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+% \iffalse meta-comment
+% Copyright (C) 2019--2020
+% by Phelype Oleinik <phelype.oleinik@latex-project.org>
+%
+% This work may be distributed and/or modified under the conditions of
+% the LaTeX Project Public License, either version 1.3c of this license
+% or (at your option) any later version. The latest version of this
+% license is in
+%
+% http://www.latex-project.org/lppl.txt
+%
+% and version 1.3c or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work is "maintained" (as per the LPPL maintenance status)
+% by Phelype Oleinik.
+%
+%<*package>
+\def\namedefDate{2020-06-20}
+\def\namedefVersion{1.0}
+%</package>
+%<*driver>
+\documentclass[a4paper,full,inline]{l3doc}
+\usepackage[T1]{fontenc}
+\usepackage{microtype}
+\usepackage{namedef}
+\usepackage{bookmark}
+\usepackage{xcolor}
+
+\def\TODO#1#{\begingroup\afterassignment\TODODO\let\tmp = }
+\def\TODODO{\setbox0=\vbox\bgroup\aftergroup\ENDTODO}
+\def\ENDTODO{\endgroup\ignorespaces}
+
+\begingroup
+ \lccode`~=`\%
+ \lowercase{\endgroup
+ \def\VRBCodes{^^A
+ \catcode`~=13
+ \def~{\%\global\linenofalse}}
+}
+\makeatletter
+\define@key{FV}{labelformat}{%
+ \def\FV@LabelFormat{#1}%
+ \ifx\FV@LabelFormat\FV@None
+ \let\FV@LabelFormat\relax
+ \fi}
+\def\FV@Label@ii[#1]#2\@nil{%
+ \def\@tempa{#1}%
+ \ifx\@tempa\empty
+ \def\FV@LabelBegin{\FV@LabelFormat#2}%
+ \else
+ \def\FV@LabelBegin{\FV@LabelFormat#1}%
+ \def\FV@LabelPositionBottomLine{\@ne}%
+ \fi
+ \def\FV@LabelEnd{\FV@LabelFormat#2}}
+\makeatother
+\DefineVerbatimEnvironment%
+ {example}{Verbatim}
+ {
+ gobble=3,
+ frame=single,
+ commandchars=|<>,
+ codes={\VRBCodes},
+ numbers=left,
+ labelformat=\rmfamily\bfseries,
+ }
+\def\mshow#1{> \string#1=\meaning#1}
+\newif\iflineno\linenotrue%\fi
+\def\theFancyVerbLine{^^A
+ \rmfamily
+ \scriptsize
+ \color{gray}^^A
+ \iflineno
+ \arabic{FancyVerbLine}^^A
+ \else
+ \global\addtocounter{FancyVerbLine}{-1}^^A
+ \fi
+ \global\linenotrue
+}
+\pdfstringdefDisableCommands{\let\footnotemark\relax}
+
+% Substitute lmtt/it by lmtt/sl
+\DeclareFontShape{T1}{lmtt}{lc}{it}{<->ssub*lmtt/lc/sl}{}
+
+\begin{document}
+ \overfullrule=5pt
+ \DocInput{\jobname.dtx}
+\end{document}
+%</driver>
+% \fi
+%
+% \GetFileInfo{\jobname.sty}
+%
+% \title{^^A
+% The \pkg{namedef} package\\
+% Named parameters in \TeX{} definitions^^A
+% \thanks{This file has version number \namedefVersion,
+% last revised \namedefDate.}
+% }
+%
+% \author{^^A
+% Phelype H. Oleinik\thanks
+% {^^A
+% E-mail:
+% \href{mailto:phelype.oleinik@latex-project.org}
+% {phelype.oleinik\meta{at}latex-project.org}^^A
+% }^^A
+% }
+%
+% \date{Released \namedefDate}
+%
+% \maketitle
+%
+% \begin{documentation}
+%
+% \section{Introduction}
+%
+% This package provides a somewhat dubious, however useful way to make
+% \TeX{} definitions using \cs{def} and the like. The usual way to
+% define a ``hello world'' macro is |\def\hello#1{Hello #1!}|. Sure,
+% this is easy (for people using this package, at least), but sometimes
+% I stumbled upon the case where I had a macro defined with something
+% like |\def\macro#1#2#3#4#5#6{#6#1#4#3#5#2}| and then I had to, for
+% whatever reason, add another argument before |#1|. Oh, the pain. But
+% OK, occupational hazard. And then I change my mind and needed to
+% revert. This package provides a way to give a semantic meaning to the
+% arguments of a definition such that it becomes clearer in meaning and
+% easier to change when an argument's identifier defines what it means
+% rather than its position in a list.
+%
+% \subsection{Features}
+%
+% This package defines a macro, \cs{named}, which acts like a prefix for
+% \cs{def} (the same way as \cs{long} and the like), and allows one to
+% rewrite the \cs{hello} macro like this:
+% |\named\def\hello#[who]{Hello #[who]!}|. Sure, a macro with one
+% argument won't see much benefit from it, but as soon as that number
+% increases, a better description of the arguments comes in handy.
+%
+% The package also defines a macro \cs{NamedDelim} which allows the user
+% to change the delimiter of the named parameters to their liking. For
+% example, after |\NamedDelim //| the example above changes to:
+% |\named\def\hello#/who/{Hello #/who/!}|. The default is
+% |\NamedDelim []|.
+%
+% The only dependency of this package is the \LaTeX3 programming layer,
+% \pkg{expl3}, thus this package works in any format and engine
+% supported by \pkg{expl3}. In \LaTeXe, load it with
+% |\usepackage{namedef}|, and in other formats with
+% |\input namedef.sty|.
+%
+% \subsection{Feedback}
+%
+% Bugs, feature requests, or suggestions are most welcome. You can send
+% them by e-mail or to the source code repository at
+% \url{https://github.com/PhelypeOleinik/namedef}.
+%
+% \section{Usage}
+%
+% \begin{function}{\named}
+% \begin{syntax}
+% \cs{named}\meta{other~prefixes}\meta{\cs[no-index]{(e,g,x)def}}^^A
+%\meta{parameter text}\marg{replacement text}
+% \end{syntax}
+% The \cs{named} macro will grab the \meta{other~prefixes}, the
+% \cs{def} command, the \meta{parameter~text} and
+% \meta{replacement~text}, and will replace every ocurrence of
+% |#[|\meta{text}|]| by a suitable |#|\meta{number} for \TeX{} to
+% carry on with the definition.
+%
+% The \meta{other~prefixes} can be any combination of \cs{long},
+% \cs{outer}, \cs{global}, and \cs{protected}. As for \TeX, their
+% relative order doesn't matter, except that \cs{named} must appear
+% \emph{before} any \cs{global} prefix. Other prefixes are detected
+% whether placed before or after \cs{named}.
+%
+% The \cs{def} command can be anything. The package will not check the
+% validity of the command, it will simply drag the token along until
+% the point where the definition is made. This allows one to use any
+% of \TeX's primitive \cs{def} commands as well as, for instance,
+% \pkg{expl3}'s \cs{cs_new:Npn} or the like. However \cs{named} will
+% not work with \LaTeX's \cs{newcommand} or \pkg{xparse}'s
+% \cs{NewDocumentCommand} and the like because their syntax is
+% completely different.
+%
+% The \meta{parameter~text} is the same \meta{parameter~text} that
+% would be used if the \cs{named} prefix wasn't used with the
+% difference that all |#|\meta{number} must be replaced by a
+% |#[|\meta{name}|]|. The characters |[| and |]| are mandatory and the
+% character |]| cannot appear in \meta{name}, however |[| and |]| can
+% still appear in the \meta{parameter~text} without restriction; the
+% special meaning is only applied after a parameter token (|#|).
+% \meta{name} can be anything that when fully expanded returns a
+% string of characters (anything valid in |\csname|\dots|\endcsname|).
+% The \meta{parameter~text} cannot, however, contain numbered
+% parameters anymore (|#1|,~|#2|,~\dots).
