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diff --git a/macros/latex/contrib/l3kernel/l3expan.dtx b/macros/latex/contrib/l3kernel/l3expan.dtx deleted file mode 100644 index 7e507b7598..0000000000 --- a/macros/latex/contrib/l3kernel/l3expan.dtx +++ /dev/null @@ -1,2398 +0,0 @@ -% \iffalse meta-comment -% -%% File: l3expan.dtx -% -% Copyright (C) 1990-2024 The LaTeX Project -% -% It may be distributed and/or modified under the conditions of the -% LaTeX Project Public License (LPPL), either version 1.3c of this -% license or (at your option) any later version. The latest version -% of this license is in the file -% -% https://www.latex-project.org/lppl.txt -% -% This file is part of the "l3kernel bundle" (The Work in LPPL) -% and all files in that bundle must be distributed together. -% -% ----------------------------------------------------------------------- -% -% The development version of the bundle can be found at -% -% https://github.com/latex3/latex3 -% -% for those people who are interested. -% -%<*driver> -\documentclass[full,kernel]{l3doc} -\begin{document} - \DocInput{\jobname.dtx} -\end{document} -%</driver> -% \fi -% -% \title{^^A -% The \pkg{l3expan} module\\ Argument expansion^^A -% } -% -% \author{^^A -% The \LaTeX{} Project\thanks -% {^^A -% E-mail: -% \href{mailto:latex-team@latex-project.org} -% {latex-team@latex-project.org}^^A -% }^^A -% } -% -% \date{Released 2024-03-14} -% -% \maketitle -% -% \begin{documentation} -% -% This module provides generic methods for expanding \TeX{} arguments in a -% systematic manner. The functions in this module all have prefix |exp|. -% -% Not all possible variations are implemented for every base -% function. Instead only those that are used within the \LaTeX3 kernel -% or otherwise seem to be of general interest are implemented. -% Consult the module description to find out which functions are -% actually defined. The next section explains how to define missing -% variants. -% -% \section{Defining new variants} -% \label{sec:l3expan:defining-variants} -% -% The definition of variant forms for base functions may be necessary -% when writing new functions or when applying a kernel function in a -% situation that we haven't thought of before. -% -% Internally preprocessing of arguments is done with functions of the form -% \cs[no-index]{exp_\ldots{}}. They all look alike, an example would be -% \cs{exp_args:NNo}. This function has three arguments, the first and the -% second are a single tokens, while the third argument should be given -% in braces. Applying \cs{exp_args:NNo} expands the content of third -% argument once before any expansion of the first and second arguments. -% If \cs{seq_gpush:No} was not defined it could be coded in the following way: -% \begin{verbatim} -% \exp_args:NNo \seq_gpush:Nn -% \g_file_name_stack -% { \l_tmpa_tl } -% \end{verbatim} -% In other words, the first argument to \cs{exp_args:NNo} is the base -% function and the other arguments are preprocessed and then passed to -% this base function. In the example the first argument to the base -% function should be a single token which is left unchanged while the -% second argument is expanded once. From this example we can also see -% how the variants are defined. They just expand into the appropriate -% |\exp_| function followed by the desired base function, \emph{e.g.} -% \begin{quote} -% |\cs_generate_variant:Nn \seq_gpush:Nn { No } | -% \end{quote} -% results in the definition of |\seq_gpush:No| -% \begin{quote} -% |\cs_new:Npn \seq_gpush:No { \exp_args:NNo \seq_gpush:Nn }| -% \end{quote} -% Providing variants in this way in style files is safe as the -% \cs{cs_generate_variant:Nn} function will only create new definitions if -% there is not already one available. Therefore adding -% such definition to later releases of the kernel will not make such -% style files obsolete. -% -% The steps above may be automated by using the function -% \cs{cs_generate_variant:Nn}, described next. -% -% \section{Methods for defining variants} -% \label{sec:l3expan:variants-method} -% -% We recall the set of available argument