relax
+ \expandafter\ifsetfail
+ \else
+ \expandafter\ifsetsucceed
+ \fi
+}
+\def\ifsetsucceed{\conditionalsucceed{ifset}}
+\def\ifsetfail{\nestedignore{ifset}}
+\defineunmatchedend{ifset}
+
+% @ifclear VAR ... @end ifclear reads the `...' iff VAR has never been
+% defined with @set, or has been undefined with @clear.
+%
+\def\ifclear{\parsearg\ifclearxxx}
+\def\ifclearxxx #1{%
+ \expandafter\ifx\csname SET#1\endcsname\relax
+ \expandafter\ifclearsucceed
+ \else
+ \expandafter\ifclearfail
+ \fi
+}
+\def\ifclearsucceed{\conditionalsucceed{ifclear}}
+\def\ifclearfail{\nestedignore{ifclear}}
+\defineunmatchedend{ifclear}
+
+% @iftex, @ifnothtml, @ifnotinfo always succeed; we read the text
+% following, through the first @end iftex (etc.). Make `@end iftex'
+% (etc.) valid only after an @iftex.
+%
+\def\iftex{\conditionalsucceed{iftex}}
+\def\ifnothtml{\conditionalsucceed{ifnothtml}}
+\def\ifnotinfo{\conditionalsucceed{ifnotinfo}}
+\defineunmatchedend{iftex}
+\defineunmatchedend{ifnothtml}
+\defineunmatchedend{ifnotinfo}
+
+% We can't just want to start a group at @iftex (for example) and end it
+% at @end iftex, since then @set commands inside the conditional have no
+% effect (they'd get reverted at the end of the group). So we must
+% define \Eiftex to redefine itself to be its previous value. (We can't
+% just define it to fail again with an ``unmatched end'' error, since
+% the @ifset might be nested.)
+%
+\def\conditionalsucceed#1{%
+ \edef\temp{%
+ % Remember the current value of \E#1.
+ \let\nece{prevE#1} = \nece{E#1}%
+ %
+ % At the `@end #1', redefine \E#1 to be its previous value.
+ \def\nece{E#1}{\let\nece{E#1} = \nece{prevE#1}}%
+ }%
+ \temp
+}
+
+% We need to expand lots of \csname's, but we don't want to expand the
+% control sequences after we've constructed them.
+%
+\def\nece#1{\expandafter\noexpand\csname#1\endcsname}
+
+% @defininfoenclose.
+\let\definfoenclose=\comment
+
+