+% \TODO{This is not enforced... What should be done in this case?}
+%
+% The \meta{replacement~text} is also the same \meta{replacement~text}
+% that would be used otherwise, with all |#|\meta{number} replaced by
+% |#[|\meta{name}|]|.
+% \end{function}
+%
+% \begin{function}{\NamedDelim,\globalNamedDelim}
+% \begin{syntax}
+% \cs{NamedDelim}\meta{begin-token}\meta{end-token}
+% \cs{globalNamedDelim}\meta{begin-token}\meta{end-token}
+% \end{syntax}
+% These macros change the delimiter of the named parameters from the
+% default |#[|\meta{name}|]| to
+% |#|\meta{begin-token}\meta{name}\meta{end-token}. Both delimiters
+% must be one single non-macro token. Valid delimiters are character
+% tokens with catcode $3$, $4$, $7$, $8$, $11$, $12$, or $13$
+% (see section~\ref{sec:delimiters}).
+%
+% \cs{globalNamedDelim} is the same as \cs{NamedDelim} except that the
+% effect of the former has global scope, while the latter is local to
+% a group. While you can use both, you should be careful not to
+% interleave them too much or you might exhaust \TeX's save stack.
+%
+% Delimiters are matched based on their character code (using \cs{if})
+% so changes in their category code doesn't matter as long as that
+% change doesn't prevent the character from becoming a token or the
+% category code isn't \enquote{too special} :-) \quad (see above).
+%
+% The choice of delimiter is mostly ``what you like better''. Neither
+% the delimter tokens nor the name of the parameter make it to the
+% macro itself. They are just code-level abstractions. Thus the
+% delimiter should be something that the person writing the code can
+% easily distinguish from the rest of the code. For example, the code
+% |\NamedDelim xz \named\def\test#xyz{xyz#xyzxyz}| works, but its
+% readability is questionable.
+% \end{function}
+%
+% \subsection{Limitations}
+%
+% As already stated the command does not work (and I don't intend to
+% make it work) with \LaTeXe's \cs{newcommand} and its family because
+% a) the argument specification is by the number of arguments, so you
+% can't ``declare'' them as with \cs{def}, and b) because it's supposed
+% to be used for user-level interfaces, which usually (and preferably)
+% have a low argument count, so numbering shouldn't be a problem.
+% That said, see section~\ref{sec:newcommand}.
+%
+% For \pkg{xparse}'s \cs{NewDocumentCommand} the situation is the same.
+% Other than these, \cs{named} should work for whatever type of
+% definition that uses \TeX's \cs{def} syntax.
+%
+% Another limitation that I'd like to change in a future release (but
+% still don't know the best way to make the interface) is to support
+% definition commands which go beyond the
+% \meta{parameter~text}|{|\meta{replacement~text}|}| syntax. For
+% instance, in \pkg{expl3} a conditional that checks whether its
+% argument is negative can be defined like this (for integers, of
+% course):
+% \begin{Verbatim}
+% \prg_new_conditional:Npnn \namedef_if_negative:n #1 { T, F, TF }
+% {
+% \if_int_compare:w #1 < 0
+% \prg_return_true:
+% \else:
+% \prg_return_false:
+% \fi:
+% }
+% \end{Verbatim}
+% And if one tried to use \cs{named} in that definition it would fail
+% because this command takes one extra argument before the
+% \meta{replacement~text}. Something could be done to allow one (or
+% more) extra argument before the \meta{replacement~text}.
+%
+% \medskip
+% One serious limitation is when used with definitions that expand their
+% argument, namely \cs{edef} and \cs{xdef}. This type of definition
+% expands tokens as it reads them, possibly changing their meaning
+% during the process. \cs{named}, however, first grabs the definition as
+% argument to process the named arguments before actually performing the
+% definition, so these ``unexpected'' changes of meaning might make the
+% code misbehave. While writing this manual I could think of two (and a
+% half) situations which will be problematic and how to work around them
+% (sorry, no solution for now; suggestions are welcome :).
+%
+%^^A \begingroup
+% \edef\hash{\string#}
+% \edef\¿{\csname @gobble\expandafter\endcsname\string\\}
+% \def\nedeft{\ttfamily\¿named\¿edef\¿test}
+%
+% \subsubsection{\nedeft\{\¿string\#[arg]\}}
+% \label{sec:edef wa1}
+%
+% The normal (no \cs{named}) counterpart of this one is a perfectly
+% valid definition: |\edef\test{\string#1}|. While expanding the
+% \meta{replacement~text}, \cs{string} turns the parameter token |#|$_6$
+% into a character |#|$_{12}$, thus defining |\test| to expand to the
+% two characters |#1|. When using \cs{named}, however, the replacement
+% routine doesn't know what \cs{string} does to the token next to it, so
+% it goes on and treats |#[arg]| as one named argument only to find out
+% that it was never defined in the \meta{parameter~text}, so it aborts
+% the definition with an error.
+%
+% This will occur in the specific case where the user wishes to have the
+% macro expand to the characters |#[arg]|, without replacement by a
+% parameter. In this case the work-around is to temporarily switch the
+% delimiter tokens of \cs{named}'s scanner:
+% \begin{Verbatim}
+% \NamedDelim||
+% \named\edef\test{\string#[arg]}
+% \NamedDelim[]
+% \end{Verbatim}
+% in which case the scanner will still see the |#| as a parameter token
+% but since it is no longer followed by a delimiter, it will be simply
+% passed on to the definition. Afterwards, at the time \TeX{} tries to
+% carry on with the definition, \cs{string} will do its thing to |#|
+% without further problems.
+%
+% \subsubsection{\nedeft\#[arg]\{\¿string\}\#[arg]\}}
+% \label{sec:edef wa2}
+%
+% This one, as the previous, works fine without \cs{named}:
+% |\edef\test#1{\string}#1}|. Again, when \TeX{} scans this definition,
+% it will expand \cs{string} which will turn the end group token |}|$_2$
+% into a character |}|$_{12}$, which will have \TeX{} end the definition
+% with the next~|}|$_2$, after the |#1|. This only works because \TeX{}
+% does not grab the whole thing as argument before expanding. Which is
+% precisely what \cs{named} does.
+%
+% When \cs{named} grabs the definition as argument the first |}|
+% ends the \meta{replacement~text}, so what \cs{named} effectively sees
+% is |\edef\test#[arg]{\string}|, which is then processed (|#[arg]| is
+% replaced by |#1|) and left back in the input stream for \TeX{} to do
+% its thing, however the replacement |#[arg]| is never replaced:
+% |\edef\test#1{\string}#[arg]}|, then when \TeX{} tries to do the
+% definition it will complain about an ``! Illegal parameter number in
+% definition of |\test|.''
+%
+% The work-around in this case is to do a dirty brace trick to lure
+% \cs{named} into grabbing the whole thing as argument, but which will
+% disappear at the time \TeX{} performs the expansion and definition.
+% One option is |\iffalse{\fi|:
+% \begin{Verbatim}
+% \named\edef\test#[arg]{%
+% \iffalse{\fi \string}#[arg]}
+% \end{Verbatim}
+% In this example \cs{named} will process everything, but at the time of
+% the definition the entire |\iffalse{\fi| thing expands to nothing and
+% the final definition becomes the same as the one without \cs{named}.
+% The |\iffalse{\fi| block can also be left in the definition
+% \emph{without} named and the result will be the same. One could argue
+% that using the brace hack is safer because it doesn't change the
+% definition, yet avoid problems when grabbing the definition as
+% argument in a general situation.
+%
+% \let\SVsubsec\thesubsubsection
+% \def\thesubsubsection{^^A
+% \thesubsection .\number\numexpr\value{subsubsection}-1,5}
+%
+% \subsubsection{\nedeft\#[arg]\{\¿string\{\#[arg]\}}
+% \label{sec:edef wa3}
+%
+% \let\thesubsubsection\SVsubsec
+%^^A \endgroup
+%
+% This is rather similar to the previous one, except that the brace
+% later-to-be-detokenized begins a group: |\edef\test#1{\string{#1}|.