specifiers. -% \begin{itemize} -% \item |N|~is used for single-token arguments while |c|~constructs a -% control sequence from its name and passes it to a parent function as -% an |N|-type argument. -% \item Many argument types extract or expand some tokens and provide it -% as an |n|-type argument, namely a braced multiple-token argument: -% |V|~extracts the value of a variable, |v|~extracts the value from -% the name of a variable, |n|~uses the argument as it is, |o|~expands -% once, |f|~expands fully the front of the token list, |e| and -% |x|~expand fully all tokens (differences are explained later). -% \item A few odd argument types remain: |T|~and |F|~for conditional -% processing, otherwise identical to |n|-type arguments, -% |p|~for the parameter text -% in definitions, |w|~for arguments with a specific syntax, and |D|~to -% denote primitives that should not be used directly. -% \end{itemize} -% -% \begin{function}[updated = 2017-11-28] -% {\cs_generate_variant:Nn, \cs_generate_variant:cn} -% \begin{syntax} -% \cs{cs_generate_variant:Nn} \meta{parent control sequence} \Arg{variant argument specifiers} -% \end{syntax} -% This function is used to define argument-specifier variants of the -% \meta{parent control sequence} for \LaTeX3 code-level macros. The -% \meta{parent control sequence} is first separated into the -% \meta{base name} and \meta{original argument specifier}. The -% comma-separated list of \meta{variant argument specifiers} is -% then used to define variants of the -% \meta{original argument specifier} if these are not already -% defined; entries which correspond to existing functions are silently -% ingored. For each \meta{variant} given, a function is created -% that expands its arguments as detailed and passes them -% to the \meta{parent control sequence}. So for example -% \begin{verbatim} -% \cs_set:Npn \foo:Nn #1#2 { code here } -% \cs_generate_variant:Nn \foo:Nn { c } -% \end{verbatim} -% creates a new function |\foo:cn| which expands its first -% argument into a control sequence name and passes the result to -% |\foo:Nn|. Similarly -% \begin{verbatim} -% \cs_generate_variant:Nn \foo:Nn { NV , cV } -% \end{verbatim} -% generates the functions |\foo:NV| and |\foo:cV| in the same -% way. The \cs{cs_generate_variant:Nn} function should only be applied if -% the \meta{parent control sequence} is already defined. (This is only -% enforced if debugging support \texttt{check-declarations} is enabled.) -% If the \meta{parent -% control sequence} is protected or if the \meta{variant} involves any -% |x|~argument, then the \meta{variant control sequence} is also -% protected. The \meta{variant} is created globally, as is any -% \cs[no-index]{exp_args:N\meta{variant}} function needed to carry out the -% expansion. There is no need to re-apply \cs{cs_generate_variant:Nn} after -% changing the definition of the parent function: the variant will always -% use the current definition of the parent. Providing variants repeatedly is -% safe as \cs{cs_generate_variant:Nn} will only create new definitions if -% there is not already one available. -% -% Only |n|~and |N| arguments can be changed to other types. The only -% allowed changes are -% \begin{itemize} -% \item |c|~variant of an |N|~parent; -% \item |o|, |V|, |v|, |f|, |e|, or~|x| variant of an |n|~parent; -% \item |N|, |n|, |T|, |F|, or |p| argument unchanged. -% \end{itemize} -% This means the \meta{parent} of a \meta{variant} form is always -% unambiguous, even in cases where both an |n|-type parent and an -% |N|-type parent exist, such as for \cs{tl_count:n} and -% \cs{tl_count:N}. -% -% When creating variants for conditional functions, -% \cs{prg_generate_conditional_variant:Nnn} provides a convenient way -% of handling the related function set. -% -% For backward compatibility it is currently possible to make |n|, -% |o|, |V|, |v|, |f|, |e|, or |x|-type variants of an |N|-type argument or -% |N| or |c|-type variants of an |n|-type argument. Both are -% deprecated. The first because passing more than one token to an -% |N|-type argument will typically break the parent function's code. -% The second because