https://github.com/latex3/latex2e
Tip revision: 19b9416ae8e1e83a814f13da645414bad4d61adf authored by Joseph Wright on 29 February 2024, 08:45:07 UTC
Add firstaid for chemnum
Add firstaid for chemnum
Tip revision: 19b9416
ltdefns.dtx
% \iffalse meta-comment
%
% Copyright (C) 1993-2024
% The LaTeX Project and any individual authors listed elsewhere
% in this file.
%
% This file is part of the LaTeX base system.
% -------------------------------------------
%
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
% https://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008 or later.
%
% This file has the LPPL maintenance status "maintained".
%
% The list of all files belonging to the LaTeX base distribution is
% given in the file `manifest.txt'. See also `legal.txt' for additional
% information.
%
% The list of derived (unpacked) files belonging to the distribution
% and covered by LPPL is defined by the unpacking scripts (with
% extension .ins) which are part of the distribution.
%
% \fi
%
% \iffalse
%%% From File: ltdefns.dtx
%<*driver>
% \fi
\ProvidesFile{ltdefns.dtx}
[2022/11/24 v1.5s LaTeX Kernel (definition commands)]
% \iffalse
\documentclass{ltxdoc}
\GetFileInfo{ltdefns.dtx}
\title{\filename}
\date{\filedate}
\author{%
Johannes Braams\and
David Carlisle\and
Alan Jeffrey\and
Leslie Lamport\and
Frank Mittelbach\and
Chris Rowley\and
Rainer Sch\"opf}
\begin{document}
\MaintainedByLaTeXTeam{latex}
\maketitle
\DocInput{\filename}
\end{document}
%</driver>
% \fi
%
%
% \changes{v1.0n}{1994/05/10}{(ASAJ) Added
% \cs{DeclareProtectedCommand}.}
% \changes{v1.0p}{1994/05/12}{(ASAJ) Fixed a bug with \cs{relax}
% which was
% using \cs{@gobble} before defining it.}
% \changes{v1.0q}{1994/05/13}{(ASAJ) Renamed
% \cs{DeclareProtectedCommand} to
% \cs{DeclareRobustCommand}. Removed \cs{@if@short@command}.}
% \changes{v1.0q}{1994/05/13}{(ASAJ) Replaces \cs{space} by `~' in
% \cs{csname}.}
% \changes{v1.0r}{1994/05/13}{(ASAJ) Added logging message to
% \cs{DeclareProtectedCommand}.}
% \changes{v1.0s}{1994/05/13}{(ASAJ) Added \cs{@backslashchar}.}
% \changes{v1.0s}{1994/05/13}{(ASAJ) Coded \cs{@ifdefinable} more
% efficiently.}
% \changes{v1.1a}{1994/05/16}{(ASAJ) Split from ltinit.dtx.}
% \changes{v1.1b}{1994/05/17}{(ASAJ) Removed warnings and logging to
% lterror.dtx.}
% \changes{v1.1b}{1994/05/17}{(ASAJ) Added definitions for protect.}
% \changes{v1.1c}{1994/05/17}{(ASAJ) Redid definitions for protect.}
% \changes{v1.1d}{1994/05/19}{(RmS) Added definitions for
% \cs{@namedef} and \cs{@nameuse} again.}
% \changes{v1.1e}{1994/05/20}{Changed command name from
% \cs{@checkcommand} to \cs{CheckCommand}.}
% \changes{v1.1f}{1994/05/22}{Use new warning and error cmds}
% \changes{v1.2a}{1994/10/18}{Add star-forms for all commands}
% \changes{v1.2a}{1994/10/18}{Add extra test for \cs{endgraf}}
% \changes{v1.2b}{1994/10/25}{Documentation improvements}
% \changes{v1.2c}{1994/10/30}{(CAR)\cs{@onelevel@sanitize} added}
% \changes{v1.2f}{1994/10/30}{(DPC)\cs{newwrite}'s moved to ltfiles}
% \changes{v1.0g}{1994/11/17}
% {\cs{@tempa} to \cs{reserved@a}}
% \changes{v1.0p}{1995/07/13}{Updates to documentation}
% \changes{v1.4b}{2015/02/21}
% {Removed autoload support}
% \changes{v1.5l}{2020/08/21}{Integration of new hook management interface}
%
% \section{Definitions}
%
% This section contains commands used in defining other macros.
%
% \MaybeStop{}
%
% \begin{macrocode}
%<*2ekernel>
% \end{macrocode}
%
%
% \subsection{Initex initializations}
%
% \task{???}{This section needs extension}
%
% \begin{macro}{\two@digits}
% \changes{LaTeX2e}{1993/11/23}{Macro added}
% Prefix a number less than 10 with `0'.
% \begin{macrocode}
\def\two@digits#1{\ifnum#1<10 0\fi\number#1}
% \end{macrocode}
% \end{macro}
%
% \changes{v1.2e}{1994/11/04}{Added \cs{set@display@protect} to
% \cs{typeout}. ASAJ.}
%
% \begin{macro}{\typeout}
% Display something on the terminal.
% \changes{v1.5g}{2020/05/15}{Allow \cs{par} in the argument (gh/335)}
% \begin{macrocode}
%</2ekernel>
%<*2ekernel|latexrelease>
%<latexrelease>\IncludeInRelease{2020/10/01}%
%<latexrelease> {\typeout}{Allow "par" in \typeout}%
\protected\long\def\typeout#1{\begingroup
\set@display@protect
\def\par{^^J^^J}%
\immediate\write\@unused{#1}\endgroup}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease> {\typeout}{Allow "par" in \typeout}%
%<latexrelease>
%<latexrelease>\def\typeout#1{\begingroup\set@display@protect
%<latexrelease> \immediate\write\@unused{#1}\endgroup}
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\newlinechar}
% A char to be used as new-line in output to files.
% \begin{macrocode}
\newlinechar`\^^J
% \end{macrocode}
% \end{macro}
%
% \subsection{Saved versions of \TeX{} primitives}
%
% The TeX primitive |\foo| is saved as |\@@foo|.
% The following primitives are handled in this way:
% \begin{macro}{\@@par}
% \begin{macrocode}
\let\@@par=\par
%\let\@@input=\input %%% moved earlier
%\let\@@end=\end %%%
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@hyph}
% Save original primitive definition.
% \begin{macrocode}
\let\@@hyph=\-
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@@italiccorr}
% Save the original italic correction.
% \changes{v1.0a}{1994/03/07}{Macro added}
% \begin{macrocode}
\let\@@italiccorr=\/
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@height}
% \begin{macro}{\@depth}
% \begin{macro}{\@width}
% \begin{macro}{\@minus}
% \changes{LaTeX2e}{1993/11/22}{Macro added}
% \begin{macro}{\@plus}
% \changes{LaTeX2e}{1993/11/22}{Macro added}
%
% The following definitions save token space. E.g., using
% |\@height| instead of height saves 5 tokens at the cost in time
% of one macro expansion.
% \begin{macrocode}
\def\@height{height} \def\@depth{depth} \def\@width{width}
\def\@minus{minus}
\def\@plus{plus}
% \end{macrocode}
% \begin{macro}{\hb@xt@}
% \changes{v1.2k}{1995/05/07}{Macro added}
% The next one is another 100 tokens worth.
% \begin{macrocode}
\def\hb@xt@{\hbox to}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macrocode}
\message{hacks,}
% \end{macrocode}
%
% \subsection{Command definitions}
%
% This section defines the following commands:
%
% \DescribeMacro
% {\@namedef}\marg{NAME}\\ Expands to |\def\|\marg{NAME},
% except name can contain any characters.
%
% \DescribeMacro
% {\@nameuse}\marg{NAME}\\
% Expands to |\|\marg{NAME}.
%
% \DescribeMacro
% {\@ifnextchar} X\marg{YES}\marg{NO}\\
% Expands to \meta{YES} if next character is an `X',
% and to \meta{NO} otherwise.
% (Uses |\reserved@a|--|\reserved@c|.)
% NOTE: GOBBLES ANY SPACE FOLLOWING IT.
%
% \DescribeMacro
% {\@ifstar}\marg{YES}\marg{NO}\\
% Gobbles following spaces and then tests if next the
% character is a '*'. If it is, then it gobbles the
% `*' and expands to \meta{YES}, otherwise it expands to \meta{NO}.
%
% \DescribeMacro
% {\@dblarg}\marg{CMD}\marg{ARG}\\
% Expands to |\|\marg{CMD}\oarg{ARG}\marg{ARG}. Use
% |\@dblarg\CS| when |\CS| takes arguments |[ARG1]{ARG2}|,
% where default is| ARG1| = |ARG2|.
%
% \DescribeMacro
% {\@ifundefined}\marg{NAME}\marg{YES}\marg{NO}\\
% : If \cs{NAME} is undefined then it executes \meta{YES},
% otherwise it executes \meta{NO}. More precisely,
% true if \cs{NAME} either undefined or = |\relax|.
%
% \DescribeMacro
% {\@ifdefinable}|\NAME|\marg{YES}
% Executes \meta{YES} if the user is allowed to define |\NAME|,
% otherwise it gives an error. The user can define |\NAME|
% if |\@ifundefined{NAME}| is true, '|NAME|' $\neq$ '|relax|'
% and the first three letters of '|NAME|' are not
% '|end|', and if |\endNAME| is not defined.
%
% \DescribeMacro
% \newcommand|*|\marg{\cs{FOO}}\oarg{i}\marg{TEXT}\\
% User command to define |\FOO| to be a macro with
% i arguments (i = 0 if missing) having the definition
% \meta{TEXT}. Produces an error if |\FOO| already
% defined.
%
% Normally the command is defined to be |\long| (ie it may
% take multiple paragraphs in its argument). In the
% star-form, the command is not defined as |\long| and a
% blank line in any argument to the command would generate
% an error.
%
% \DescribeMacro
% \renewcommand|*|\marg{\cs{FOO}}\oarg{i}\marg{TEXT}\\
% Same as |\newcommand|, except it checks if |\FOO| already defined.
%
% \DescribeMacro
% \newenvironment|*|\marg{FOO}\oarg{i}\marg{DEF1}\marg{DEF2}\\
% equivalent to:\\
% |\newcommand{\FOO}[i]{DEF1}| |\def{\endFOO}{DEF2}|\\
% (or the appropriate star forms).
%
% \DescribeMacro
% \renewenvironment\\ Obvious companion to |\newenvironment|.
%
% \DescribeMacro
% \@cons : See description of |\output| routine.
%
% \DescribeMacro{\@car}
% |\@car T1 T2 ... Tn\@nil| == |T1| (unexpanded)
%
% \DescribeMacro{\@cdr}
% |\@cdr T1 T2 ... Tn\@ni|l == |T2 ... Tn| (unexpanded)
%
% \DescribeMacro
% \typeout\marg{message}\\ Produces a warning message on the terminal.
%
% \DescribeMacro
% \typein\marg{message}\\
% Types message, asks the user to type in a command, then
% executes it
%
% \DescribeMacro
% \typein\oarg{\cs{CS}}\marg{MSG}\\
% Same as above, except defines |\CS| to be the input
% instead of executing it.