+% Here \TeX{} also expands \cs{string} and makes |{|$_1$ a |{|$_{12}$
+% which does not count in the brace balancing. \cs{named}, however, will
+% count it when grabbing the definition as argument and will require one
+% more |}|$_2$. If the code is run as is \TeX{} will probably report a
+% ``File ended while scanning use of \dots'' error unless there happens
+% to be a matching |}|$_2$ somewhere else, in which case the definition
+% will just go wrong. The work-around here is the same as the one
+% before, with |}| instead:
+% \begin{Verbatim}
+% \named\edef\test#[arg]{%
+% \string{#[arg]\iffalse}\fi}
+% \end{Verbatim}
+% This will ensure that \cs{named} will see the |}| it needs to grab the
+% definition correctly and will disappear once the definition is done.
+%
+% \subsection{Invalid delimiters}
+% \label{sec:delimiters}
+%
+% The delimiters that can be used should be character tokens with
+% catcode $3$, $4$, $7$, $8$, $11$, $12$, or $13$. Characters with
+% catcode $0$, $5$, $9$, $14$, and $15$ don't produce tokens to start
+% with, so they can't possibly be used. The remaining category codes
+% are currently disallowed in the code because they make the input
+% ambiguous or because they make the implementation more complex with no
+% real advantage.
+%
+% Catcodes $1$ and $2$ (begin-/end-group) cannot be used because they
+% become indistinguishable from the braces that delimit the
+% \meta{parameter~text} of the definition, so the input is ambiguous.
+%
+% Catcode $6$ (macro parameter) cannot be used because it gets hard to
+% distinguish a named parameter from some text surrounded by parameter
+% tokens. For example in: |\named\edef\foo#name#{\string#then#name#}|,
+% \pkg{namedef} would raise an error on |#then#| (unknown parameter)
+% without knowing that the first |#|$_{6}$ becomes |#|$_{12}$ and the
+% actual parameter is |#name#|\dots Or is it? I'm not entirely convinced
+% of my own argument, so this might be implemented in the future.
+%
+% Catcode $10$ (blank space) is possible but it requires a hanful of
+% extra precautions to avoid losing the space when passing arguments
+% around. Since it makes for a strange-looking syntax (our eyes are
+% trained to ignore spaces), this is not supported.
+%
+% \section{Boring examples}
+%
+% The following examples show two definitions each, which are the same,
+% but the second uses \cs{named}. The third line in each example shows
+% the \cs{meaning} of the defined macro.
+%
+% First the basics, replacing a numbered parameter by a named one:
+% \named\def\hello#[who]{Hello #[who]!}
+% \begin{example}[label=Basics]
+% \def\hello#1{Hello #1!}
+% \named\def\hello#[who]{Hello #[who]!}
+% |mshow|hello
+% \end{example}
+% \smallskip
+%
+% Prefixes can be added at will after the \cs{named} prefix:
+% \named\protected\long\edef\hello#[who]{Hello #[who]!}
+% \begin{example}[label=Prefixes]
+% \protected\long\edef\hello#1{Hello #1!}
+% \named\protected\long\edef\hello#[who]{Hello #[who]!}
+% |mshow|hello
+% \end{example}
+% \smallskip
+%
+%^^A Whatever prefixes put before \cs{named} will be lost. Notice that
+%^^A even though \cs{protected} is used, the macro itself is not defined
+%^^A with \cs{protected}:
+%^^A \protected\named\long\edef\hello#[who]{Hello #[who]!}
+%^^A \begin{example}[label=Wrong Prefixes]
+%^^A \protected \long\edef\hello#1{Hello #1!}
+%^^A \protected\named\long\edef\hello#[who]{Hello #[who]!}
+%^^A |mshow|hello
+%^^A \end{example}
+%^^A \smallskip
+%
+% This example is just to show that the named argument delimiter doesn't
+% interfere with the text in the macro:
+% \named\def\hello[#[who]]{Hello #[who]!}
+% \begin{example}[label=Argument delimited by \texttt{[} and \texttt{]}]
+% \def\hello[#1]{Hello #1!}
+% \named\def\hello[#[who]]{Hello #[who]!}
+% |mshow|hello
+% \end{example}
+% \smallskip
+%
+% However, for readability, the delimiter can be changed to something
+% else:
+% \named\def\hello[#[who]]{Hello #[who]!}
+% \begin{example}[label=Argument delimited by \texttt{[} and \texttt{]},
+% commandchars=/<>,firstnumber=0]
+% \NamedDelim{|}{|}
+% \def\hello[#1]{Hello #1!}
+% \named\def\hello[#|who|]{Hello #|who|!}
+% /mshow/hello
+% \end{example}
+% \smallskip
+%
+% This example demonstrates multiple arguments and arbitrary
+% \meta{parameter~text}:
+% \named\def\cfbox #[color] to #[width]#[content]{%
+% \fbox{\hbox to #[width]{\color{#[color]}#[content]}}}
+% \begin{example}[label=More arguments]
+% \def\cfbox #1 to #2#3{\fbox{\hbox to #2{\color{#1}#3}}}
+% \named\def\cfbox #[color] to #[width]#[content]{%
+% \fbox{\hbox to #[width]{\color{#[color]}#[content]}}}
+% |mshow|cfbox
+% \end{example}
+% \smallskip
+%
+% \TeX's weird |#{| argument can be used as well:
+% \named\def\cbox #[color] to #[width]#{^^A
+% \hbox to #[width]\bgroup\color{#[color]}\let\next= }
+% \begin{example}[label=Weird arguments]
+% \def\cbox #1 to #2#{\hbox to #2\bgroup\color{#1}\let\next= }
+% \named\def\cbox #[color] to #[width]#{%
+% \hbox to #[width]\bgroup\color{#[color]}\let\next= }
+% |mshow|cbox
+% \end{example}
+% \smallskip
+%
+% {\NamedDelim XX
+% \named\xdef\test{\string#[arg]}}
+% \begin{example}[commandchars=/<>, label=
+% \texttt{\string\edef} workaround \ref{sec:edef wa1}]
+% \edef\test{\string#[arg]}
+% \NamedDelim || /global/linenofalse
+% \named\edef\test{\string#[arg]} /global/linenofalse
+% \NamedDelim []
+% /mshow/test
+% \end{example}
+% \smallskip
+%
+% \named\edef\test#[arg]{\iffalse{\fi\string}#[arg]}
+% \begin{example}[label=
+% \texttt{\string\edef} workaround \ref{sec:edef wa2}]
+% \edef\test#1{\string}#1}
+% \named\edef\test#[arg]{\iffalse{\fi\string}#[arg]}
+% |mshow|test
+% \end{example}
+% \smallskip
+%
+% \named\edef\test#[arg]{\string{#[arg]\iffalse}\fi}
+% \begin{example}[label=
+% \texttt{\string\edef} workaround \ref{sec:edef wa3}]
+% \edef\test#1{\string{#1}
+% \named\edef\test#[arg]{\string{#[arg]\iffalse}\fi}
+% |mshow|test
+% \end{example}
+% \smallskip
+%
+% \section{Interesting\protect\footnotemark\ examples}
+% \footnotetext{Terms and Conditions may apply.}
+%
+% These examples shows a few more elaborate ways to use \pkg{namedef}.
+%
+% \subsection{Extended \cs{newcommand}}
+% \label{sec:newcommand}
+%
+% Here's an implementation to allow the syntax of \pkg{namedef} in
+% \cs{newcommand}. It uses \pkg{xparse} to handle optional arguments,
+% and uses \cs{newcommand} itself to define (possibly) optional argument
+% handling, so the resulting command uses \LaTeXe's command parsing
+% machinery.