programmers who use that most often want to -% access the value of a variable given its name, hence should use a -% |V|-type or |v|-type variant instead of |c|-type. In those cases, -% using the lower-level \cs{exp_args:No} or \cs{exp_args:Nc} -% functions explicitly is preferred to defining confusing variants. -% \end{function} -% -% \begin{function}[added = 2018-04-04, updated = 2019-02-08] -% {\exp_args_generate:n} -% \begin{syntax} -% \cs{exp_args_generate:n} \Arg{variant argument specifiers} -% \end{syntax} -% Defines \cs[no-index]{exp_args:N\meta{variant}} functions for each -% \meta{variant} given in the comma list \Arg{variant argument -% specifiers}. Each \meta{variant} should consist of the letters |N|, -% |c|, |n|, |V|, |v|, |o|, |f|, |e|, |x|, |p| and the resulting function is -% protected if the letter |x| appears in the \meta{variant}. This is -% only useful for cases where \cs{cs_generate_variant:Nn} is not -% applicable. -% \end{function} -% -% \section{Introducing the variants} -% -% The |V| type returns the value of a register, which can be one of -% |tl|, |clist|, |int|, |skip|, |dim|, |muskip|, or built-in \TeX{} -% registers. The |v| type is the same except it first creates a -% control sequence out of its argument before returning the -% value. -% -% In general, the programmer should not need to be concerned with -% expansion control. When simply using the content of a variable, -% functions with a |V| specifier should be used. For those referred to by -% (cs)name, the |v| specifier is available for the same purpose. Only when -% specific expansion steps are needed, such as when using delimited -% arguments, should the lower-level functions with |o| specifiers be employed. -% -% The |e| type expands all tokens fully, starting from the first. More -% precisely the expansion is identical to that of \TeX{}'s \tn{message} -% (in particular |#| needs not be doubled). It relies on the -% primitive \tn{expanded} hence is fast. -% -% The |x| type expands all tokens fully, starting from the first. In -% contrast to |e|, all macro parameter characters |#| must be doubled, -% and omitting this leads to low-level errors. In addition this type of -% expansion is not expandable, namely functions that have |x| in their -% signature do not themselves expand when appearing inside |e| or |x| -% expansion. -% -% The |f| type is so special that it deserves an example. It is -% typically used in contexts where only expandable commands are allowed. -% Then |x|-expansion cannot be used, and |f|-expansion provides an -% alternative that expands the front of the token list -% as much as can be done in such contexts. For -% instance, say that we want to evaluate the integer expression $3 + 4$ -% and pass the result $7$ as an argument to an expandable function -% |\example:n|. For this, one should define a variant using -% \cs{cs_generate_variant:Nn} |\example:n| |{| |f| |}|, then do -% \begin{quote} -% |\example:f { \int_eval:n { 3 + 4 } }| -% \end{quote} -% Note that |x|-expansion would also expand \cs{int_eval:n} fully to its -% result~$7$, but the variant |\example:x| cannot be expandable. Note -% also that |o|-expansion would not expand \cs{int_eval:n} fully to its -% result since that function requires several expansions. Besides the -% fact that |x|-expansion is protected rather than expandable, another -% difference between |f|-expansion and |x|-expansion is that -% |f|-expansion expands tokens from the beginning and stops as soon as a -% non-expandable token is encountered, while |x|-expansion continues -% expanding further tokens. Thus, for instance -% \begin{quote} -% |\example:f { \int_eval:n { 1 + 2 } , \int_eval:n { 3 + 4 } }| -% \end{quote} -% results in the call -% \begin{quote} -% |\example:n { 3 , \int_eval:n { 3 + 4 } }| -% \end{quote} -% while using |\example:x| or |\example:e| instead results in -% \begin{quote} -% |\example:n { 3 , 7 }| -% \end{quote} -% at the cost of being protected for |x|-type. -% If you use |f| type expansion in conditional processing then -% you should stick to using |TF| type functions only as the expansion -% does not