%
% \changes{LaTeX209}{1992/03/18}
% {(RMS) changed input channel from 0 to \cs{@inputcheck} to avoid
% conflicts with other channels allocated by \cs{newread}}
%
% \begin{macro}{\typein}
%
% \changes{v1.2k}{1995/05/08}{Use \cs{@firstofone}}
% \changes{v1.2l}{1995/05/08}{Remove unnecessary braces}
% \changes{v1.2l}{1995/05/08}{Replace \cs{def} by \cs{let}}
% \changes{v1.2m}{1995/05/24}{(DPC) New implementation}
% \changes{v1.2u}{1995/10/16}{(DPC) Use \cs{@testopt} /1911}
% \begin{macrocode}
\def\typein{%
\let\@typein\relax
\@testopt\@xtypein\@typein}
% \end{macrocode}
%
% \changes{v1.2r}{1995/10/03}
% {Add missing \cs{@typein} for /1710 (from patch file)}
% \changes{v1.4a}{2015/01/03}{use modified definition in luatex}
% \begin{macrocode}
\ifx\directlua\@undefined
% \end{macrocode}
%
% \begin{macrocode}
\def\@xtypein[#1]#2{%
\typeout{#2}%
\advance\endlinechar\@M
\read\@inputcheck to#1%
\advance\endlinechar-\@M
\@typein}%
% \end{macrocode}
%
% \begin{macrocode}
\else
% \end{macrocode}
%
% \begin{macrocode}
\def\@xtypein[#1]#2{%
\typeout{#2}%
\begingroup \endlinechar\m@ne
\read\@inputcheck to#1%
\expandafter\endgroup
\expandafter\def\expandafter#1\expandafter{#1}%
\@typein}%
% \end{macrocode}
%
% \begin{macrocode}
\fi
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@namedef}
% \begin{macrocode}
\def\@namedef#1{\expandafter\def\csname #1\endcsname}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@nameuse}
% \begin{macrocode}
\def\@nameuse#1{\csname #1\endcsname}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@cons}
% \begin{macrocode}
\def\@cons#1#2{\begingroup\let\@elt\relax\xdef#1{#1\@elt #2}\endgroup}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@car}
% \begin{macro}{\@cdr}
% \begin{macrocode}
\def\@car#1#2\@nil{#1}
\def\@cdr#1#2\@nil{#2}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@carcube}
% |\@carcube T1 ... Tn\@nil| = |T1| |T2| |T3| , $n > 3$
% \changes{v1.5k}{2020/08/19}{Made \cs{long} for \cs{NewCommandCopy}}
% \changes{v1.5o}{2020/11/25}{Added missing latexrelease entry}
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020/10/01}{\@carcube}{Make \@carcube long}%
%<*2ekernel|latexrelease>
\long\def\@carcube#1#2#3#4\@nil{#1#2#3}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{0000/00/00}{\@carcube}{Undo: Make \@carcube long}%
%<latexrelease>\def\@carcube#1#2#3#4\@nil{#1#2#3}
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
%
%
% \begin{macro}{\@onlypreamble}
% \begin{macro}{\@preamblecmds}
% This macro adds its argument to the list of commands stored in
% |\@preamblecmds| to be
% disabled after |\begin{document}|. These commands are redefined
% to generate |\@notprerr| at this point.
% \begin{macrocode}
\def\@preamblecmds{}
\def\@onlypreamble#1{%
\expandafter\gdef\expandafter\@preamblecmds\expandafter{%
\@preamblecmds\do#1}}
\@onlypreamble\@onlypreamble
\@onlypreamble\@preamblecmds
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@star@or@long}
% \changes{v1.2a}{1994/10/18}{macro added}
% Look ahead for a |*|. If present reset |\l@ngrel@x| so that
% the next definition, |#1|, will be non-long.
% \begin{macrocode}
\def\@star@or@long#1{%
\@ifstar
{\let\l@ngrel@x\relax#1}%
{\let\l@ngrel@x\long#1}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\l@ngrel@x}
% This is either |\relax| or |\long| depending on whether the |*|-form
% of a definition command is being executed.
% \begin{macrocode}
\let\l@ngrel@x\relax
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\newcommand}
% \changes{LaTeX2e}{1993/11/23}{Macro reimplemented and extended}
% User level |\newcommand|.%
% \begin{macrocode}
\def\newcommand{\@star@or@long\new@command}
% \end{macrocode}
%
% \begin{macro}{\new@command}
% \changes{v1.2u}{1995/10/16}{(DPC) Use \cs{@testopt} /1911}
% \begin{macrocode}
\def\new@command#1{%
\@testopt{\@newcommand#1}0}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@newcommand}
% \changes{LaTeX2e}{1993/11/23}{Macro added}
% \begin{macro}{\@argdef}
% \changes{LaTeX2e}{1993/11/23}{Macro added}
% \begin{macro}{\@xargdef}
% \changes{LaTeX2e}{1993/11/23}{Macro interface changed}
% \changes{v1.1g}{2004/01/23}{Use kernel version of
% \cs{@ifnextchar} (pr/3501)}
% Handling arguments for |\newcommand|.
% \begin{macrocode}
\def\@newcommand#1[#2]{%
\kernel@ifnextchar [{\@xargdef#1[#2]}%
{\@argdef#1[#2]}}
% \end{macrocode}
% Define |#1| if it is definable.
%
% Both here and in |\@xargdef| the replacement text is absorbed as
% an argument because if we are not allowed to make the definition
% we have to get rid of it completely.
% \begin{macrocode}
\long\def\@argdef#1[#2]#3{%
\@ifdefinable #1{\@yargdef#1\@ne{#2}{#3}}}
% \end{macrocode}
%
% \changes{v1.2q}{1995/10/02}
% {New implementation, using \cs{@test@opt}}
% Handle the second optional argument.
% \begin{macrocode}
\long\def\@xargdef#1[#2][#3]#4{%
\@ifdefinable#1{%
% \end{macrocode}
% Define the actual command to be:\\
% |\def\foo{\@protected@testopt\foo\\foo{default}}|\\
% where |\\foo| is a csname generated from applying |\csname| and
% |\string| to |\foo|, ie the actual name contains a backslash and
% therefore can't clash easily with existing command names.
% ``Default'' is the contents of the second optional argument of
% |(re)newcommand|.
%
% \changes{v1.2z2}{1998/03/04}
% {Unnecessary \cs{expandafter} removed: pr/2758}
% \begin{macrocode}
\expandafter\def\expandafter#1\expandafter{%
\expandafter
\@protected@testopt
\expandafter
#1%
\csname\string#1\endcsname
{#3}}%
% \end{macrocode}
% Now we define the internal macro ie |\\foo| which is supposed to
% pick up all arguments (optional and mandatory).
% \begin{macrocode}
\expandafter\@yargdef
\csname\string#1\endcsname
\tw@
{#2}%
{#4}}}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@testopt}
% \changes{v1.2q}{1995/10/02}
% {Macro added}
% \changes{v1.3a}{1999/01/07}
% {made long and brace optional arg. latex/2896}
% This macro encapsulates the most common call to |\@ifnextchar|, saving
% several tokens each time it is used in the definition of a command
% with an optional argument.
% |#1| The code to execute in the case that there is a |[| need not be
% a single token but can be any sequence of commands that `expects' to
% be followed by |[|. If this command were only used in |\newcommand|
% definitions then |#1| would be a single token and the braces could
% be omitted from |{#1}| in the definition below, saving a bit of
% memory.
% \changes{v1.1g}{2004/01/23}{Use kernel version of
% \cs{@ifnextchar} (pr/3501)}
% \begin{macrocode}
\long\def\@testopt#1#2{%
\kernel@ifnextchar[{#1}{#1[{#2}]}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@protected@testopt}
% \changes{v1.2q}{1995/10/02}
% {Macro added}
% Robust version of |\@testopt|. The extra argument (|#1|) must be a
% single token. If protection is needed the call expands to |\protect|
% applied to this token, and the 2nd and 3rd arguments are
% discarded (by |\@x@protect|). Otherwise |\@testopt| is called on
% the 2nd and 3rd arguments.
%
% This method of making commands robust avoids the need for using up
% two csnames per command, the price is the extra expansion time
% for the |\ifx| test.
% \begin{macrocode}
\def\@protected@testopt#1{%
\ifx\protect\@typeset@protect
\expandafter\@testopt
\else
\@x@protect#1%
\fi}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@yargdef}
% \begin{macro}{\@yargd@f}
% \changes{v1.3f}{1999/04/29}{New macro added}
%
% \changes{LaTeX2e}{1993/11/23}{Macro interface changed}
% \changes{LaTeX2e}{1993/11/23}{Avoid \cs{@?@?} token}
% \changes{v1.0b}{1994/03/12}{Name changed from \cs{XXX@argdef}}
% \changes{v1.3c}{1999/01/18}{New implementation DPC /2942}
% \changes{v1.3d}{1999/02/09}{catch bad argument forms by re-inserting \#3}
% \changes{v1.3f}{1999/04/29}{Full expansion and conversion needed
% for digit in new version, see pr/3013}
%
% These generate a primitive argument specification, from a
% \LaTeX\ |[|\meta{digit}|]| form; in fact \meta{digit} can be
% anything such that |\number|~\meta{digit} is single digit.
%
% Reorganised slightly so that |\renewcommand{\reserved@a}[1]{foo}|
% works. I am not sure this is worth it, as a following
% |\newcommand| would over-write the definition of |\reserved@a|.
%
% Recall that \LaTeX2.09 goes into an infinite loop with\\
% |\renewcommand[1]{\@tempa}{foo}|\\
% (DPC 6 October 93).
%
% Reorganised again (DPC 1999). Rather than make a loop to
% construct the argument spec by counting, just extract the
% required argument spec by using a delimited argument (delimited
% by the digit). This is faster and uses less tokens. The coding
% is slightly odd to preserve the old interface (using |#2| =
% |\tw@| as the flag to surround the first argument with |[]|. But
% the new method did not allow for the number of arguments |#3| not
% being given as an explicit digit; hence (further expansion of
% this argument and use of) |\number| was added later in 1999.
%
% It is not clear why these are still |\long|.
%
% \begin{macrocode}
\long \def \@yargdef #1#2#3{%
\ifx#2\tw@
\def\reserved@b##11{[####1]}%
\else
\let\reserved@b\@gobble
\fi
\expandafter
\@yargd@f \expandafter{\number #3}#1%
}
% \end{macrocode}
%
% \begin{macrocode}
\long \def \@yargd@f#1#2{%
\def \reserved@a ##1#1##2##{%
\expandafter\def\expandafter#2\reserved@b ##1#1%
}%
\l@ngrel@x \reserved@a 0##1##2##3##4##5##6##7##8##9###1%
}
% \end{macrocode}
%
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@reargdef}
% \changes{LaTeX2e}{1993/12/20}
% {Kept old version of \cs{@reargdef}, for array.sty}
% \changes{v1.0b}{1994/03/12}{New defn, in terms of \cs{@yargdef}}
% \changes{v1.2y}{1996/07/26}{third arg picked up by \cs{@yargdef}}
% \begin{macrocode}
\long\def\@reargdef#1[#2]{%
\@yargdef#1\@ne{#2}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\renewcommand}
% Check the command name is already used. If not give an error
% message. Then temporarily
% disable |\@ifdefinable| then call |\newcommand|. (Previous
% version |\let#1=\relax| but this does not work too well if |#1|
% is |\@temp|\emph{a--e}.)
% \changes{LaTeX2e}{1993/11/23}{Macro reimplemented and extended}
% \changes{v1.1f}{1994/05/02}{Removed surplus \cs{space} in error}
% \begin{macrocode}
\def\renewcommand{\@star@or@long\renew@command}
% \end{macrocode}
%
% \begin{macro}{\renew@command}
% \changes{v1.2y}{1996/07/26}{use \cs{relax} in place of empty arg}
% \changes{v1.2y}{1996/07/26}{use \cs{noexpand} instead of \cs{string}}
% \changes{v1.2z1}{1997/10/21}{Use \cs{begingroup}/\cs{endgroup} rather
% than braces for grouping, to avoid generating empty math atom.}
% \changes{v1.5e}{2018/09/26}{Always explicitly generate a space after the csname and
% not rely on \cs{noexpand} to save tokens (git/41)}
% \begin{macrocode}
\def\renew@command#1{%
\begingroup \escapechar\m@ne\xdef\@gtempa{{\string#1}}\endgroup
\expandafter\@ifundefined\@gtempa
{\@latex@error{Command \string#1 undefined}\@ehc}%
\relax
\let\@ifdefinable\@rc@ifdefinable
\new@command#1}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \changes{v1.0n}{1994/05/10}{Removed braces around \cs{@ifundefined}
% argument. ASAJ.}
% \changes{v1.0s}{1994/05/13}{Coded more efficiently, thanks to FMi.}
%
% \begin{macro}{\@ifdefinable}
% \begin{macro}{\@@ifdefinable}
% \begin{macro}{\@rc@ifdefinable}
% Test if user is allowed to define a command.