+%
+% The syntax of the defined command is:
+%
+% |\newnamedcommand|\meta{*}\cs[no-index]{\meta{cmd}}\oarg{arg-list}^^A
+% [\meta{opt}=\meta{default}]\marg{definition}
+%
+% \noindent where everything is the same as in regular \cs{newcommand},
+% except for the optional arguments \meta{arg-list} and
+% \meta{opt}=\meta{default}. \meta{arg-list} should be a
+% comma-separated list of named parameters as \cs{named} would expect,
+% and \meta{opt} is a named parameter, and \meta{default} is its default
+% value. The usage would be something like:
+%
+% |\newnamedcommand\foo[#[one],#[two]][#[opt]=default]%|\par
+% \quad|{#[one], #[two], and #[opt]}|
+%
+% \noindent which translates to:
+%
+% |\newcommand\foo[3][default]%|\par
+% \quad|{#2, #3, and #1}|
+%
+% First, load \pkg{xparse} and \pkg{namedef}, and define the top-level
+% commands to use a common |\NNC_newcommand:NnNnnn|.
+% |\NNC_newcommand:NnNnnn| will store the mandatory arguments in
+% a \texttt{seq} variable for easier access, then call
+% |\__NNC_newcommand:NnNn| to do the \cs{newcommand} part of the job,
+% and |\__NNC_named_def:nNnn| to \cs{named} part.
+% |\new...|, |\renew...|, and |\provide...| versions are defined, but
+% since a \cs{def} is used later with no checking, the behaviour is
+% not exactly the same as you'd get with \cs{newcommand} in this regard.
+%
+% \begin{example}
+% \usepackage{namedef}
+% \usepackage{xparse}
+% \ExplSyntaxOn
+% \seq_new:N \l__NNC_args_seq
+% \scan_new:N \s__NNC
+% \NewDocumentCommand \newnamedcommand { s m o o m }
+% { \NNC_newcommand:NnNnnn \newcommand {#1} #2 {#3} {#4} {#5} }
+% \NewDocumentCommand \renewnamedcommand { s m o o m }
+% { \NNC_newcommand:NnNnnn \renewcommand {#1} #2 {#3} {#4} {#5} }
+% \NewDocumentCommand \providenamedcommand { s m o o m }
+% { \NNC_newcommand:NnNnnn \providecommand {#1} #2 {#3} {#4} {#5} }
+% \named \cs_new_protected:Npn \NNC_newcommand:NnNnnn
+% #[newcmd] #[star] #[cmd] #[args] #[opt] #[defn]
+% {
+% \seq_clear:N \l__NNC_args_seq
+% \IfValueT {#[args]}
+% { \seq_set_from_clist:Nn \l__NNC_args_seq {#[args]} }
+% \__NNC_newcommand:NnNn #[newcmd] {#[star]} #[cmd] {#[opt]}
+% \__NNC_named_def:nNnn {#[star]} #[cmd] {#[opt]} {#[defn]}
+% }
+% \end{example}
+%
+% |\__NNC_newcommand:NnNn| does the \cs{newcommand} part of the job. It
+% takes the arguments read in by \pkg{xparse}, and translates them into
+% the \cs{newcommand} syntax. The number of items in the |#[args]|
+% parameter is counted and left within brackets, and the default value
+% of the optional argument is also left within another pair of brackets.
+% This step is executed with an empty definition because the named
+% parameters will cause havoc in \cs{newcommand}.
+%
+% \begin{example}[firstnumber=last]
+% \named \cs_new_protected:Npn \__NNC_newcommand:NnNn
+% #[newcmd] #[star] #[cmd] #[opt]
+% {
+% \use:x
+% {
+% \exp_not:N #[newcmd]
+% \IfBooleanT {#[star]} { * }
+% \exp_not:N #[cmd]
+% \seq_if_empty:NF \l__NNC_args_seq
+% { [ \seq_count:N \l__NNC_args_seq ] }
+% \IfValueT {#[opt]} { [ \__NNC_opt_value:w #[opt] \s__NNC ] }
+% { }
+% }
+% }
+% \cs_new:Npn \__NNC_opt_value:w #1 = #2 \s__NNC {#2}
+% \end{example}
+%
+% Now |\__NNC_named_def:nNnn| will do the \cs{named} part.
+% First the |#[star]| argument (if not present) becomes \cs{long}, and
+% then comes \cs{named} and \cs{def}. Then, if an optional argument was
+% given, the command we need to define is |\\foo| rather than |\foo|, so
+% use take care of that with \cs{token_to_str:N}, and then leave the
+% named parameter given for the optional argument within brackets.
+% If there's no optional argument, we just define |#[cmd]| (pretty
+% boring). Then we call \cs{seq_use:Nn} on the mandatory arguments to
+% lay them flat for \cs{named}, and then the parameter text (|#[defn]|),
+% unexpanded.
+%
+% \begin{example}[firstnumber=last]
+% \named \cs_new_protected:Npn \__NNC_named_def:nNnn
+% #[star] #[cmd] #[opt] #[defn]
+% {
+% \use:x
+% {
+% \IfBooleanF {#[star]} { \long }
+% \named \def
+% \IfValueTF {#[opt]}
+% {
+% \exp_not:c { \token_to_str:N #[cmd] }
+% [ \exp_not:o { \__NNC_opt_name:w #[opt] \s__NNC } ]
+% }
+% { \exp_not:N #[cmd] }
+% \seq_use:Nn \l__NNC_args_seq { }
+% { \exp_not:n {#[defn]} }
+% }
+% }
+% \cs_new:Npn \__NNC_opt_name:w #1 = #2 \s__NNC {#1}
+% \ExplSyntaxOff
+% \end{example}
+%
+% \end{documentation}
+%
+% \begin{implementation}
+%
+% \section{\pkg{namedef} Implementation}
+%
+% \begin{macrocode}
+%<*package>
+%<@@=namedef>
+% \end{macrocode}
+%
+% \subsection{Loading}
+%
+% \begin{macro}{\@@_end_package_hook:}
+% Load \pkg{expl3}, either through \cs{RequirePackage} or through
+% inputting the generic loader, depending on the format in use
+% (copied from Bruno Le Floch's \pkg{gtl}).
+% \begin{macrocode}
+\begingroup\expandafter\expandafter\expandafter\endgroup
+\expandafter\ifx\csname RequirePackage\endcsname\relax
+ \input expl3-generic.tex
+\else
+ \RequirePackage{expl3}[2018-05-15]
+\fi
+\ExplSyntaxOn
+\cs_if_exist:NTF \ProvidesExplPackage
+ {
+ \cs_new_eq:NN \@@_end_package_hook: \prg_do_nothing:
+ \ExplSyntaxOff
+ \ProvidesExplPackage
+ }
+ {
+ \cs_new_eq:NN \@@_end_package_hook: \ExplSyntaxOff
+ \group_begin:
+ \ExplSyntaxOff
+ \cs_set_protected:Npn \@@_tmp:w #1#2#3#4
+ {
+ \group_end:
+ \tl_gset:cx { ver @ #1 . sty } { #2 ~ v#3 ~ #4 }
+ \cs_if_exist_use:NF \wlog { \iow_log:x }
+ { Package: ~ #1 ~ #2 ~ v#3 ~ #4 }
+ }
+ \@@_tmp:w
+ }
+ {namedef} {\namedefDate} {\namedefVersion}
+ {Named parameters in TeX definitions (PHO)}
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Declarations}
+%
+% \begin{macro}{\flag @@_parm_count}
+% A flag (mis)used as a counter to keep track of the parameter number.
+% \begin{macrocode}
+\flag_new:n { @@_parm_count }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\c_@@_prefix_tl}
+% A prefix to use as name space for temporary macros.
+% \begin{macrocode}
+\tl_const:Nn \c_@@_prefix_tl { namedef~parm~-> }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\l_@@_macro_tl}
+% A token list to store the name of the macro meing defined for error
+% messages.
+% \begin{macrocode}
+\tl_new:N \l_@@_macro_tl
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\q_@@_mark,\q_@@_stop}
+% Quarks used throughout the package.
+% \begin{macrocode}
+\quark_new:N \q_@@_mark
+\quark_new:N \q_@@_stop
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\s_@@}
+% Scan mark used to skip code.
+% \begin{macrocode}
+\scan_new:N \s_@@
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_skip_to_scan_mark:w, \@@_skip_to_scan_mark:nw}
+% Consume everything up to \cs{s_@@}.