finish any |\if... \fi:| itself! -% -% It is important to note that both \texttt{f}- and \texttt{o}-type -% expansion are concerned with the expansion of tokens from left to -% right in their arguments. In particular, \texttt{o}-type expansion -% applies to the first \emph{token} in the argument it receives: it -% is conceptually similar to -% \begin{verbatim} -% \exp_after:wN <base function> \exp_after:wN { <argument> } -% \end{verbatim} -% At the same time, \texttt{f}-type expansion stops at the \emph{first} -% non-expandable token. This means for example that both -% \begin{verbatim} -% \tl_set:No \l_tmpa_tl { { \g_tmpb_tl } } -% \end{verbatim} -% and -% \begin{verbatim} -% \tl_set:Nf \l_tmpa_tl { { \g_tmpb_tl } } -% \end{verbatim} -% leave |\g_tmpb_tl| unchanged: |{| is the first token in the -% argument and is non-expandable. -% -% It is usually best to keep the following in mind when using variant -% forms. -% \begin{itemize} -% \item -% Variants with |x|-type arguments (that are fully expanded before -% being passed to the |n|-type base function) are never expandable -% even when the base function is. Such variants cannot work -% correctly in arguments that are themselves subject to expansion. -% Consider using |f| or |e| expansion. -% \item -% In contrast, |e|~expansion (full expansion, almost like~|x| except -% for the treatment of~|#|) does not prevent variants from being -% expandable (if the base function is). -% \item -% Finally |f|~expansion only expands the front of the token list, -% stopping at the first non-expandable token. This may fail to -% fully expand the argument. -% \end{itemize} -% -% When speed is essential (for functions that do very little work and -% whose variants are used numerous times in a document) the following -% considerations apply because the speed of internal functions that -% expand the arguments of a base function depend on what needs doing -% with each argument and where this happens in the list of arguments: -% \begin{itemize} -% \item for fastest processing any |c|-type arguments should come first -% followed by all other modified arguments; -% \item unchanged |N|-type args that appear before modified ones have -% a small performance hit; -% \item unchanged |n|-type args that appear before modified ones have -% a relative larger performance hit. -% \end{itemize} -% -% \section{Manipulating the first argument} -% -% These functions are described in detail: expansion of multiple tokens follows -% the same rules but is described in a shorter fashion. -% -% \begin{function}[EXP]{\exp_args:Nc, \exp_args:cc} -% \begin{syntax} -% \cs{exp_args:Nc} \meta{function} \Arg{tokens} -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}). The \meta{tokens} are expanded until only characters -% remain, and are then turned into a control sequence. -% The result is inserted into the input stream \emph{after} reinsertion -% of the \meta{function}. Thus the \meta{function} may take more than -% one argument: all others are left unchanged. -% -% The |:cc| variant constructs the \meta{function} name in the same -% manner as described for the \meta{tokens}. -% \end{function} -% -% \begin{function}[EXP]{\exp_args:No} -% \begin{syntax} -% \cs{exp_args:No} \meta{function} \Arg{tokens} ... -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}). The \meta{tokens} are expanded once, and the result -% is inserted in braces into the input stream \emph{after} reinsertion -% of the \meta{function}. Thus the \meta{function} may take more than -% one argument: all others are left unchanged. -% \end{function} -% -% \begin{function}[EXP]{\exp_args:NV} -% \begin{syntax} -% \cs{exp_args:NV} \meta{function} \meta{variable} -% \end{syntax} -% This function absorbs two arguments (the names of the \meta{function} and -% the \meta{variable}). The content of the \meta{variable} are recovered -% and placed inside braces into the input stream \emph{after} reinsertion -% of the \meta{function}. Thus the \meta{function} may take more than -% one argument: all others are left