% \begin{macrocode}
\long\def\@ifdefinable #1#2{%
\edef\reserved@a{\expandafter\@gobble\string #1}%
\@ifundefined\reserved@a
{\edef\reserved@b{\expandafter\@carcube \reserved@a xxx\@nil}%
\ifx \reserved@b\@qend \@notdefinable\else
\ifx \reserved@a\@qrelax \@notdefinable\else
#2%
\fi
\fi}%
\@notdefinable}
% \end{macrocode}
% Saved definition of |\@ifdefinable|.
% \begin{macrocode}
\let\@@ifdefinable\@ifdefinable
% \end{macrocode}
% Version of |\@ifdefinable| for use with |\renewcommand|. Does
% not do the check this time, but restores the normal definition.
% \begin{macrocode}
\long\def\@rc@ifdefinable#1#2{%
\let\@ifdefinable\@@ifdefinable
#2}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\newenvironment}
% Define a new user environment.
% |#1| is the environment name. |#2#| Grabs all the tokens up to
% the first |{|. These will be any optional arguments. They are not
% parsed at this point, but are just passed to |\@newenv| which
% will eventually call |\newcommand|. Any optional arguments will
% then be parsed by |\newcommand| as it defines the command that
% executes the `begin code' of the environment.
%
% This |#2#| trick removed with version 1.2i as it fails if a |{|
% occurs in the optional argument. Now use |\@ifnextchar| directly.
% \begin{macrocode}
\def\newenvironment{\@star@or@long\new@environment}
% \end{macrocode}
%
% \begin{macro}{\new@environment}
% \changes{v1.2i}{1995/04/25}{Parse arguments slowly but safely /1507}
% \changes{v1.2u}{1995/10/16}{(DPC) Use \cs{@testopt} /1911}
% \begin{macrocode}
\def\new@environment#1{%
\@testopt{\@newenva#1}0}
% \end{macrocode}
%
% \begin{macro}{\@newenva}
% \changes{v1.1g}{2004/01/23}{Use kernel version of
% \cs{@ifnextchar} (pr/3501)}
% \begin{macrocode}
\def\@newenva#1[#2]{%
\kernel@ifnextchar [{\@newenvb#1[#2]}{\@newenv{#1}{[#2]}}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@newenvb}
% \changes{v1.3a}{1999/01/07}
% {made long and brace optional arg. latex/2896}
% \begin{macrocode}
\def\@newenvb#1[#2][#3]{\@newenv{#1}{[#2][{#3}]}}
% \end{macrocode}
% \end{macro}
%
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\renewenvironment}
% Redefine an environment.
% For |\renewenvironment| disable |\@ifdefinable| and then call
% |\newenvironment|. It is OK to |\let| the argument to |\relax|
% here as there should not be a |@temp|\ldots\ environment.
% \changes{LaTeX2e}{1993/11/23}{Macro reimplemented and extended}
% \changes{v1.1f}{1994/05/02}{Removed surplus \cs{space} in error}
% \begin{macrocode}
\def\renewenvironment{\@star@or@long\renew@environment}
% \end{macrocode}
%
% \begin{macro}{\renew@environment}
% \changes{v1.2a}{1994/10/18}{reset end command}
% \changes{v1.2y}{1996/07/26}{use \cs{relax} in place of empty arg}
% \begin{macrocode}
\def\renew@environment#1{%
\@ifundefined{#1}%
{\@latex@error{Environment #1 undefined}\@ehc
}\relax
\expandafter\let\csname#1\endcsname\relax
\expandafter\let\csname end#1\endcsname\relax
\new@environment{#1}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@newenv}
% \changes{LaTeX2e}{1993/11/23}{Macro interface changed}
% \changes{v1.2h}{1994/11/24}{Added test for \cs{endgraf}}
% The internal version of |\newenvironment|.
%
% Call |\newcommand| to define the \meta{begin-code} for the
% environment. |\def| is used for the \meta{end-code} as it does
% not take arguments. (but may contain |\par|s)
%
% Make sure that an attempt to define a `graf' or `group' environment
% fails by temporarily letting the undefined \verb=\...= (begin code) to
% the definition of \verb=\end...= and as a result we get an error if that
% has a definition.
% \begin{macrocode}
\long\def\@newenv#1#2#3#4{%
\@ifundefined{#1}%
{\expandafter\let\csname#1\expandafter\endcsname
\csname end#1\endcsname}%
\relax
\expandafter\new@command
\csname #1\endcsname#2{#3}%
\l@ngrel@x\expandafter\def\csname end#1\endcsname{#4}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\newif}
% \changes{v1.1l}{1995/05/24}{(DPC) New implementation}
% And here's a different sort of allocation:
% For example,
% |\newif\iffoo| creates |\footrue|, |\foofalse| to go with |\iffoo|.
% \begin{macrocode}
\def\newif#1{%
\count@\escapechar \escapechar\m@ne
\let#1\iffalse
\@if#1\iftrue
\@if#1\iffalse
\escapechar\count@}
% \end{macrocode}
%
% \begin{macro}{\@if}
% \begin{macrocode}
\def\@if#1#2{%
\expandafter\def\csname\expandafter\@gobbletwo\string#1%
\expandafter\@gobbletwo\string#2\endcsname
{\let#1#2}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\providecommand}
% |\providecommand| takes the same arguments as |\newcommand|, but
% discards them if |#1| is already defined, Otherwise it just acts like
% |\newcommand|. This implementation currently leaves any discarded
% definition in |\reserved@a| (and possibly |\\reserved@a|) this
% wastes a bit of space, but it will be reclaimed as soon as these
% scratch macros are redefined.
%
% \changes{LaTeX2e}{1993/11/22}{Macro added}
% \begin{macrocode}
\def\providecommand{\@star@or@long\provide@command}
% \end{macrocode}
%
% \begin{macro}{\provide@command}
% \changes{v1.2z}{1997/09/09}{Use \cs{begingroup} to avoid generating
% math ords if used in math mode. pr/2573}
% \begin{macrocode}
\def\provide@command#1{%
\begingroup
\escapechar\m@ne\xdef\@gtempa{{\string#1}}%
\endgroup
\expandafter\@ifundefined\@gtempa
{\def\reserved@a{\new@command#1}}%
{\def\reserved@a{\renew@command\reserved@a}}%
\reserved@a}%
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\CheckCommand}
% \changes{LaTeX2e}{1993/11/22}{Macro added}
% \changes{v1.1e}{1994/05/20}{Changed name from \cs{@checkcommand} to
% \cs{CheckCommand}.}
% |\CheckCommand| takes the same arguments as |\newcommand|. If
% the command already exists, with the same definition, then
% nothing happens, otherwise a warning is issued. Useful for
% checking the current state before a macro package starts
% redefining things. Currently two macros are considered to have
% the same definition if they are the same except for different
% default arguments. That is, if the old definition was:
% |\newcommand\xxx[2][a]{(#1)(#2)}| then
% |\CheckCommand\xxx[2][b]{(#1)(#2)}| would \emph{not} generate a
% warning, but, for instance |\CheckCommand\xxx[2]{(#1)(#2)}|
% would.
% \begin{macrocode}
\def\CheckCommand{\@star@or@long\check@command}
% \end{macrocode}
% |\CheckCommand| is only available in the preamble part of the
% document.
% \begin{macrocode}
\@onlypreamble\CheckCommand
% \end{macrocode}
%
% \begin{macro}{\check@command}
% \begin{macrocode}
\def\check@command#1#2#{\@check@c#1{#2}}
\@onlypreamble\check@command
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@check@c}
% \changes{v1.2i}{1995/04/25}{Make \cs{long} for latex/1346}
% |\CheckCommand| itself just grabs all the arguments we need,
% without actually looking for |[| optional argument forms. Now
% define |\reserved@a|. If |\\reserved@a| is then defined, compare it
% with the ``|\#1|' otherwise compare |\reserved@a| with |#1|.
% \begin{macrocode}
\long\def\@check@c#1#2#3{%
\expandafter\let\csname\string\reserved@a\endcsname\relax
\renew@command\reserved@a#2{#3}%
\@ifundefined{\string\reserved@a}%
{\@check@eq#1\reserved@a}%
{\expandafter\@check@eq
\csname\string#1\expandafter\endcsname
\csname\string\reserved@a\endcsname}}
\@onlypreamble\@check@c
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@check@eq}
% Complain if |#1| and |#2| are not |\ifx| equal.
% \begin{macrocode}
\def\@check@eq#1#2{%
\ifx#1#2\else
\@latex@warning@no@line
{Command \noexpand#1 has
changed.\MessageBreak
Check if current package is valid}%
\fi}
\@onlypreamble\@check@eq
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@gobble}
% \begin{macro}{\@gobbletwo}
% \begin{macro}{\@gobblethree}
% \changes{v1.5g}{2020/02/27}{Macro added}
% \begin{macro}{\@gobblefour}
% \changes{v1.2n}{1995/05/26}{(CAR) Added \cs{long}s}
% The |\@gobble| macro is used to get rid of its argument.
% \begin{macrocode}
\long\def \@gobble #1{}
\long\def \@gobbletwo #1#2{}
\long\def \@gobblethree #1#2#3{}
\long\def \@gobblefour #1#2#3#4{}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@firstofone}
% \begin{macro}{\@firstoftwo}
% \begin{macro}{\@secondoftwo}
% Some argument-grabbers.
% \begin{macrocode}
\long\def\@firstofone#1{#1}
\long\def\@firstoftwo#1#2{#1}
\long\def\@secondoftwo#1#2{#2}
% \end{macrocode}
% \begin{macro}{\@iden}
% |\@iden| is another name for |\@firstofone| for
% compatibility reasons.
% \begin{macrocode}
\let\@iden\@firstofone
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@thirdofthree}
% Another grabber now used in the encoding specific
% section.
% \changes{v1.2z3}{1998/03/20}{Macro added}
% \begin{macrocode}
\long\def\@thirdofthree#1#2#3{#3}
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@expandtwoargs}
% A macro to totally expand two arguments to another macro
% \changes{v1.5r}{2022/10/22}{Use \cs{protected@edef}.}
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2022/11/01}%
%<latexrelease> {\@expandtwoargs}{protected edef}%
%<*2ekernel|latexrelease>
\def\@expandtwoargs#1#2#3{%
\protected@edef\reserved@a{\noexpand#1{#2}{#3}}\reserved@a}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{00/00/00}%
%<latexrelease> {\@expandtwoargs}{protected edef}%
%<latexrelease>\def\@expandtwoargs#1#2#3{%
%<latexrelease>\edef\reserved@a{\noexpand#1{#2}{#3}}\reserved@a}
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@backslashchar}
% A category code 12 backslash.
% \begin{macrocode}
\edef\@backslashchar{\expandafter\@gobble\string\\}
% \end{macrocode}
% \end{macro}
%
% \changes{v1.0n}{1994/05/10}{Added \cs{DeclareProtectedCommand}}
% \changes{v1.0p}{1994/05/12}{Fixed a bug with \cs{relax } which was
% using \cs{@gobble} before defining it.}
% \changes{v1.0q}{1994/05/13}{Renamed \cs{DeclareProtectedCommand} to
% \cs{DeclareRobustCommand}. Removed \cs{@if@short@command}.
% Moved to after the definition of \cs{@gobble}.}
% \changes{v1.0r}{1994/05/13}{Added logging message to
% \cs{DeclareProtectedCommand}.}
%
% \subsection{Robust commands and protect}
%
% \changes{v1.1b}{1994/05/17}{Added the discussion of protected
% commands, defined the values that \cs{protect} should have.}
% \changes{v1.1c}{1994/05/18}{Redid the discussion and definitions, in
% line with the proposed new setting of \cs{protect} in the output
% routine.}
%
% Fragile and robust commands are one of the thornier issues in
% \LaTeX's commands. Whilst typesetting documents, \LaTeX{} makes use
% of many of \TeX's features, such as arithmetic, defining macros, and
% setting variables. However, there are (at least) three different
% occasions when these commands are not safe. These are called
% `moving arguments' by \LaTeX, and consist of:
% \begin{itemize}
% \item writing information to a file, such as indexes or tables of
% contents.
% \item writing information to the screen.
% \item inside an |\edef|, |\message|, |\mark|, or other command which
% evaluates its argument fully.