+% \begin{macrocode}
+\cs_new:Npn \@@_skip_to_scan_mark:w #1 \s_@@ { }
+\cs_new:Npn \@@_skip_to_scan_mark:nw #1 #2 \s_@@ {#1}
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_tmp:w}
+% A scratch macro.
+% \begin{macrocode}
+\cs_new_eq:NN \@@_tmp:w ?
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{The top-level \cs{named} macro}
+%
+% \begin{macro}{\named}
+% \begin{macro}{\@@_grab_prefix:nN}
+% Starts scanning ahead for prefixes and the definition
+% command. Once finished the scanning of prefixes, call
+% \cs{@@_replace_named:nNnn} to do the heavy lifting.
+% \begin{macrocode}
+\cs_new_protected:Npn \named { \@@_grab_prefix:nN { } }
+\cs_new_protected:Npn \@@_grab_prefix:nN #1 #2
+ {
+ \@@_if_prefix:NTF #2
+ { \@@_grab_prefix:nN }
+ { \@@_detect_prefixes:Nn \@@_kill_outer:nN }
+ { #1#2 }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[pTF]{\@@_if_prefix:N}
+% Checks against a list of valid prefixes and returns |true| or
+% |false| accordingly.
+% \begin{macrocode}
+\prg_new_conditional:Npnn \@@_if_prefix:N #1 { TF }
+ {
+ \if_int_compare:w 0
+ \if_meaning:w \tex_protected:D #1 1 \fi:
+ \if_meaning:w \tex_global:D #1 1 \fi:
+ \if_meaning:w \tex_outer:D #1 1 \fi:
+ \if_meaning:w \tex_long:D #1 1 \fi:
+ \if_meaning:w \scan_stop: #1 1 \fi:
+ = 1 \exp_stop_f:
+ \prg_return_true:
+ \else:
+ \prg_return_false:
+ \fi:
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\@@_detect_prefixes:Nn}
+% \begin{macro}[rEXP]{\@@_extract_prefixes:w}
+% \begin{macro}[rEXP]{
+% \@@_extract_protected:n, \@@_extract_protected_aux:w,
+% \@@_extract_long:n, \@@_extract_long_aux:w,
+% \@@_extract_outer:n, \@@_extract_outer_aux:w,
+% }
+% Defines a scratch macro \cs{@@_tmp:w} and queries its prefixes, then
+% forwards them to the the next macro to perform the parameter
+% replacement and definition.
+%
+% This code would be quite a lot simpler if \cs{outer} didn't exist.
+% First extract the meaning of \cs{@@_tmp:w}, and pass the prefixes
+% (before ``|macro:|'') to \cs{@@_extract_prefixes:w}, and then to
+% \cs{@@_extract_protected:n}, \cs{@@_extract_long:n}, and
+% \cs{@@_extract_outer:n} in turn to check if each of these prefixes
+% is there.
+%
+% \cs{global} can't be checked this way because it's different from
+% other prefixes in the sense that it affects the definition \emph{at
+% the time} of the definition, rather than at the time it is used.
+% I don't know if it's possible to detect a \cs{global} after it's
+% already consumed by \TeX.
+%
+% \TODO{\cs{afterassignment} tokens are lost. It would be nice if
+% it were possible to retrieve it and save until later.}
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_detect_prefixes:Nn #1 #2
+ {
+ \cs_set_nopar:Npn \@@_tmp:w { }
+ \use:x
+ {
+ \exp_not:N #1
+ {
+ \exp_after:wN \exp_after:wN
+ \exp_after:wN \@@_extract_prefixes:w
+ \exp_after:wN \token_to_meaning:N
+ \cs:w @@_tmp:w \cs_end: \s_@@
+ \exp_not:n {#2}
+ }
+ }
+ }
+\use:x
+ {
+ \cs_new:Npn \exp_not:N \@@_extract_prefixes:w ##1
+ \tl_to_str:n { macro: } ##2 \s_@@
+ {
+ \exp_not:N \@@_extract_protected:n {##1}
+ \exp_not:N \@@_extract_long:n {##1}
+ \exp_not:N \@@_extract_outer:n {##1}
+ }
+ }
+\cs_set_protected:Npn \@@_tmp:w #1 #2
+ {
+ \use:x
+ {
+ \cs_new:cpn { @@_extract_#1:n } ####1
+ {
+ \exp_not:c { @@_extract_#1_aux:w } ####1
+ \token_to_str:N #2 \scan_stop: \token_to_str:N #2 \s_@@
+ }
+ \cs_new:cpn { @@_extract_#1_aux:w } ####1
+ \token_to_str:N #2 ####2 \token_to_str:N #2 ####3 \s_@@
+ {
+ \exp_not:N \if_meaning:w \scan_stop: ####2
+ \exp_not:N \else:
+ \exp_not:c { tex_#1:D }
+ \exp_not:N \fi:
+ }
+ }
+ }
+\@@_tmp:w { protected } { \protected }
+\@@_tmp:w { long } { \long }
+\@@_tmp:w { outer } { \outer }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Main routine}
+%
+% \begin{macro}{\@@_kill_outer:nN}
+% \begin{macro}{\@@_start:nNp, \@@_replace_named:nNnn}
+% \begin{macro}{\@@_replace_parameter:Nn, \@@_parameter_output:nnw}
+% \begin{macro}{\@@_handle_parameter:nN}
+% \begin{macro}{\@@_define:nnnN}
+% Here we play dirty: abuse the fact that \cs{exp_not:N} temporarily
+% makes the \cs{noexpand}ed control sequence temporarily equal to
+% \cs{relax}. But rather than using it in an \cs{edef} or whatnot,
+% hit \cs{exp_not:N} with \cs{exp_after:wN}, and then quickly grab
+% it with \cs{@@_start:nNp}, so it's safe to grab it, even if it's
+% \cs{outer}. If that wasn't bad enough, do it once again to make
+% it equal to \cs{relax} in the scope of \cs{@@_replace_named:nNnn}
+% so that it doesn't blow up.
+%
+% \TODO{Currently |\named\def{\foo}{bar}| works, but perhaps it
+% shouldn't.}
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_kill_outer:nN #1
+ {
+ \cs_set:Npn \@@_tmp:w { \@@_start:nNp {#1} }
+ \exp_after:wN \@@_tmp:w \exp_not:N
+ }
+\cs_new_protected:Npn \@@_start:nNp #1 #2 #3 #
+ {
+ \group_begin:
+ \int_set:Nn \tex_escapechar:D { `\\ }
+ \exp_after:wN \cs_set_eq:NN \exp_not:N #2 \scan_stop:
+ \@@_replace_named:nNnn {#1} #2 {#3}
+ }
+% \end{macrocode}
+%
+% Here the actual replacement of named parameters by numbered ones
+% takes place. A group is started to revert the flag and all the
+% defined temporary macros.
+%
+% \cs{@@_replace_parameter:Nn} \cs{@@_in_parameter:nN} starts
+% replacing a dummy macro in the generic parameter replacement routine
+% by the macro which counts the parameters and aliases the named
+% parameters with numbered ones. Finally it starts
+% \cs{@@_replace_parm:Nn}, which scans the \meta{parameter~text} for
+% the named parameters and replaces them by numbered ones. The second
+% output argument of \cs{@@_replace_parm:Nn} is a list of definitions
+% which assign a number to each named parameter so that they can be
+% used in the next step.
+%
+% \cs{@@_replace_parameter:Nn} \cs{@@_in_replacement:nN} then starts
+% by replacing the same dummy macro by one which will replace the
+% named parameter by its number. Again \cs{@@_replace_parm:Nn} is
+% started, and its output is the already-processed part of the
+% \meta{replacement~text}.
+%
+% The output of both steps is inserted after \cs{@@_define:nnnN} (it's
+% missing two arguments in the definition of
+% \cs{@@_replace_named:nNnn}). After all that is done, all the named
+% parameters were replaced by numbered ones, so \cs{@@_define:nnnN}
+% can do its thing.
+%
+% A final quark is put in the input stream for recovery from errors.
+% In a successful run this quark is removed by \cs{@@_define:nnnN}.
+% \begin{macrocode}
+\cs_new_protected:Npn \@@_replace_named:nNnn #1 #2 #3 #4
+ {
+ \tl_set:Nx \l_@@_macro_tl { \token_to_str:N #2 }
+ \@@_replace_parameter:Nn \@@_in_parameter:nN {#3}
+ \@@_replace_parameter:Nn \@@_in_replacement:nN {#4}
+ \@@_define:nnnN {#1} #2
+ \s_@@
+ }
+\cs_new_protected:Npn \@@_define:nnnN #1 #2 #3 #4
+ {
+ \group_end:
+ #3#4#2{#1}
+ }
+\cs_new_protected:Npn \@@_replace_parameter:Nn #1 #2
+ {
+ \cs_set_eq:NN \@@_handle_parameter:nN #1
+ \@@_replace_parm:Nn \@@_parameter_output:nnw {#2}
+ }
+\cs_new_eq:NN \@@_handle_parameter:nN ?
+\cs_new_protected:Npn \@@_parameter_output:nnw #1 #2
+ #3 \@@_define:nnnN
+ { #2 #3 \@@_define:nnnN {#1} }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\@@_in_parameter:nN, \@@_in_replacement:nN}
+% These two functions handle the named parameters when they are found
+% in the \meta{parameter~text} and \meta{replacement~text},
+% respectively.
+%
+% \cs{@@_in_parameter:nN} checks if the named parameter already exists
+% (with \cs{relax} being |true|) and, in such case, throws an error
+% and inserts the number already set for that named parameter.
+% Otherwise the parameter is \cs{let} to
+% \cs{relax} so that if it is found later an error is issued. Setting
+% a macro to \cs{relax} is an expandable way to define it (the same
+% approach as in \pkg{l3flag}). After that,
+% the \cs{flag @@_parm_count} is raised once and its height is used as
+% the parameter number. The current parameter tokens and the parameter
+% number are flushed to the first (left) output slot, and a definition
+% |\cs_set:cpn {|\cs{c_@@_prefix_tl}~\meta{name}|} {|\meta{number}|}|
+% is appended to the second (right) output slot so that the names can
+% be used in the \meta{replacement~text}.
+%
+% In case of a repeated parameter it is tricky to do anything
+% sensible. In a normal definition, when \TeX{} sees a repeated
+% parameter number (like in |\def\foo#1#1{}|) it just uses the wrong
+% number to a parameter number not yet taken, or ignores the parameter
+% if there's already nine before that. However here we can't guess
+% the name of the next parameter, so we can't do much. The easiest
+% way out is to just use the same parameter number as before and go
+% on with out job: at the end, \TeX{} will complain again about this.
+% \begin{macrocode}
+\cs_new:Npn \@@_in_parameter:nN #1
+ {
+ \if_cs_exist:w \c_@@_prefix_tl #1 \cs_end:
+ \exp_after:wN \use_i:nn
+ \else:
+ \exp_after:wN \use_ii:nn
+ \fi:
+ { \msg_expandable_error:nnn { namedef } { repeated-parm } {#1} }
+ {
+ \exp_after:wN \use_none:n \cs:w \c_@@_prefix_tl #1 \cs_end:
+ \flag_raise:n { @@_parm_count }
+ }
+ \exp_args:Nf \@@_append_output:nnNwnn
+ { \flag_height:n { @@_parm_count } }
+ {#1}
+ }
+% \end{macrocode}
+%
+% \cs{@@_in_replacement:nN} also checks if the named parameter exists,
+% however now it will be \emph{not} be \cs{relax}, but the number
+% defined earlier, so \cs{cs_if_exist:cTF} can be safely used. If the
+% parameter does not exist it was never declared in the
+% \meta{parameter~text} (somewhat like |\def#1{#2}|), then raise an
+% error and abort.
+% Otherwise just flush |#|\meta{number}.
+% \begin{macrocode}
+\cs_new:Npn \@@_in_replacement:nN #1 #2
+ {
+ \cs_if_exist:cTF { \c_@@_prefix_tl #1 }
+ {
+ \exp_args:Nf \@@_append_output:nnNwnn
+ { \use:c { \c_@@_prefix_tl #1 } }
+ { }
+ }
+ {
+ \msg_expandable_error:nnn { namedef } { unknown-parm } {#1}
+ \exp_args:Ne \@@_append_output:nnNwnn
+ { #2 \@@_begin_name_token: #1 \@@_end_name_token: }
+ { \cs_end: { } \use_none:nn }
+ }
+ #2
+ }
+% \end{macrocode}
+% \end{macro}
+%
+% \subsection{Scanning routine}
+%
+% \begin{macro}[EXP]{\@@_replace_parm:Nn}
+% \begin{macro}[EXP]{\@@_replace_loop:w}
+% \begin{macro}[EXP]{\@@_replace_end:wnn, \@@_flush:nw}
+% \begin{macro}[EXP]{\@@_append_output:nnNwnn}
+% \begin{macro}[EXP]{\@@_abort_definition:w}
+% \cs{@@_replace_parm:Nn} uses the same looping principle as in
+% \pkg{l3tl}'s \cs{__tl_act:NNNnn}. It scans the input (here, the
+% \meta{parameter~text} and \meta{replacement~text}, separately) token
+% by token, differentiating spaces, braced tokens (groups), and
+% \enquote{normal} tokens.
+% \begin{macrocode}
+\cs_new:Npn \@@_replace_parm:Nn #1 #2
+ {
+ \exp_after:wN #1
+ \exp:w
+ \@@_replace_loop:w #2
+ \q_@@_mark \q_@@_stop { } { }
+ }
+\cs_new:Npn \@@_replace_loop:w #1 \q_@@_stop
+ {
+ \tl_if_head_is_N_type:nTF {#1}
+ { \@@_replace_normal:N }
+ {
+ \tl_if_head_is_group:nTF {#1}
+ { \@@_replace_group:n }
+ { \@@_replace_space:w }
+ }
+ #1 \q_@@_stop
+ }
+\cs_new:Npn \@@_replace_end:wnn \q_@@_stop #1 #2
+ { \exp_end: {#1} {#2} }
+\cs_new:Npn \@@_flush:nw #1
+ #2 \q_@@_stop #3 #4
+ { \@@_replace_loop:w #2 \q_@@_stop { #3 #1 } {#4} }
+% \end{macrocode}
+%
+% \cs{@@_append_output:nnNwnn} takes three arguments (a parameter
+% number, a parameter name, and a parameter token) and the two output
+% slots as |#5| and |#6|. It appends the parameter token and number
+% to the first output slot, and a definition
+% |\cs_set:cpn {|\cs{c_@@_prefix_tl}~\meta{name}|} {|\meta{number}|}|
+% to the second output slot.
+% \begin{macrocode}
+\cs_new:Npn \@@_append_output:nnNwnn #1 #2 #3
+ #4 \q_@@_stop #5 #6
+ {
+ \@@_replace_loop:w #4 \q_@@_stop
+ { #5 #3#1 }
+ { #6 \cs_set:cpn { \c_@@_prefix_tl #2 } {#1} }
+ }
+% \end{macrocode}
+%
+% This macro doesn't really abort the definition at the time it's
+% called because it's called from within an |f|-expansion context, so
+% an attempt to end that prematurely will hardly end well. Instead
+% it hijacks the process by inserting
+% \cs{@@_skip_to_scan_mark:w} in the second output slot, so that
+% the definition end as soon as the scanning ends.
+% \TODO{Can be simplified further.}
+% \begin{macrocode}
+\cs_new:Npn \@@_abort_definition:w
+ #1 \q_@@_stop #2 #3
+ {
+ \@@_replace_loop:w #1 \q_@@_stop
+ {#2} { #3 \group_end: \@@_skip_to_scan_mark:w }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[EXP]{\@@_replace_normal:N}
+% \begin{macro}[EXP]{\@@_replace_group:n, \@@_flush_group:nnw}
+% \begin{macro}[EXP]{\@@_replace_space:w}
+% Spaces are just passed through: they aren't parameter tokens nor
+% valid delimiters, so need no special treatment.