% \end{itemize}
% The method \LaTeX{} uses for making fragile commands robust is to
% precede them with |\protect|. This can have one of four possible
% values:
% \begin{itemize}
% \item |\relax|, for normal typesetting. So |\protect\foo| will
% execute |\foo|.
% \item |\string|, for writing to the screen. So |\protect\foo| will
% write |\foo|.
% \item |\noexpand|, for writing to a file. So |\protect\foo| will
% write |\foo| followed by a space.
% \item |\@unexpandable@protect|, for writing a moving argument to a
% file. So |\protect\foo| will write |\protect\foo| followed by a
% space. This value is also used inside |\edef|s, |\mark|s and
% other commands which evaluate their arguments fully.
% More precisely, whenever the content of an |\edef| or |\xdef| etc.\
% can contain arbitrary user input not under the direct control of the
% programmer, one should use |\proetected@edef| instead of |\edef|, etc.,
% so that |\protect| has a suitable definition and the user input will
% not break if it contains fragile commands.
% \end{itemize}
%
% \changes{1.1b}{1994/05/17}
% {(ASAJ) Added the \cs{@protect@...} commands.}
% \changes{1.1c}{1994/05/18}
% {(ASAJ) Renamed the commands, and removed
% one which is no longer needed.}
%
% \begin{macro}{\@unexpandable@protect}
% \changes{1.2w}{1995/12/05}{Removed \cs{unexpandable@noexpand} as never used. internal/1733}
% \begin{macrocode}
\def\@unexpandable@protect{\noexpand\protect\noexpand}
% \end{macrocode}
% \end{macro}
%
% \changes{v1.2e}{1994/11/04}{Rewrote protected short commands
% using \cs{x@protect}. ASAJ.}
%
% \begin{macro}{\DeclareRobustCommand}
% \begin{macro}{\declare@robustcommand}
% This is a package-writers command, which has the same syntax as
% |\newcommand|, but which declares a protected command. It does
% this by having\\
% |\DeclareRobustCommand\foo|\\
% define |\foo| to be
% |\protect\foo<space>|,\\
% and then use |\newcommand\foo<space>|.\\
% Since the internal command is |\foo<space>|, when it is written
% to an auxiliary file, it will appear as |\foo|.
%
% We have to be a
% bit cleverer if we're defining a short command, such as |\_|, in
% order to make sure that the auxiliary file does not include a
% space after the command, since |\_ a| and |\_a| aren't the same.
% In this case we define |\_| to be:
%\begin{verbatim}
% \x@protect\_\protect\_<space>
%\end{verbatim}
% which expands to:
%\begin{verbatim}
% \ifx\protect\@typeset@protect\else
% \@x@protect@\_
% \fi
% \protect\_<space>
%\end{verbatim}
% Then if |\protect| is |\@typeset@protect| (normally |\relax|)
% then we just perform |\_<space>|, and otherwise
% |\@x@protect@| gobbles everything up and expands to
% |\protect\_|.
%
% \emph{Note}: setting |\protect| to any value other than |\relax|
% whilst in `typesetting' mode will cause commands to go into an
% infinite loop! In particular, setting |\protect| to |\@empty| will
% cause |\_| to loop forever. It will also break lots of other
% things, such as protected |\ifmmode|s inside |\halign|s. If you
% really have to do such a thing, then please set
% |\@typeset@protect| to be |\@empty| as well. (This is what the
% code for |\patterns| does, for example.)
%
% More fun with |\expandafter| and |\csname|.
% \begin{macrocode}
\def\DeclareRobustCommand{\@star@or@long\declare@robustcommand}
% \end{macrocode}
%
% \begin{macrocode}
\def\declare@robustcommand#1{%
\ifx#1\@undefined\else\ifx#1\relax\else
\@latex@info{Redefining \string#1}%
\fi\fi
\edef\reserved@a{\string#1}%
\def\reserved@b{#1}%
\edef\reserved@b{\expandafter\strip@prefix\meaning\reserved@b}%
\edef#1{%
\ifx\reserved@a\reserved@b
\noexpand\x@protect
\noexpand#1%
\fi
\noexpand\protect
\expandafter\noexpand\csname
\expandafter\@gobble\string#1 \endcsname
}%
\let\@ifdefinable\@rc@ifdefinable
\expandafter\new@command\csname
\expandafter\@gobble\string#1 \endcsname
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@x@protect}
% \begin{macro}{\x@protect}
%
% \begin{macrocode}
\def\x@protect#1{%
\ifx\protect\@typeset@protect\else
\@x@protect#1%
\fi
}
\def\@x@protect#1\fi#2#3{%
\fi\protect#1%
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@typeset@protect}
% We set \cs{@typeset@protect} to \cs{relax} rather than \cs{@empty}
% to make sure that the protection mechanism stops the look-ahead
% and expansion performed at the start of \cs{halign} cells.
% \begin{macrocode}
\let\@typeset@protect\relax
% \end{macrocode}
% \end{macro}
%
% \changes{v1.2e}{1994/11/04}{Added commands for setting and restoring
% \cs{protect}. ASAJ.}
%
% \begin{macro}{\set@display@protect}
% \begin{macro}{\set@typeset@protect}
% These macros set |\protect| appropriately for typesetting or
% displaying.
% \changes{v1.2o}{1995/07/03}{Use \cs{@typeset@protect} for init}
% \begin{macrocode}
\def\set@display@protect{\let\protect\string}
\def\set@typeset@protect{\let\protect\@typeset@protect}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\protected@edef}
% \begin{macro}{\protected@xdef}
% \begin{macro}{\unrestored@protected@xdef}
% \begin{macro}{\restore@protect}
% The commands |\protected@edef| and |\protected@xdef| perform
% `safe' |\edef|s and |\xdef|s, saving and restoring |\protect|
% appropriately. For cases where restoring |\protect| doesn't
% matter, there's an `unsafe' |\unrestored@protected@xdef|, useful
% if you know what you're doing!
% \begin{macrocode}
\def\protected@edef{%
\let\@@protect\protect
\let\protect\@unexpandable@protect
\afterassignment\restore@protect
\edef
}
\def\protected@xdef{%
\let\@@protect\protect
\let\protect\@unexpandable@protect
\afterassignment\restore@protect
\xdef
}
\def\unrestored@protected@xdef{%
\let\protect\@unexpandable@protect
\xdef
}
\def\restore@protect{\let\protect\@@protect}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\protect}
% The normal meaning of |\protect|
% \changes{v1.2j}{1995/04/29}{Init \cs{protect} here}
% \begin{macrocode}
\set@typeset@protect
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\MakeRobust}
% \changes{v1.4a}{2015/01/08}{Added macro}
% \changes{v1.5f}{2019/08/27}{Make the assignments global as we may
% need to apply them inside a group}
% \changes{v1.5m}{2020/08/21}{Make \cs{MakeRobust} produce the same
% command structure as \cs{DeclareRobustCommand}}
%
% This macro makes an existing fragile macro robust, but only if it
% hasn't been robust in the past, i.e., it checks for the existence
% of the macro
% \verb*=\<name> = and if that exists it assumes that
% \verb=\<name>= is already robust. In that case either undefine
% the inner macro first or use \cs{DeclareRobustCommand} to
% define it in a robust way directly. We could probably test the
% top-level definition to have the right kind of structure, but
% this is somewhat problematical as we then have to distinguish
% between \cs{long} macros and others and also take into account
% that sometimes the top-level is deliberately done manually (like
% with \cs{begin}).
%
% The macro firstly checks if the control sequence in question exists
% at all.
% \changes{v1.5p}{2021/05/26}{Normalize error message in \cs{MakeRobust}}
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020/10/01}{\MakeRobust}{\MakeRobust}%
%<*2ekernel|latexrelease>
\def\MakeRobust#1{%
\count@=\escapechar
\escapechar=`\\
\@ifundefined{\expandafter\@gobble\string#1}{%
\@latex@error{Command `\string#1' undefined.%
\MessageBreak There is nothing here to make robust}%
\@eha
}%
% \end{macrocode}
% Then we check if the macro is already robust. We do this by testing
% if the internal name for a robust macro is defined, namely
% \verb*=\foo =. If it is already defined do nothing, otherwise set
% \verb*=\foo = equal to \verb*=\foo= and redefine \verb*=\foo= so
% that it acts like a macro defined with \verb=\DeclareRobustCommand=.
% We use \cs{@kernel@rename@newcommand} to copy \verb*=\foo= over to
% \verb*=\foo =, including a possible default optional argument.
% \begin{macrocode}
{%
\@ifundefined{\expandafter\@gobble\string#1\space}%
{%
\expandafter\@kernel@rename@newcommand
\csname\expandafter\@gobble\string#1\space\endcsname
#1%
\edef\reserved@a{\string#1}%
\def\reserved@b{#1}%
\edef\reserved@b{\expandafter\strip@prefix\meaning\reserved@b}%
\xdef#1{%
\ifx\reserved@a\reserved@b
\noexpand\x@protect\noexpand#1%
\fi
\noexpand\protect\expandafter\noexpand
\csname\expandafter\@gobble\string#1\space\endcsname}%
}%
{\@latex@info{Command `\string#1' is already robust}}%
}%
\escapechar=\count@
}%
% \end{macrocode}
%
% \begin{macro}{\@kernel@rename@newcommand}
% This macro renames a command, possibly with an optional argument (defined
% with \cs{newcommand}) from |#2| to |#1|, by renaming the internal macro
% \verb=\\#2= to \verb=\\#1= and defining \verb=\#1= appropriately, then
% undefining \verb=\#2= and \verb=\\#2=. The \cs{afterassignment} trick is
% to make both definitions in \cs{@copy@newcommand} global (which are local
% by default).
%
% In case the macro was defined with \cs{newcommand} and an optional
% argument, to replicate exactly the behaviour of \cs{DeclareRobustCommand}
% we have to move also the internal \verb*=\\foo= to \verb*=\\foo =. In that
% case, \verb=#1= will be a parameterless macro (\cs{robust@command@chk@safe}
% checks that), and \cs{@if@newcommand} will return true (both defined below
% in this file). If so, we can use \cs{@copy@newcommand} rather than plain
% \cs{let} to copy the command over. \cs{@kernel@rename@newcommand} does
% this test and carries out the renaming.
% \begin{macrocode}
\def\@kernel@rename@newcommand#1#2{%
\robust@command@chk@safe#2%
{\@if@newcommand#2%
{\afterassignment\global
\global\@copy@newcommand#1#2%
\global\let#2\@undefined
\global\expandafter\let\csname\string#2\endcsname\@undefined}%
{\global\let#1=#2}}%
{\global\let#1=#2}}
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{2019/10/01}{\MakeRobust}{\MakeRobust}%
%<latexrelease>\def\MakeRobust#1{%
%<latexrelease> \@ifundefined{\expandafter\@gobble\string#1}{%
%<latexrelease> \@latex@error{The control sequence `\string#1' is undefined!%
%<latexrelease> \MessageBreak There is nothing here to make robust}%
%<latexrelease> \@eha
%<latexrelease> }%
%<latexrelease> {%
%<latexrelease> \@ifundefined{\expandafter\@gobble\string#1\space}%
%<latexrelease> {%
%<latexrelease> \global\expandafter\let\csname
%<latexrelease> \expandafter\@gobble\string#1\space\endcsname=#1%
%<latexrelease> \edef\reserved@a{\string#1}%
%<latexrelease> \def\reserved@b{#1}%
%<latexrelease> \edef\reserved@b{\expandafter\strip@prefix\meaning\reserved@b}%
%<latexrelease> \xdef#1{%
%<latexrelease> \ifx\reserved@a\reserved@b
%<latexrelease> \noexpand\x@protect\noexpand#1%
%<latexrelease> \fi
%<latexrelease> \noexpand\protect\expandafter\noexpand
%<latexrelease> \csname\expandafter\@gobble\string#1\space\endcsname}%
%<latexrelease> }%
%<latexrelease> {\@latex@info{The control sequence `\string#1' is already robust}}%
%<latexrelease> }%
%<latexrelease>}%
%<latexrelease>\let\@kernel@rename@newcommand\@undefined
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{2015/01/01}{\MakeRobust}{\MakeRobust}%
%<latexrelease>\def\MakeRobust#1{%
%<latexrelease> \@ifundefined{\expandafter\@gobble\string#1}{%
%<latexrelease> \@latex@error{The control sequence `\string#1' is undefined!%
%<latexrelease> \MessageBreak There is nothing here to make robust}%
%<latexrelease> \@eha
%<latexrelease> }%
%<latexrelease> {%
%<latexrelease> \@ifundefined{\expandafter\@gobble\string#1\space}%
%<latexrelease> {%
%<latexrelease> \expandafter\let\csname
%<latexrelease> \expandafter\@gobble\string#1\space\endcsname=#1%
%<latexrelease> \edef\reserved@a{\string#1}%
%<latexrelease> \def\reserved@b{#1}%
%<latexrelease> \edef\reserved@b{\expandafter\strip@prefix\meaning\reserved@b}%
%<latexrelease> \edef#1{%
%<latexrelease> \ifx\reserved@a\reserved@b
%<latexrelease> \noexpand\x@protect\noexpand#1%
%<latexrelease> \fi
%<latexrelease> \noexpand\protect\expandafter\noexpand
%<latexrelease> \csname\expandafter\@gobble\string#1\space\endcsname}%
%<latexrelease> }%
%<latexrelease> {\@latex@info{The control sequence `\string#1' is already robust}}%
%<latexrelease> }%
%<latexrelease>}%
%<latexrelease>\let\@kernel@rename@newcommand\@undefined
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{0000/00/00}{\MakeRobust}{\MakeRobust}%
%<latexrelease>\let\MakeRobust\@undefined
%<latexrelease>\let\@kernel@rename@newcommand\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\kernel@make@fragile}
% The opposite of |\MakeRobust| except that it doesn't do many
% checks as it is internal to the kernel. Why does one want such a
% thing?