+%
+% Braced tokens are recursively scanned by \cs{@@_replace_parm:Nn},
+% and the output is flushed inside a pair of braces (explicit catcode
+% $1$ and $2$ tokens are normalised to |{|_$1$ and |}|_$2$,
+% respectively)
+% \TODO{Since \cs{__tl_act:NNNnn} isn't used anymore, this doesn't
+% have to be |f|-expandable, so this restriciton can probably be
+% lifted.}
+%
+% The remaining tokens are examined for their meaning. If the token
+% is the quark \cs{q_@@_mark}, the scanning stops; if the token is a
+% parameter token, what follows is examined with \cs{@@_grab_parm:Nw}
+% to check if a replacement should be done; otherwise it's fluhsed to
+% the output.
+% \begin{macrocode}
+\cs_new:Npn \@@_replace_normal:N #1
+ {
+ \token_if_eq_meaning:NNTF \q_@@_mark #1
+ { \@@_replace_end:wnn }
+ {
+ \token_if_parameter:NTF #1
+ { \@@_grab_parm:Nw }
+ { \@@_flush:nw }
+ {#1}
+ }
+ }
+\cs_new:Npn \@@_replace_group:n #1
+ { \@@_replace_parm:Nn \@@_flush_group:nnw {#1} }
+\cs_new:Npn \@@_flush_group:nnw #1 #2
+ { \@@_flush:nw { {#1} } }
+\exp_last_unbraced:NNo
+\cs_new:Npn \@@_replace_space:w \c_space_tl
+ { \@@_flush:nw { ~ } }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Parsing a parameter}
+%
+% \begin{macro}[EXP]{\@@_grab_parm:Nw}
+% \begin{macro}[EXP]{\@@_grab_parm_aux:NNw, \@@_grab_parm_noop:NNw}
+% \begin{macro}[EXP]{\@@_grab_parm_scan:NNw}
+% \begin{macro}[EXP]{\@@_grab_parm_loop:nw, \@@_grab_parm_end:nw}
+% \begin{macro}[EXP]{
+% \@@_parm_get_normal:nN,
+% \@@_parm_get_group:nn,
+% \@@_parm_get_space:nw
+% }
+% These macros are the final pieces of the parameter replacement
+% routine. \cs{@@_grab_parm:Nw} checks if the next token in the stream
+% is a valid |N|-type. If it is, then \cs{@@_grab_parm_aux:NNw} checks
+% if its character code is equal to \cs{@@_begin_name_token:}, and if
+% it is, then call \cs{@@_grab_parm_scan:NNw} to scan ahead for the
+% named parameter. In all other cases, the tokens grabbed are not
+% named parameters, so they are flushed to the output.
+% \begin{macrocode}
+\cs_new:Npn \@@_grab_parm:Nw #1 #2 \q_@@_stop
+ {
+ \tl_if_head_is_N_type:nTF {#2}
+ { \@@_grab_parm_aux:NNw }
+ { \@@_flush:nw }
+ #1 #2 \q_@@_stop
+ }
+\cs_new:Npn \@@_grab_parm_aux:NNw #1 #2
+ {
+ \exp_args:No \token_if_eq_charcode:NNTF
+ { \@@_begin_name_token: } #2
+ { \@@_grab_parm_scan:NNw }
+ { \@@_grab_parm_noop:NNw }
+ #1 #2
+ }
+% \end{macrocode}
+%
+% Here we have to take care not to flush \cs{q_@@_mark} to the output.
+% \begin{macrocode}
+\cs_new:Npn \@@_grab_parm_noop:NNw #1 #2
+ {
+ \token_if_eq_meaning:NNTF \q_@@_mark #2
+ { \@@_flush:nw { #1 } #2 }
+ { \@@_flush:nw { #1 #2 } }
+ }
+% \end{macrocode}
+%
+% Here's the actual scanning routine. It would be a lot faster to
+% just define a delimiter macro with the right tokens, however this
+% would have two consequences: first, missing delimiters would be
+% rather catastrophic, and second, the catcode of the |end| delimiter
+% would need to match. With a manual scanning, we can kill off those
+% two items at the cost of some performance.
+%
+% The scanning routine is pretty standard: a looping macro, an output
+% slot, the tokens to be scanned, \cs{q_@@_stop} to delimit the whole
+% thing (\cs{q_@@_mark} is redundant here: the one from the main
+% scanning rountine is already in place), and the parameter token
+% safely stored at the end:
+% \begin{macrocode}
+\cs_new:Npn \@@_grab_parm_scan:NNw #1 #2 #3 \q_@@_stop
+ { \@@_grab_parm_loop:nw { } #3 \q_@@_stop {#1} }
+\cs_new:Npn \@@_grab_parm_loop:nw #1 #2 \q_@@_stop
+ {
+ \tl_if_head_is_N_type:nTF {#2}
+ { \@@_parm_get_normal:nN }
+ {
+ \tl_if_head_is_group:nTF {#2}
+ { \@@_parm_get_group:nn }
+ { \@@_parm_get_space:nw }
+ }
+ {#1} #2 \q_@@_stop
+ }
+% \end{macrocode}
+%
+% If the end of the token list was reached (signalled by
+% \cs{q_@@_mark}), the |end| delimiter is missing. If so, raise an
+% error and recover as gracefully as possible. Otherwise, if the
+% current token is the same character as the \cs{@@_end_name_token:},
+% then the scaning is complete.
+% \begin{macrocode}
+\cs_new:Npn \@@_parm_get_normal:nN #1 #2
+ {
+ \token_if_eq_meaning:NNTF \q_@@_mark #2
+ {
+ \msg_expandable_error:nn { namedef } { missing-end }
+ \@@_grab_parm_end:nw {#1} #2
+ }
+ {
+ \exp_args:No \token_if_eq_charcode:NNTF
+ { \@@_end_name_token: } #2
+ { \@@_grab_parm_end:nw {#1} }
+ { \@@_grab_parm_loop:nw {#1#2} }
+ }
+ }
+\cs_new:Npn \@@_parm_get_group:nn #1 #2
+ { \@@_grab_parm_loop:nw { #1{#2} } }
+\cs_new:Npn \@@_parm_get_space:nw #1 ~
+ { \@@_grab_parm_loop:nw { #1~ } }
+\cs_new:Npn \@@_grab_parm_end:nw #1 #2 \q_@@_stop #3
+ { \@@_handle_parameter:nN {#1} #3 #2 \q_@@_stop }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Changing delimiters}
+%
+% \begin{macro}[EXP]{\@@_begin_name_token:, \@@_end_name_token:}
+% These two hold the delimiters for named parameters. They are
+% initialised here so that we can use \cs{named} (just to show off)
+% ahead, and they are redefined every time \cs{NamedDelim} is used.
+% \begin{macrocode}
+\cs_new:Npn \@@_begin_name_token: { [ }
+\cs_new:Npn \@@_end_name_token: { ] }
+% \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\NamedDelim, \globalNamedDelim}
+% \begin{macro}{\@@_named_delim_set:Nnn}
+% \begin{macro}{\@@_check_delimiter:n}
+% At this point everything for the \cs{named} macro is set up,
+% so we can start using it. Now just some syntactic sugar to
+% allow the modification of the named argument delimiters.
+%
+% Both \cs{NamedDelim} and \cs{globalNamedDelim} take two arguments,
+% an initial and final delimiters for the named argument. Both
+% delimters should be single non-control sequence tokens. Some of
+% these restrictions could be lifted, but it's not really necessary
+% because the choice of delimiter should not influence the working of
+% the code, only the readability. A code with |\NamedDelim[]| and
+% |\def\test#[1][#[2]]{[#[1]][#[2]]}| should work without problems;
+% the only restriction is that \cs{@@_end_name_token:} (\emph{i.e.,}
+% the second argument of \cs{NamedDelim}) cannot appear in the
+% parameter name.
+% \begin{macrocode}
+\cs_new_protected:Npn \NamedDelim
+ { \@@_named_delim_set:Nnn \cs_set:Npn }
+\cs_new_protected:Npn \globalNamedDelim
+ { \@@_named_delim_set:Nnn \cs_gset:Npn }
+\named \cs_new_protected:Npn \@@_named_delim_set:Nnn
+ #[def] #[begin] #[end]
+ {
+ \tl_trim_spaces_apply:nN {#[begin]} \@@_check_delimiter:n
+ \tl_trim_spaces_apply:nN {#[end]} \@@_check_delimiter:n
+ #[def] \@@_begin_name_token: {#[begin]}
+ #[def] \@@_end_name_token: {#[end]}
+ \s_@@
+ }
+% \end{macrocode}
+%
+% Here the \meta{token} is checked against a bunch of forbidden cases.
+% \begin{macrocode}
+\named \cs_new_protected:Npn \@@_check_delimiter:n #[token]
+ {
+% \end{macrocode}
+% It can't be empty (nor a space: they were trimmed above):
+% \begin{macrocode}
+ \tl_if_empty:nT {#[token]}
+ {
+ \msg_error:nn { namedef } { blank-delim }
+ \@@_skip_to_scan_mark:w
+ }
+% \end{macrocode}
+% It can't be multiple tokens:
+% \begin{macrocode}
+ \tl_if_single_token:nF {#[token]}
+ {
+ \msg_error:nnn { namedef } { multi-token-delim } {#[token]}
+ \@@_skip_to_scan_mark:w
+ }
+% \end{macrocode}
+% It can't be an implicit begin- or end-group token:
+% \begin{macrocode}
+ \bool_lazy_or:nnT
+ { \token_if_group_begin_p:N #[token] }
+ { \token_if_group_end_p:N #[token] }
+ {
+ \msg_error:nnx { namedef } { group-delim }
+ { \cs_to_str:N #[token] }
+ \@@_skip_to_scan_mark:w
+ }
+% \end{macrocode}
+% It can't be a parameter token:
+% \TODO{Maybe it can, but maybe it will be ambiguous. Must check.}
+% \begin{macrocode}
+ \token_if_parameter:NT #[token]
+ {
+ \msg_error:nnx { namedef } { param-delim }
+ { \cs_to_str:N #[token] }
+ \@@_skip_to_scan_mark:w
+ }
+% \end{macrocode}
+% It can't be a control sequence:
+% \TODO{It probably can, but I'm not sure I want to allow this.}
+% \begin{macrocode}
+ \token_if_cs:NT #[token]
+ {
+ \msg_error:nnx { namedef } { macro-delim }
+ { \c_backslash_str \cs_to_str:N #[token] }
+ \@@_skip_to_scan_mark:w
+ }
+ }
+% \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \subsection{Messages}
+%
+% Now we define the messages used throughout the package.
+%
+% \begin{macrocode}
+\msg_new:nnn { namedef } { repeated-parm }
+ {
+ Parameter~\iow_char:N\#[#1]~duplicated~in~
+ definition~of~\l_@@_macro_tl.
+ }
+\msg_new:nnn { namedef } { unknown-parm }
+ {
+ Unknown~parameter~\iow_char:N\#[#1]~in~
+ definition~of~\l_@@_macro_tl.
+ }
+\msg_new:nnn { namedef } { multi-token-delim }
+ {
+ Invalid~\iow_char:N\\named~parameter~delimiter~`#1'.~
+ Delimiters~for~named~parameters~must~be~single~tokens.
+ }
+\msg_new:nnn { namedef } { macro-delim }
+ {
+ Invalid~\iow_char:N\\named~parameter~delimiter~`#1'.~
+ Delimiters~for~named~parameters~can't~be~control~sequence~nor~
+ active~characters.
+ }
+\msg_new:nnn { namedef } { group-delim }
+ {
+ Invalid~\iow_char:N\\named~parameter~delimiter~`\iow_char:N\\#1'.~
+ Delimiters~for~named~parameters~can't~be~
+ begin-/end-group~character~tokens.
+ }
+\msg_new:nnn { namedef } { blank-delim }
+ {
+ Invalid~\iow_char:N\\named~parameter~delimiter.~
+ Delimiters~for~named~parameters~can't~be~empty~nor~space~tokens.
+ }
+\msg_new:nnn { namedef } { param-delim }
+ {
+ Invalid~\iow_char:N\\named~parameter~delimiter.~
+ Delimiters~for~named~parameters~can't~be~parameter~tokens.
+ }
+\msg_new:nnn { namedef } { missing-end }
+ {
+ Missing~\@@_end_name_token:\iow_char:N\ inserted~in~
+ definition~of~\l_@@_macro_tl.
+ }
+% \end{macrocode}
+%
+% Now execute the end package hook (in \LaTeX{} it is
+% \cs{prg_do_nothing:}, but in plain \TeX{} it does \cs{ExplSyntaxOff}).
+%
+% \begin{macrocode}
+\@@_end_package_hook:
+% \end{macrocode}
+%
+% \iffalse
+%</package>
+% \fi
+%
+% \end{implementation}
+%
+%^^A \par\CodedocExplainEXP
+%^^A \par\CodedocExplainREXP
+%^^A \par\CodedocExplainTF
+%
+% \PrintIndex
+%
+\endinput
diff --git a/Master/texmf-dist/source/generic/namedef/namedef.ins b/Master/texmf-dist/source/generic/namedef/namedef.ins
new file mode 100644
index 00000000000..50806470e1d
--- /dev/null
+++ b/Master/texmf-dist/source/generic/namedef/namedef.ins
@@ -0,0 +1,90 @@
+%%
+%% Copyright (C) 2019--2020
+%% by Phelype Oleinik <phelype.oleinik@latex-project.org>
+%%
+%% This work may be distributed and/or modified under the conditions of
+%% the LaTeX Project Public License, either version 1.3c of this license
+%% or (at your option) any later version. The latest version of this
+%% license is in
+%%
+%% http://www.latex-project.org/lppl.txt
+%%
+%% and version 1.3c or later is part of all distributions of LaTeX
+%% version 2005/12/01 or later.
+%%
+%% This work is "maintained" (as per the LPPL maintenance status)
+%% by Phelype Oleinik.
+%%
+\def\projectname{namedef}%
+\def\nameofplainTeX{plain}%
+\def\mainext{sty}
+\ifx\fmtname\nameofplainTeX
+\else
+ \expandafter\begingroup
+\fi
+\input l3docstrip.tex
+\keepsilent
+\askforoverwritefalse
+
+\preamble
+
+This is a generated file.
+
+Copyright 2019--2020 Phelype Oleinik /phelype.oleinik@latex-project.org/
+
+This work may be distributed and/or modified under the conditions of the
+LaTeX Project Public License, either version 1.3c of this license or (at
+your option) any later version. The latest version of this license is in
+
+ http://www.latex-project.org/lppl.txt
+
+and version 1.3c or later is part of all distributions of LaTeX version
+2005/12/01 or later.
+
+\endpreamble
+
+\postamble
+
+This work is "maintained" (as per the LPPL maintenance status)
+by Phelype Oleinik.
+
+This work consists of the files \projectname.dtx, and
+ \projectname.ins,
+and the derived files \projectname.\mainext,
+ \projectname.pdf,
+ README.md, and
+ README.txt.%
+
+\endpostamble
+
+\generate
+ {
+ \file{\projectname.\mainext}
+ {
+ \from{\projectname.dtx}{package}
+ }
+ }
+
+\Msg{*********************************************************}
+\Msg{*}
+\Msg{* To finish the installation you have to move the}
+\Msg{* following file into a directory searched by TeX:}
+\Msg{*}
+\Msg{* \space\space \projectname.\mainext}
+\Msg{*}
+\ifx\fmtname\nameofplainTeX
+ \Msg{* To produce the documentation run the file \projectname.dtx}
+ \Msg{* through LaTeX.}
+ \Msg{*}
+\fi
+\Msg{* Happy TeXing!}
+\Msg{*}
+\Msg{*********************************************************}
+
+\ifx\fmtname\nameofplainTeX
+ \expandafter\endbatchfile
+\else
+ \expandafter\endgroup
+\fi
+
+\input{\projectname.dtx}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-13 08:22:10 +0000