% Only for compatibility reasons if \texttt{latexrelease} requests
% a rollback of the kernel. For this reason we pretend that this
% command existed in all earlier versions of \LaTeX{} i.e., we are
% not rolling it back since we need it precisely then. But we have
% to get it into the \texttt{latexrelease} file so that a roll
% forward is possible too.
% \begin{macrocode}
%</2ekernel>
%<*2ekernel|latexrelease>
%<latexrelease>\IncludeInRelease{2020/10/01}%
%<latexrelease> {\kernel@make@fragile}{Undo robustness}%
\def\kernel@make@fragile#1{%
\@ifundefined{\expandafter\@gobble\string#1\space}%
% \end{macrocode}
% If not robust do nothing.
% \begin{macrocode}
{}%
% \end{macrocode}
% Otherwise copy \verb*=\foo = back to \verb=\foo=.
% Then use \cs{@kernel@rename@newcommand} to check and copy
% \verb*=\\foo = back to \verb*=\\foo= in case the command has an optional
% argument. If so, also undefine \verb*=\\foo =, and at the end undefine
% \verb*=\foo =.
% \begin{macrocode}
{%
\global\expandafter\let\expandafter #1\csname
\expandafter\@gobble\string#1\space\endcsname
\expandafter\@kernel@rename@newcommand
\csname\expandafter\@gobble\string#1\expandafter\endcsname
\csname\expandafter\@gobble\string#1\space\endcsname
\global\expandafter\let\csname
\expandafter\@gobble\string#1\space\endcsname\@undefined
}%
}
% \end{macrocode}
%
% \begin{macrocode}
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease> {\kernel@make@fragile}{Undo robustness}%
%<latexrelease>\def\kernel@make@fragile#1{%
%<latexrelease> \@ifundefined{\expandafter\@gobble\string#1\space}%
%<latexrelease> {}%
%<latexrelease> {%
%<latexrelease> \global\expandafter\let\expandafter #1\csname
%<latexrelease> \expandafter\@gobble\string#1\space\endcsname
%<latexrelease> \global\expandafter\let\csname
%<latexrelease> \expandafter\@gobble\string#1\space\endcsname\@undefined
%<latexrelease> }%
%<latexrelease>}
%<latexrelease>\EndIncludeInRelease
%</2ekernel|latexrelease>
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
%
% \subsection{Acting on robust commands}
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020-10-01}{\robust@command@act}
%<latexrelease> {Add \robust@command@act}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% With most document level commands being robust now there is more of a
% requirement to have a standard way of aliasing (or copying) a command to a
% new name, for example to save an original definition before changing a
% command. \cs{DeclareCommandCopy} is analogous to \TeX's \cs{let}, except
% that it copes with the different types of robust commands defined by
% \LaTeX's mechanisms.
%
% A couple of ``types of robustness'' are defined by the \LaTeXe{} kernel,
% namely robust commands defined with \cs{DeclareRobustCommand} and commands
% with optional arguments defined with \cs{newcommand}. However there are
% other types of robust commands that are frequently used, which are not
% defined in the \LaTeXe{} kernel, like commands defined with
% \textsf{xparse}'s \cs{NewDocumentCommand} and \textsf{etoolbox}'s
% \cs{newrobustcmd}.
%
% In this section we will define a generic extensible machinery to act on
% robust commands. This code will then be used to test if a command is
% robust, considered the different types of robustness, and then either copy
% that definition, if \cs{DeclareCommandCopy} (or similar) is used, or show
% the definition of the command, if \cs{ShowCommand} is used.
%
% \begin{macro}{\robust@command@act}
% \changes{v1.5k}{2020/08/19}{Made \cs{robust@command@act}
% (was \cs{declare@command@copy}) more generic}
%
% The looping machinery is generic and knows nothing about what is to be done
% for each case. The syntax of the main macro \cs{robust@command@act} is:
% \begin{quote}
% |\robust@command@act|\meta{action-list}\meta{robust-cmd}\\
% \meta{fallback-action}\meta{act-arg}
% \end{quote}
% \meta{action-list} is a token list of the form:
% \begin{quote}
% |{|\meta{if-type-1} \meta{act-type-1}|}|\\
% |{|\meta{if-type-2} \meta{act-type-2}|}|\\
% \ldots
% \end{quote}
% \cs{robust@command@act} will iterate over the \meta{action-list}, evaluating
% each \meta{if-type-$n$} \meta{robust-cmd} |{|\meta{true}|}{|\meta{false}|}|.
% If the \meta{if-type-$n$} conditional returns \meta{true}, then
% \meta{act-type-$n$}\meta{act-arg} is executed, and the loop ends. If the
% conditional returns \meta{false}, then \meta{if-type-$n+1$} is executed in
% the same way, until either one of the conditionals return \meta{true}, or
% the end of the \meta{action-list} is reached. If the end is reached, then
% \meta{fallback-action}\meta{act-arg} is executed before
% \cs{robust@command@act} exits.
%
% \cs{robust@command@act} will start by using \cs{robust@command@act@chk@args}
% to check if the \meta{robust-cmd} (|#2|) is a parameterless (possibly
% \cs{protected}) macro. If it is not, the command is not a robust command:
% these always start with a parameterless user-level macro; in that case,
% \cs{robust@command@act@end} is used to short-circuit the process and do the
% \meta{fallback-action} (|#3|). This first test is necessary because later
% on we need to be able to expand the \meta{robust-cmd} without the risk of it
% Breaking Badly, and as a bonus, this speeds up the process in case we used
% \cs{NewCommandCopy} in a ``normal'' macro.
% \begin{macrocode}
\long\def\robust@command@act#1#2#3#4{%
\robust@command@chk@safe#2%
{\expandafter\robust@command@act@loop
\expandafter#2%
#1{\@nnil\@nnil}%
\robust@command@act@end}%
{\robust@command@act@end}%
{#3}{#4}}%
% \end{macrocode}
%
% \begin{macro}{\robust@command@act@loop}
% \begin{macro}{\robust@command@act@loop@aux}
% \begin{macro}{\robust@command@act@do}
% If \cs{robust@command@act@chk@args} branched to false, then
% \cs{robust@command@act@loop} will loop over the list of items in the
% \meta{action-list} (|#1|), and process each item as described earlier.
% If the \meta{if-type-$n$} command expands to \meta{true} then
% \cs{robust@command@act@do} is used to execute \meta{act-type-$n$} on the
% \meta{act-arg}, otherwise the loop resumes with the next item.
% \begin{macrocode}
\long\def\robust@command@act@loop#1#2{\robust@command@act@loop@aux#1#2}
\long\def\robust@command@act@loop@aux#1#2#3{%
\ifx\@nnil#2%
\else
#2{#1}%
{\robust@command@act@do{#3}}%
{\expandafter\robust@command@act@loop\expandafter#1}%
\fi}
\long\def\robust@command@act@do#1%
\fi#2%
\robust@command@act@end#3#4{%
\fi
#1#4}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\robust@command@act@end}
% If the end is reached and no action was taken, then do
% \meta{fallback-action}\meta{act-arg}.
% \begin{macrocode}
\long\def\robust@command@act@end#1#2{#1#2}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\robust@command@chk@safe}
% \begin{macro}{\robust@command@act@chk@args}
% \begin{macrocode}
\long\def\robust@command@chk@safe#1{%
\begingroup
\escapechar=`\\
\expandafter\endgroup\expandafter
\robust@command@act@chk@args\meaning#1:->\@nil}
\def\robust@command@act@chk@args#1:->#2\@nil{%
\@expl@str@if@eq@@nnTF{#1}{macro}%
{\@firstoftwo}%
{\@expl@str@if@eq@@nnTF{#1}{\protected macro}%
{\@firstoftwo}%
{\@secondoftwo}}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\robust@command@act}
%<latexrelease> {Add \robust@command@act}%
%<latexrelease>\let\robust@command@act\@undefined
%<latexrelease>\let\robust@command@act@loop\@undefined
%<latexrelease>\let\robust@command@act@loop@aux\@undefined
%<latexrelease>\let\robust@command@act@do\@undefined
%<latexrelease>\let\robust@command@act@end\@undefined
%<latexrelease>\let\robust@command@chk@safe\@undefined
%<latexrelease>\let\robust@command@act@chk@args\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
%
% \end{macro}
%
%
% \subsubsection{Copying robust commands}
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020-10-01}{\DeclareCommandCopy}
%<latexrelease> {Add \NewCommandCopy, \RenewCommandCopy, and \DeclareCommandCopy}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% \begin{macro}{\NewCommandCopy}
% \begin{macro}{\RenewCommandCopy}
% \begin{macro}{\DeclareCommandCopy}
% \changes{v1.5j}{2020/05/09}{Added \cs{DeclareCommandCopy} (gh/239)}
%
% \cs{NewCommandCopy} starts by checking if \verb=#1= is already defined, and
% raises an error if so, otherwise the definition is carried out.
% \cs{RenewCommandCopy} does (almost) the opposite. If the command is
% \emph{not} defined, then an error is raised. But the definition is carried
% out anyhow, so the behaviour is consistent with \cs{renewcommand}.
%
% A \cs{ProvideCommandCopy} isn't defined because it's not reasonably useful.
% \verb=\provide...= commands mean ``define this if there's no other
% definition'', but copying a command (usually) implies that the command being
% copied is defined, so \cs{ProvideCommandCopy} doesn't make a lot of sense.
% But more importantly, the most common use case of copying a command is to
% redefine it later, while preserving the old definition, as in:
% \begin{verbatim}
% \ProvideCommandCopy \A \B
% \renewcommand \B { ... \A ... }
% \end{verbatim}
% then, if \verb=\A= is already defined the first line is skipped, an in this
% case \verb=\B= won't work as expected.
%
% The three versions call the internal \cs{declare@commandcopy} with the
% proper action. \cs{@firstofone} will carry out the copy. The only case
% when the copy is not made is the \meta{false} case for \cs{NewCommandCopy},
% in which the command already exists and the definition is aborted.
% \begin{macrocode}
\def\NewCommandCopy{%
\declare@commandcopy
{\@firstofone}%
{\@firstoftwo\@notdefinable}}
\def\RenewCommandCopy{%
\declare@commandcopy
{\@latex@error{Command \@backslashchar\reserved@a\space undefined}\@ehc
\@firstofone}%
{\@firstofone}}
\def\DeclareCommandCopy{%
\declare@commandcopy
{\@firstofone}%
{\@firstofone}}
% \end{macrocode}
%
% \begin{macro}{\declare@commandcopy}
% \begin{macro}{\declare@commandcopy@do}
% Start by checking if the command is already defined. The proper action is
% taken by each specific command above. If all's good, then
% \cs{robust@command@act} is called with the proper arguments as described
% earlier, with \cs{@declarecommandcopylisthook} as the \meta{action-list} and
% \cs{declare@commandcopy@let} as the \meta{fallback-action}.
% \begin{macrocode}
\long\def\declare@commandcopy#1#2#3#4{%
\edef\reserved@a{\@expl@cs@to@str@@N#3}%
\@ifundefined\reserved@a{#1}{#2}%
{\declare@commandcopy@do{#3}{#4}}}
\long\def\declare@commandcopy@do#1#2{%
\robust@command@act
\@declarecommandcopylisthook#2%
\declare@commandcopy@let{#1#2}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@declarecommandcopylisthook}
% The initial definition of \cs{@declarecommandcopylisthook} contains the
% tests for the two types of robust command in the kernel.
% \begin{macrocode}
\def\@declarecommandcopylisthook{%
{\@if@DeclareRobustCommand \@copy@DeclareRobustCommand}%
{\@if@newcommand \@copy@newcommand}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\declare@commandcopy@let}
% The initial definition of \cs{@declarecommandcopylisthook} contains the
% tests for the two types of robust command in the kernel.
% \begin{macrocode}
\long\def\declare@commandcopy@let#1#2{\let#1=#2\relax}
% \end{macrocode}
% \end{macro}
%
% Now the rollback code.
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\DeclareCommandCopy}
%<latexrelease> {Undefine \NewCommandCopy, \RenewCommandCopy, and \DeclareCommandCopy}%
%<latexrelease>\let\NewCommandCopy\@undefined
%<latexrelease>\let\RenewCommandCopy\@undefined
%<latexrelease>\let\DeclareCommandCopy\@undefined
%<latexrelease>\let\declare@commandcopy\@undefined
%<latexrelease>\let\@declarecommandcopylisthook\@undefined
%<latexrelease>\let\declare@commandcopy@let\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2023-06-01}{\DeclareEnvironmentCopy}
%<latexrelease> {Add \NewEnvironmentCopy, \RenewEnvironmentCopy, and \DeclareEnvironmentCopy}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% \begin{macro}{\NewEnvironmentCopy}
% \begin{macro}{\RenewEnvironmentCopy}
% \begin{macro}{\DeclareEnvironmentCopy}
% If \verb=\#1= or \verb=\end#1= already exist one gets an error
% message talking about the problematical command (not the
% environment).
% The remainder of the \LaTeX{} run is probably badly
% broken and it is unlikely that continuing it gives
% reasonable results.
% \changes{v1.5s}{2022/11/24}{Add \cs{NewEnvironmentCopy},
% \cs{RenewEnvironmentCopy}, and \cs{DeclareEnvironmentCopy} (gh/963)}
% \begin{macrocode}
\def\NewEnvironmentCopy{%
\declare@environmentcopy
{\@firstofone}%
{\@firstoftwo\@notdefinable}}
\def\RenewEnvironmentCopy{%
\declare@environmentcopy
{\@latex@error{Environment \reserved@a\space undefined}\@ehc
\@firstofone}%
{\@firstofone}}
\def\DeclareEnvironmentCopy{%
\declare@environmentcopy
{\@firstofone}%
{\@firstofone}}
\long\def\declare@environmentcopy#1#2#3#4{%
\edef\reserved@a{\@ifundefined{#3}{end#3}{#3}}%
\@ifundefined\reserved@a
{\def\reserved@a{#3}#1}%
{\def\reserved@a{#3}#2}%
{\ExpandArgs{cc}\declare@commandcopy@do{#3}{#4}%
\ExpandArgs{cc}\declare@commandcopy@do{end#3}{end#4}}}
% \end{macrocode}
%
% Now the rollback code.
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\DeclareEnvironmentCopy}
%<latexrelease> {Undefine \NewEnvironmentCopy, \RenewEnvironmentCopy, and \DeclareEnvironmentCopy}%
%<latexrelease>\let\NewEnvironmentCopy\@undefined
%<latexrelease>\let\RenewEnvironmentCopy\@undefined
%<latexrelease>\let\DeclareEnvironmentCopy\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \subsubsection{Showing robust commands}
%
% \begin{macro}{\ShowCommand}
% \changes{v1.5k}{2020/08/19}{Added \cs{ShowCommand} (gh/373)}
%
% Most of the machinery defined for \cs{NewCommandCopy} can be used to show
% the definition of a robust command, in a similar fashion to \texttt{texdef}.
% The difference is that after the command's is detected to has a given type
% of robustness, rather than making a copy, we use a separate routine to show
% its definition.
%
% With all the machinery in place, \cs{ShowCommand} itself is quite simple:
% use \cs{robust@command@act} to iterate through the \cs{@showcommandlisthook}
% list, and if nothing is found, fallback to \cs{show}.
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020-10-01}{\ShowCommand}%
%<latexrelease> {Add \ShowCommand}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% \begin{macrocode}
\long\def\ShowCommand#1{%
\robust@command@act
\@showcommandlisthook#1%
\show#1}
% \end{macrocode}
%
% \begin{macro}{\@showcommandlisthook}
% The initial definition of \cs{@showcommandlisthook} contains the same tests
% as used for copying, but \cs{@show@...} commands instead of \cs{@copy@...}.
% Same as before, it is initialized to cope with \cs{DeclareRobustCommand} and
% \cs{newcommand} with optional arguments.
% \begin{macrocode}
\def\@showcommandlisthook{%
{\@if@DeclareRobustCommand \@show@DeclareRobustCommand}%
{\@if@newcommand \@show@newcommand}}
% \end{macrocode}
% \end{macro}
%
% Now the rollback code.
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\ShowCommand}
%<latexrelease> {Undefine \ShowCommand}%
%<latexrelease>\let\ShowCommand\@undefined
%<latexrelease>\let\@showcommandlisthook\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020-10-01}{\@if@DeclareRobustCommand}
%<latexrelease> {Add \@if@DeclareRobustCommand, \@if@newcommand,
%<latexrelease> \@copy@DeclareRobustCommand, \@copy@newcommand,
%<latexrelease> \@show@DeclareRobustCommand, \@show@newcommand}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% \subsubsection{Commands defined with \cs{DeclareRobustCommand}}
%
% \begin{macro}{\@if@DeclareRobustCommand}
% \changes{v1.5j}{2020/05/09}{Added \cs{DeclareCommandCopy} (gh/239)}
%
% Now that we provided a generic way to copy one macro to another, we need to
% define a way to check if a command is one of \LaTeXe's robust types. These
% tests are heavily based on Heiko's \cs{LetLtxMacro}, but chopped into
% separate macros.
%
% \cs{@if@DeclareRobustCommand} checks if a command \verb=\cmd= was defined by
% \cs{DeclareRobustCommand}. The test returns true if the expansion of
% \verb=\cmd= is exactly \verb*=\protect\cmd =.
%
% \begin{macrocode}
\long\def\@if@DeclareRobustCommand#1{%
\begingroup
\escapechar=`\\
\edef\reserved@a{\string#1}%
\edef\reserved@b{\detokenize{#1}}%
\xdef\@gtempa{%
\ifx\reserved@a\reserved@b
\noexpand\x@protect
\noexpand#1%
\fi
\noexpand\protect
\expandafter\noexpand\csname\@expl@cs@to@str@@N#1 \endcsname}%
\endgroup
\ifx\@gtempa#1\relax
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi}
% \end{macrocode}
%
% \begin{macro}{\@copy@DeclareRobustCommand}
% \begin{macro}{\copy@kernel@robust@command}
% If a command was defined by \cs{DeclareRobustCommand} (that is,
% \cs{@if@DeclareRobustCommand} returns true), then to make a copy of \verb=\cmd=
% into \verb=\foo= we define the latter such that it expands to
% \verb*=\protect\foo =, then make \verb*=\foo = equal to \verb*=\cmd =.
%
% There is one detail we need to take care of: if a command was defined with
% \cs{DeclareRobustCommand} it may still have an optional argument, in which
% case there is one more macro layer before the actual definition of the
% command. We use \cs{@if@newcommand} to check that and
% \cs{@copy@newcommand} to do the copying.
% \begin{macrocode}
\long\def\@copy@DeclareRobustCommand#1#2{%
\begingroup
\escapechar=`\\
\edef\reserved@a{\string#1}%
\edef\reserved@b{\detokenize{#1}}%
\edef\reserved@a{%
\endgroup
\def\noexpand#1{%
\ifx\reserved@a\reserved@b
\noexpand\x@protect
\noexpand#1%
\fi
\noexpand\protect
\expandafter\noexpand\csname\@expl@cs@to@str@@N#1 \endcsname}%
\noexpand\copy@kernel@robust@command
\expandafter\noexpand\csname\@expl@cs@to@str@@N#1 \endcsname
\expandafter\noexpand\csname\@expl@cs@to@str@@N#2 \endcsname}%
\reserved@a}
\long\def\copy@kernel@robust@command#1#2{%
\robust@command@chk@safe#2%
{\@if@newcommand#2%
{\@copy@newcommand}%
{\declare@commandcopy@let}}
{\declare@commandcopy@let}%
#1#2}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@show@DeclareRobustCommand}
% \begin{macro}{\show@kernel@robust@command}
% \begin{macro}{\@show@macro}
% Showing the command is pretty simple. This command prints the top-level
% expansion as \TeX's \cs{show} would, but with |robust macro:| rather than
% just |macro:|, then a blank line and then \cs{show} the inner command.
% For a macro defined with, say, |\DeclareRobustCommand\foo[1]{bar}|, it will
% print:
% \begin{verbatim}
% > \foo=robust macro:
% ->\protect \foo .
%
% > \foo =\long macro:
% #1->bar.
% \end{verbatim}
% If the inner command is defined with an optional argument, then
% \cs{@show@newcommand} is also used.
%
% The value of \cs{escapechar} is deliberately not enforced, so
% \cs{ShowCommand} behaves more like \cs{show}.
% \begin{macrocode}
\long\def\@show@DeclareRobustCommand#1{%
\typeout{> \string#1=robust macro:}%
\typeout{->\@expl@cs@replacement@spec@@N#1.^^J}%
\expandafter\show@kernel@robust@command
\csname\@expl@cs@to@str@@N#1 \endcsname}
\long\def\show@kernel@robust@command#1{%
\robust@command@chk@safe#1%
{\@if@newcommand#1%
{\@show@newcommand}%
{\@show@macro}}%
{\@show@macro}%
#1}
\let\@show@macro\show
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \end{macro}
%
% \subsubsection{Commands defined with \cs{newcommand} (with optional argument)}
%
% \begin{macro}{\@if@newcommand}
% A command \verb=\cmd= (or \verb*=\cmd =, if it was defined with
% \cs{DeclareRobustCommand}) with an optional argument will expand to
% \verb*=\@protected@testopt\cmd\\cmd{<opt>}=. To check that we look at the
% first three tokens in the expansion of \verb=\cmd=, and return true or false
% accordingly.
%
% This test \emph{requires} that the command be a parameterless macro,
% otherwise it will not work (and probably break). This is ensured with
% \cs{robust@command@chk@safe} before calling \cs{@if@newcommand}.
% \begin{macrocode}
\long\def\@if@newcommand#1{%
\edef\reserved@a{%
\noexpand\@protected@testopt
\noexpand#1%
\expandafter\noexpand\csname\@backslashchar\@expl@cs@to@str@@N#1\endcsname}%
\edef\reserved@b{%
\unexpanded\expandafter\expandafter\expandafter
{\expandafter\@carcube#1{}{}{}\@nil}}%
\ifx\reserved@a\reserved@b
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi}
% \end{macrocode}
%
% \begin{macro}{\@copy@newcommand}
% Then, if a command \verb=\cmd= takes an optional argument, we copy it to
% \verb=\foo= by defining the latter to expand to
% \verb=\@protected@testopt\foo\\foo{<opt>}=.
% \begin{macrocode}
\long\def\@copy@newcommand#1#2{%
\edef#1{\noexpand\@protected@testopt
\noexpand#1%
\expandafter\noexpand\csname\@backslashchar\@expl@cs@to@str@@N#1\endcsname
\unexpanded\expandafter\expandafter\expandafter
{\expandafter\@gobblethree#2}}%
\expandafter
\let\csname\@backslashchar\@expl@cs@to@str@@N#1\expandafter\endcsname
\csname\@backslashchar\@expl@cs@to@str@@N#2\endcsname}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@show@newcommand}
% \begin{macro}{\@show@newcommand@aux}
% A command being \cs{show}n here is guaranteed to have an optional argument.
% Start by showing the top-level expansion of the command (using \cs{typeout}
% to avoid TeX asking for interaction and extra context lines), then call
% \cs{@show@newcommand@aux} with the internal command, which contains the
% actual definition, and with the expansion of the command to extract the
% default value of the optional argument.
% \begin{macrocode}
\long\def\@show@newcommand#1{%
\typeout{> \string#1=robust macro:}%
\typeout{->\@expl@cs@replacement@spec@@N#1.^^J}%
\expandafter\@show@newcommand@aux
\csname\@backslashchar\@expl@cs@to@str@@N#1\expandafter\endcsname
\expandafter{#1}\@show@tokens}
% \end{macrocode}
%
% For a macro defined with, say, |\newcommand\foo[1][opt]{bar}|, it will
% print:
% \begin{verbatim}
% > \foo=robust macro:
% ->\@protected@testopt \foo \\foo {opt}.
%
% > \\foo=\long macro:
% > default #1=opt.
% [#1]->bar.
% \end{verbatim}
% If the command was defined with \cs{DeclareRobustCommand}, then another pair
% of lines show the top-level expansion \verb*|\protect \foo |.
% \begin{macrocode}
\long\def\@show@newcommand@aux#1#2#3{%
\typeout{> \string#1=\@expl@cs@prefix@spec@@N#1macro:}%
#3{default \string##1=\expandafter\detokenize\@gobblethree#2.^^J%
\@expl@cs@argument@spec@@N#1->\@expl@cs@replacement@spec@@N#1}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@show@tokens}
% This macro prints the contents of the token list (macro) |#1| using
% \cs{showtokens}. The \cs{expandafter} gymnastics ensures that
% \cs{showtokens} itself, and the internals of this macro aren't
% showed in the context lines.
% \begin{macrocode}
\long\def\@show@tokens#1{%
\edef\reserved@a{#1}%
\showtokens\expandafter
\expandafter\expandafter{\expandafter\reserved@a}}
% \end{macrocode}
% \end{macro}
%
% Now the rollback code.
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\@if@DeclareRobustCommand}
%<latexrelease> {Undefine \@if@DeclareRobustCommand, \@if@newcommand,
%<latexrelease> \@copy@DeclareRobustCommand, \@copy@newcommand,
%<latexrelease> \@show@DeclareRobustCommand, \@show@newcommand}%
%<latexrelease>\let\@if@DeclareRobustCommand\@undefined
%<latexrelease>\let\@copy@DeclareRobustCommand\@undefined
%<latexrelease>\let\@show@DeclareRobustCommand\@undefined
%<latexrelease>\let\@if@newcommand\@undefined
%<latexrelease>\let\@copy@newcommand\@undefined
%<latexrelease>\let\@show@newcommand\@undefined
%
%<latexrelease>\let\copy@kernel@robust@command\@undefined
%<latexrelease>\let\show@kernel@robust@command\@undefined
%<latexrelease>\let\@show@newcommand@aux\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
%
% \end{macro}
%
%
% \subsubsection{Showing environments}
%
% \begin{macro}{\ShowEnvironment}
% \changes{v1.5s}{2022/11/24}{Added \cs{ShowEnvironment}}
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2023-06-01}{\ShowEnvironment}
%<latexrelease> {Add \ShowEnvironment}%
%<*2ekernel|latexrelease>
% \end{macrocode}
%
% \cs{ShowEnvironment} is quite similar to \cs{ShowCommand}. We will
% pass the environment \meta{env} around as the macro
% \cs[no-index]{env}, because \cs{robust@command@act} expects a single
% token.
% \begin{macrocode}
\def\ShowEnvironment#1{%
\expandafter\@show@environment\csname #1\endcsname}
\long\def\@show@environment#1{%
\robust@command@act
\@showenvironmentlisthook#1%
\@show@normalenv#1}
% \end{macrocode}
%
% \begin{macro}{\@showenvironmentlisthook}
% This is similar to \cs{@showcommandlisthook}, but uses the dedicated
% versions for environments.
% \begin{macrocode}
\def\@showenvironmentlisthook{%
{\@if@DeclareRobustCommand \@show@DeclareRobustCommand@env}%
{\@if@newcommand \@show@newcommand@env}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@show@newcommand@env}
% \begin{macro}{\@show@DeclareRobustCommand@env}
% These are similar to the command versions below, except they say
% \enquote{environment} and call \cs{@show@environment@end} to print
% the \cs{end} part.
% \begin{macrocode}
\long\def\@show@newcommand@env#1{%
\@show@environment@begin#1%
\expandafter\@show@newcommand@aux
\csname\@backslashchar\@expl@cs@to@str@@N#1\expandafter\endcsname
\expandafter{#1}\@show@typeout
\@show@environment@end#1}
\long\def\@show@DeclareRobustCommand@env#1{%
\@show@environment@begin#1%
\begingroup
\let\@show@tokens\@show@typeout
\let\@show@macro\@show@nonstop
\expandafter\show@kernel@robust@command
\csname\@expl@cs@to@str@@N#1 \endcsname
\endgroup
\@show@environment@end#1}
\long\def\@show@environment@begin#1{%
\typeout{> \string\begin{\@expl@cs@to@str@@N#1}=environment:}%
\typeout{\@expl@cs@argument@spec@@N#1->%
\@expl@cs@replacement@spec@@N#1.^^J}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@show@normalenv}
% \begin{macro}{\@show@environment@end}
% A \enquote{normal} environment is straightforward.
% \cs{@show@environment@end} needs to check if the \cs{end} part is
% defined and show it accordingly, otherwise the output would show
% gibberish.
% \begin{macrocode}
\long\def\@show@normalenv#1{%
\@show@environment@begin#1%
\@show@environment@end#1}
\long\def\@show@environment@end#1{%
\expandafter\@show@environment@end@aux
\csname end\@expl@cs@to@str@@N#1\endcsname#1}
\long\def\@show@environment@end@aux#1#2{%
\@show@tokens{\string\end{\@expl@cs@to@str@@N#2}%
\ifx\relax#1=undefined%
\else:^^J\@expl@cs@argument@spec@@N#1->%
\@expl@cs@replacement@spec@@N#1%
\fi}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@show@nonstop}
% \begin{macro}{\@show@typeout}
% And here some auxiliaries:
% \begin{description}
% \item[\cs{@show@nonstop}] same output as \cs{show}, but doesn't
% stop for interaction;
% \item[\cs{@show@typeout}] same output as \cs{showtokens}, but
% doesn't stop for interaction.
% \end{description}
% \begin{macrocode}
\def\@show@nonstop#1{%
\typeout{> \string#1=\@expl@cs@prefix@spec@@N#1macro:^^J%
\@expl@cs@argument@spec@@N#1->\@expl@cs@replacement@spec@@N#1.}}
\def\@show@typeout#1{\typeout{> #1.^^J}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% Now the rollback code.
% \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\ShowEnvironment}
%<latexrelease> {Undefine \ShowEnvironment}%
%<latexrelease>\let\ShowEnvironment\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
%
% \subsection{Internal defining commands}
%
% These commands are used internally to define other \LaTeX{}
% commands.
% \begin{macro}{\@ifundefined}
% \changes{LaTeX2e}{1993/11/23}{Redefined to remove a trailing \cs{fi}}
% Check if first arg is undefined or \cs{relax} and execute second or
% third arg depending,
% \changes{1.5c}{2018/01/06}{Avoid defining undefined commands to \cs{relax}}
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2018-04-01}{\@ifundefined}
%<latexrelease>{Leave commands undefined in \@ifundefined}%
%<*2ekernel|latexrelease>
% \end{macrocode}
% Version using |\ifcsname| to avoid defining undefined tokens to |\relax|.
% Defined here to simplify using unmatched |\fi|.
% \begin{macrocode}
\def\@ifundefined#1{%
\ifcsname#1\endcsname\@ifundefin@d@i\else\@ifundefin@d@ii\fi{#1}}
% \end{macrocode}
% \begin{macrocode}
\long\def\@ifundefin@d@i#1\fi#2{\fi
\expandafter\ifx\csname #2\endcsname\relax
\@ifundefin@d@ii
\fi
\@secondoftwo}
% \end{macrocode}
% \begin{macrocode}
\long\def\@ifundefin@d@ii\fi#1#2#3{\fi #2}
% \end{macrocode}
% Now test of engine.
% \begin{macrocode}
\ifx\numexpr\@undefined
% \end{macrocode}
% Classic version (should not be needed as etex is assumed).
% \begin{macrocode}
\def\@ifundefined#1{%
\expandafter\ifx\csname#1\endcsname\relax
\expandafter\@firstoftwo
\else
\expandafter\@secondoftwo
\fi}
\else\ifx\directlua\@undefined
% \end{macrocode}
% Use the |\ifcsname| defined above.
% \begin{macrocode}
\else
% \end{macrocode}
% Optimised version for Lua\TeX, using |\lastnamedcs|
% \begin{macrocode}
\def\@ifundefined#1{%
\ifcsname#1\endcsname
\expandafter\ifx\lastnamedcs\relax\else\@ifundefin@d@i\fi
\fi
\@firstoftwo}
% \end{macrocode}
% \begin{macrocode}
\long\def\@ifundefin@d@i#1#2#3#4#5{#1#2#5}
% \end{macrocode}
% \begin{macrocode}
\fi
\fi
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000-00-00}{\@ifundefined}
%<latexrelease>{Leave commands undefined in \@ifundefined}%
%<latexrelease>\def\@ifundefined#1{%
%<latexrelease> \expandafter\ifx\csname#1\endcsname\relax
%<latexrelease> \expandafter\@firstoftwo
%<latexrelease> \else
%<latexrelease> \expandafter\@secondoftwo
%<latexrelease> \fi}
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@qend}
% \begin{macro}{\@qrelax}
% The following define |\@qend| and |\@qrelax| to be the strings
% `|end|' and `|relax|' with the characters |\catcode|d 12.
% \begin{macrocode}
\edef\@qend{\expandafter\@cdr\string\end\@nil}
\edef\@qrelax{\expandafter\@cdr\string\relax\@nil}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@ifnextchar}
% \changes{LaTeX209}{1992/08/24}
% {(Rms) \cs{@ifnextchar} didn't work if its
% first argument was an equal sign.}
% \changes{v1.2q}{1995/10/02}
% {Use \cs{@let@token} }
% \changes{v1.3a}{1999/01/07}
% {made long}
% \changes{v1.3b}{1999/01/07}
% {extra \cs{long}. latex/2902}
% \changes{v1.3e}{1999/03/01}
% {remove extra \cs{long}. internal/2967}
% |\@ifnextchar| peeks at the following character and compares it
% with its first argument. If both are the same it executes its
% second argument, otherwise its third.
% \begin{macrocode}
\long\def\@ifnextchar#1#2#3{%
\let\reserved@d=#1%
\def\reserved@a{#2}%
\def\reserved@b{#3}%
\futurelet\@let@token\@ifnch}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\kernel@ifnextchar}
% \changes{v1.3g}{2004/01/23}{Added macro (pr/3501)}
% This macro is the kernel version of |\@ifnextchar| which is used
% in a couple of places to prevent the AMS variant from being used
% since in some places this produced chaos (for example
% if an \texttt{fd} file
% is loaded in a random place then the optional argument to
% |\ProvidesFile| could get printed there instead of being written
% only in the log file. This happened
% when there was a space or a newline between the mandatory and
% optional arguments! It should really be fixed in the
% \texttt{amsmath} package one day, but\ldots
%
% Note that there may be other places in the kernel where this version
% should be used rather than the original, but variable, version.
%
% \begin{macrocode}
\let\kernel@ifnextchar\@ifnextchar
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@ifnch}
% |\@ifnch| is a tricky macro to skip any space tokens that may
% appear before the character in question. If it encounters a space
% token, it calls \@xifnch.
% \changes{v1.2q}{1995/10/02}
% {Use \cs{@let@token} for internal/924, save \cs{reserved@e}}
% \begin{macrocode}
\def\@ifnch{%
\ifx\@let@token\@sptoken
\let\reserved@c\@xifnch
\else
\ifx\@let@token\reserved@d
\let\reserved@c\reserved@a
\else
\let\reserved@c\reserved@b
\fi
\fi
\reserved@c}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@sptoken}
% The following code makes |\@sptoken| a space token. It is
% important here that the control sequence |\:| consists of
% a non-letter only, so that the following whitespace is
% significant. Together with the fact that the equal sign
% in a |\let| may be followed by only one optional space
% the desired effect is achieved.
% NOTE: the following hacking must precede the definition of |\:|
% as math medium space.
% \begin{macrocode}
\def\:{\let\@sptoken= } \: % this makes \@sptoken a space token
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@xifnch}
% In the following definition of |\@xifnch|, |\:| is again used
% to get a space token as delimiter into the definition.
% \begin{macrocode}
\def\:{\@xifnch} \expandafter\def\: {\futurelet\@let@token\@ifnch}
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\@ifstar}
% \changes{v1.2u}{1995/10/16}{(DPC) New implementation, for /1910}
% The new implementation below avoids passing the \meta{true code}
% Through one more |\def| than the \meta{false code}, which previously
% meant that |#| had to be written as |####| in one argument, but |##|
% in the other. The |*| is gobbled by |\@firstoftwo|.
% \begin{macrocode}
\def\@ifstar#1{\@ifnextchar *{\@firstoftwo{#1}}}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@dblarg}
% \begin{macro}{\@xdblarg}
% \changes{v1.1g}{2004/01/23}{Use kernel version of
% \cs{@ifnextchar} (pr/3501)}
% \begin{macrocode}
\long\def\@dblarg#1{\kernel@ifnextchar[{#1}{\@xdblarg{#1}}}
\long\def\@xdblarg#1#2{#1[{#2}]{#2}}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@sanitize}
% The command |\@sanitize| changes the catcode of all special characters
% except for braces to `other'. It can be used for commands like
% |\index| that want to write their arguments verbatim. Needless to
% say, this command should only be executed within a group, or chaos
% will ensue.
%
% \begin{macrocode}
\def\@sanitize{\@makeother\ \@makeother\\\@makeother\$\@makeother\&%
\@makeother\#\@makeother\^\@makeother\_\@makeother\%\@makeother\~}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@onelevel@sanitize}
% \changes{v1.2c}{1994/10/30}{Macro added}
%
% This makes the whole ``meaning'' of |#1| (its one-level
% expansion) into catcode 12 tokens: it could be used in
% |\DeclareRobustCommand|.
%
% If it is to be used on default float specifiers, this should be
% done when they are defined.
% \begin{macrocode}
\def \@onelevel@sanitize #1{%
\edef #1{\expandafter\strip@prefix
\meaning #1}%
}
% \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\string@makeletter}
% \begin{macro}{\@string@makeletter}
% \begin{macro}{\char@if@alph}
% Iterates through a string, turning each alphabetic character into
% a catcode-11 token (partly undoes a \cs{detokenize}). Useful for
% \cs{ifx}-based string comparisons where \cs{detokenize}-ing the
% other string would break too much code.
%
% \changes{v1.5n}{2020/09/06}
% {Macro added}
%
% The macro uses \textsf{expl3}'s \cs{@expl@str@map@function@@NN} to
% iterate on the string (without losing spaces) and applies
% \cs{@string@makeletter} on each character. The latter checks if
% character is between a--z or A--Z, and uses \cs{@alph} or \cs{@Alph}
% to get the corresponding catcode-11 token. Other tokens are passed
% through unchanged.
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020/10/01}{\string@makeletter}
%<latexrelease> {Add \string@makeletter}%
%<*2ekernel|latexrelease>
\def\string@makeletter#1{%
\@expl@str@map@function@@NN#1\@string@makeletter}
\def\@string@makeletter#1{%
\char@if@alph{#1}%
{\@expl@char@generate@@nn{`#1}{11}}%
{#1}}
\def\char@if@alph#1{%
\ifnum0\ifnum`#1<`A 1\fi\ifnum`#1>`z 1\fi
\if\ifnum`#1>`Z @\fi\ifnum`#1<`a @\fi01\fi>0
\expandafter\@secondoftwo
\else
\expandafter\@firstoftwo
\fi}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%
%<latexrelease>\IncludeInRelease{0000/00/00}{\string@makeletter}
%<latexrelease> {Undefine \string@makeletter}%
%<latexrelease>\let\string@makeletter\@undefined
%<latexrelease>\let\@string@makeletter\@undefined
%<latexrelease>\let\char@if@alph\@undefined
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\makeatletter}
% \begin{macro}{\makeatother}
% \changes{v1.0n}{1994/05/10}{Added \cs{makeatletter} and
% \cs{makeatother} ASAJ.}
% Make internal control sequences accessible or inaccessible.
% \begin{macrocode}
\DeclareRobustCommand\makeatletter{\catcode`\@11\relax}
\DeclareRobustCommand\makeatother{\catcode`\@12\relax}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \section{Discretionary Hyphenation}
% \begin{macro}{\-}
% \changes{1.2x}{1995/12/13}{Documentation changed.}
% \changes{v1.5a}{2017/03/13}{Define \cs{-} in terms of \cs{hyphenchar}}
% \begin{macro}{\@dischyph}
% \changes{v1.0g}{1994/04/12}
% {Define \cs{@dischyph}, was previously in ltboxes.dtx}
% \changes{v1.5b}{2017/03/27}{Define \cs{@dischyph} after \cs{-}}
% \changes{v1.5j}{2020/05/11}{Do not overwrite \cs{-} under Lua\TeX}
% \end{macro}
% Moved here to be after the definition of |\DeclareRobustCommand|.
%
% The primitive |\-| command adds a discretionary hyphen using the
% current font's |\hyphenchar|. Monospace fonts are usually declared
% with |\hyphenchar| set to $-1$ to suppress hyphenation.
%
% \LaTeX, from \LaTeX2.09 in 1986 defined |\-| by
% \begin{verbatim}
% \def\-{\discretionary{-}{}{}}
% \end{verbatim}
% The following comment was added when these commands were first set
% up, 19 April 1986:
% \begin{quote}
% the |\-| command is redefined to allow it to work in the |\ttfamily|
% type style, where automatic hyphenation is suppressed by setting
% |\hyphenchar| to~$-1$. The original primitive \TeX{} definition is
% saved as |\@@hyph| just in case anyone needs it.
% \end{quote}
%
% \LaTeXe, between 1993 and 2017, had a comment at this point
% saying that the definition ``would probably change'' because
% the definition always uses |-|. The definition used below
% was given in comments at this point during time.
%
% In 2017 we finally enabled this definition by default, with the
% older \LaTeX\ definition accessible via \textsf{latexrelease}
% as usual.
%
% In Lua\LaTeX\ the primitive definition of \cs{-} is used directly
% because it's use of extended hyphenation parameters means that \cs{-}
% works correctly even with \cs{hyphenchar} set to $-1$. This change
% makes \cs{-} under Lua\LaTeX\ compatible with language specific
% hyphenation characters.
%
% Temporary definition of |\@latex@info|, final definition is later.
% \begin{macrocode}
\def\@latex@info#1{}
% \end{macrocode}
%
% \begin{macrocode}
%</2ekernel>
%<latexrelease>\IncludeInRelease{2020/10/01}{\-}{Use primitive \- in Lua\LaTeX}%
%<*2ekernel|latexrelease>
\ifx\directlua\@undefined
\DeclareRobustCommand{\-}{%
\discretionary{%
\char \ifnum\hyphenchar\font<\z@
\defaulthyphenchar
\else
\hyphenchar\font
\fi
}{}{}%
}
\else
\let\-\@@hyph
\fi
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{2017/04/15}{\-}{Use \hyphenchar in \-}%
%<latexrelease>\DeclareRobustCommand{\-}{%
%<latexrelease> \discretionary{%
%<latexrelease> \char \ifnum\hyphenchar\font<\z@
%<latexrelease> \defaulthyphenchar
%<latexrelease> \else
%<latexrelease> \hyphenchar\font
%<latexrelease> \fi
%<latexrelease> }{}{}%
%<latexrelease>}
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000/00/00}{\-}{Use \hyphenchar in \-}%
%<latexrelease>\def\-{\discretionary{-}{}{}}
%<latexrelease>\EndIncludeInRelease
% \end{macrocode}
%
% \begin{macrocode}
%<*2ekernel|latexrelease>
\let\@dischyph=\-
%</2ekernel|latexrelease>
%<*2ekernel>
% \end{macrocode}
% \end{macro}
%
% Delayed from |ltvers.dtx|
% \begin{macrocode}
\newif\if@includeinrelease
\@includeinreleasefalse
% \end{macrocode}
%
% \changes{v1.5f}{2019/08/27}{Make various commands robust}
%
% Delayed from |ltplain.dtx|
% \begin{macrocode}
%</2ekernel>
%<*2ekernel|latexrelease>
%<latexrelease>\IncludeInRelease{2019/10/01}%
%<latexrelease> {\allowbreak}{Make various commands robust}%
\MakeRobust\allowbreak
\MakeRobust\bigbreak
\MakeRobust\break
\MakeRobust\dotfill
\MakeRobust\frenchspacing
\MakeRobust\goodbreak
\MakeRobust\hrulefill
\MakeRobust\medbreak
\MakeRobust\nobreak
\MakeRobust\nonfrenchspacing
\MakeRobust\obeylines
\MakeRobust\obeyspaces
\MakeRobust\slash
\MakeRobust\smallbreak
\MakeRobust\strut
\MakeRobust\underbar
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease> {\allowbreak}{Make various commands robust}%
%<latexrelease>
%<latexrelease>\kernel@make@fragile\allowbreak
%<latexrelease>\kernel@make@fragile\bigbreak
%<latexrelease>\kernel@make@fragile\break
%<latexrelease>\kernel@make@fragile\dotfill
%<latexrelease>\kernel@make@fragile\frenchspacing
%<latexrelease>\kernel@make@fragile\goodbreak
%<latexrelease>\kernel@make@fragile\hrulefill
%<latexrelease>\kernel@make@fragile\medbreak
%<latexrelease>\kernel@make@fragile\nobreak
%<latexrelease>\kernel@make@fragile\nonfrenchspacing
%<latexrelease>\kernel@make@fragile\obeylines
%<latexrelease>\kernel@make@fragile\obeyspaces
%<latexrelease>\kernel@make@fragile\slash
%<latexrelease>\kernel@make@fragile\smallbreak
%<latexrelease>\kernel@make@fragile\strut
%<latexrelease>\kernel@make@fragile\underbar
%<latexrelease>
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
% \end{macrocode}
%
%
% \begin{macro}{\g@addto@macro}
% Globally add to the end of a macro.
% This macro is used by the kernel to add to its internal hooks.
% \changes{v0.2a}{1993/11/14}{Made global}
% \changes{v0.2w}{1994/01/31}
% {Use toks register to avoid `hash' problems}
% \changes{v1.0o}{1995/05/17}
% {Make long for latex/1522}
% \changes{v1.0w}{1996/12/17}
% {Use \cs{begingroup} to save making a mathord}
% \changes{v1.0x}{1997/02/05}
% {missing percent /2402}
% \begin{macrocode}
\long\def\g@addto@macro#1#2{%
\begingroup
\toks@\expandafter{#1#2}%
\xdef#1{\the\toks@}%
\endgroup}
% \end{macrocode}
% \end{macro}
%
%
% \begin{macrocode}
%</2ekernel>
% \end{macrocode}
%
%
% \Finale
%