unchanged. -% \end{function} -% -% \begin{function}[EXP]{\exp_args:Nv} -% \begin{syntax} -% \cs{exp_args:Nv} \meta{function} \Arg{tokens} -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}). The \meta{tokens} are expanded until only characters -% remain, and are then turned into a control sequence. -% This control sequence should -% be the name of a \meta{variable}. The content of the \meta{variable} are -% recovered and placed inside braces into the input stream \emph{after} -% reinsertion of the \meta{function}. Thus the \meta{function} may take more -% than one argument: all others are left unchanged. -% \end{function} -% -% \begin{function}[EXP, added = 2018-05-15]{\exp_args:Ne} -% \begin{syntax} -% \cs{exp_args:Ne} \meta{function} \Arg{tokens} -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}) and exhaustively expands the \meta{tokens}. -% The result is inserted in braces into the input stream -% \emph{after} reinsertion of the \meta{function}. -% Thus the \meta{function} may take more -% than one argument: all others are left unchanged. -% \end{function} -% -% \begin{function}[EXP]{\exp_args:Nf} -% \begin{syntax} -% \cs{exp_args:Nf} \meta{function} \Arg{tokens} -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}). The \meta{tokens} are fully expanded until the -% first non-expandable token is found (if that is a space it is -% removed), and the result -% is inserted in braces into the input stream \emph{after} reinsertion -% of the \meta{function}. Thus the \meta{function} may take more than -% one argument: all others are left unchanged. -% \end{function} -% -% \begin{function}{\exp_args:Nx} -% \begin{syntax} -% \cs{exp_args:Nx} \meta{function} \Arg{tokens} -% \end{syntax} -% This function absorbs two arguments (the \meta{function} name and -% the \meta{tokens}) and exhaustively expands the \meta{tokens}. -% The result is inserted in braces into the input stream -% \emph{after} reinsertion of the \meta{function}. -% Thus the \meta{function} may take more -% than one argument: all others are left unchanged. -% \end{function} -% -% \section{Manipulating two arguments} -% -% \begin{function}[EXP, updated = 2018-05-15] -% { -% \exp_args:NNc, -% \exp_args:NNo, -% \exp_args:NNV, -% \exp_args:NNv, -% \exp_args:NNe, -% \exp_args:NNf, -% \exp_args:Ncc, -% \exp_args:Nco, -% \exp_args:NcV, -% \exp_args:Ncv, -% \exp_args:Ncf, -% \exp_args:NVV -% } -% \begin{syntax} -% \cs{exp_args:NNc} \meta{token_1} \meta{token_2} \Arg{tokens} -% \end{syntax} -% These optimized functions absorb three arguments and expand the second and -% third as detailed by their argument specifier. The first argument -% of the function is then the next item on the input stream, followed -% by the expansion of the second and third arguments. -% \end{function} -% -% \begin{function}[EXP, updated = 2018-05-15] -% { -% \exp_args:Nnc, -% \exp_args:Nno, -% \exp_args:NnV, -% \exp_args:Nnv, -% \exp_args:Nne, -% \exp_args:Nnf, -% \exp_args:Noc, -% \exp_args:Noo, -% \exp_args:Nof, -% \exp_args:NVo, -% \exp_args:Nfo, -% \exp_args:Nff, -% \exp_args:Nee, -% } -% \begin{syntax} -% \cs{exp_args:Noo} \meta{token} \Arg{tokens_1} \Arg{tokens_2} -% \end{syntax} -% These functions absorb three arguments and expand the second and -% third as detailed by their argument specifier. The first argument -% of the function is then the next item on the input stream, followed -% by the expansion of the second and third arguments. -% \end{function} -% -% \begin{function} -% { -% \exp_args:NNx, -% \exp_args:Ncx, -% \exp_args:Nnx, -% \exp_args:Nox, -% \exp_args:Nxo, -% \exp_args:Nxx -% } -% \begin{syntax} -% \cs{exp_args:NNx} \meta{token_1} \meta{token_2} \Arg{tokens} -% \end{syntax} -% These functions absorb three arguments and expand the second and -% third as detailed by their argument specifier. The first argument -% of the function is then the next item on the input stream, followed -% by the expansion of the second and third arguments. These functions -% are not expandable due to their |x|-type argument. -% \end{function} -% -% \section{Manipulating three arguments} -% -% \begin{function}[EXP] -% { -% \exp_args:NNNo, -% \exp_args:NNNV, -% \exp_args:NNNv, -% \exp_args:NNNe, -% \exp_args:Nccc, -% \exp_args:NcNc, -% \exp_args:NcNo, -% \exp_args:Ncco -% } -% \begin{syntax} -% \cs{exp_args:NNNo} \meta{token_1} \meta{token_2} \meta{token_3} \Arg{tokens} -% \end{syntax} -% These optimized functions absorb four arguments and expand the second, third -% and fourth as detailed by their argument specifier. The first -% argument of the function is then the next item on the input stream, -% followed by the expansion of the second argument, \emph{etc}. -% \end{function} -% -% \begin{function}[EXP] -% { -% \exp_args:NNcf, -% \exp_args:NNno, -% \exp_args:NNnV, -% \exp_args:NNoo, -% \exp_args:NNVV, -% \exp_args:Ncno, -% \exp_args:NcnV, -% \exp_args:Ncoo, -% \exp_args:NcVV, -% \exp_args:Nnnc, -% \exp_args:Nnno, -% \exp_args:Nnnf, -% \exp_args:Nnff, -% \exp_args:Nooo, -% \exp_args:Noof, -% \exp_args:Nffo, -% \exp_args:Neee -% } -% \begin{syntax} -% \cs{exp_args:NNoo} \meta{token_1} \meta{token_2} \Arg{token_3} \Arg{tokens} -% \end{syntax} -% These functions absorb four arguments and expand the second, third -% and fourth as detailed by their argument specifier. The first -% argument of the function is then the next item on the input stream, -% followed by the expansion of the second argument, \emph{etc}. -% \end{function} -% -% \begin{function}[added = 2015-08-12] -% { -% \exp_args:NNNx, -% \exp_args:NNnx, -% \exp_args:NNox, -% \exp_args:Nccx, -% \exp_args:Ncnx, -% \exp_args:Nnnx, -% \exp_args:Nnox, -% \exp_args:Noox, -% } -% \begin{syntax} -% \cs{exp_args:NNnx} \meta{token_1} \meta{token_2} \Arg{tokens_1} \Arg{tokens_2} -% \end{syntax} -% These functions absorb four arguments and expand the second, third -% and fourth as detailed by their argument specifier. The first -% argument of the function is then the next item on the input stream, -% followed by the expansion of the second argument, \emph{etc.} -% \end{function} -% -% \section{Unbraced expansion} -% -% \begin{function}[EXP, updated = 2018-05-15] -% { -% \exp_last_unbraced:No, -% \exp_last_unbraced:NV, -% \exp_last_unbraced:Nv, -% \exp_last_unbraced:Ne, -% \exp_last_unbraced:Nf, -% \exp_last_unbraced:NNo, -% \exp_last_unbraced:NNV, -% \exp_last_unbraced:NNf, -% \exp_last_unbraced:Nco, -% \exp_last_unbraced:NcV, -% \exp_last_unbraced:Nno, -% \exp_last_unbraced:Nnf, -% \exp_last_unbraced:Noo, -% \exp_last_unbraced:Nfo, -% \exp_last_unbraced:NNNo, -% \exp_last_unbraced:NNNV, -% \exp_last_unbraced:NNNf, -% \exp_last_unbraced:NnNo, -% \exp_last_unbraced:NNNNo, -% \exp_last_unbraced:NNNNf, -% } -% \begin{syntax} -% \cs{exp_last_unbraced:Nno} \meta{token} \Arg{tokens_1} \Arg{tokens_2} -% \end{syntax} -% These functions absorb the number of arguments given by their -% specification, carry out the expansion -% indicated and leave the results in the input stream, with the -% last argument not surrounded by the usual braces. -% Of these, the |:Nno|, |:Noo|, |:Nfo| and |:NnNo| -% variants need slower processing. -% \begin{texnote} -% As an optimization, the last argument is unbraced by some -% of those functions before expansion. This can cause problems -% if the argument is empty: for instance, -% \cs{exp_last_unbraced:Nf} |\foo_bar:w| |{ }| \cs{q_stop} -% leads to an infinite loop, as the quark is \texttt{f}-expanded. -% \end{texnote} -% \end{function} -% -% \begin{function}{\exp_last_unbraced:Nx} -% \begin{syntax} -% \cs{exp_last_unbraced:Nx} \meta{function} \Arg{tokens} -% \end{syntax} -% This function fully expands the \meta{tokens} and leaves the result -% in the input stream after reinsertion of the \meta{function}. -% This function is not expandable. -% \end{function} -% -% \begin{function}[EXP]{\exp_last_two_unbraced:Noo} -% \begin{syntax} -% \cs{exp_last_two_unbraced:Noo} \meta{token} \Arg{tokens_1} \Arg{tokens_2} -% \end{syntax} -% This function absorbs three arguments and expands the second and third -% once. The first argument of the function is then the next item on the -% input stream, followed by the expansion of the second and third arguments, -% which are not wrapped in braces. -% This function needs special (slower) processing. -% \end{function} -% -% \begin{function}[EXP]{\exp_after:wN} -% \begin{syntax} -% \cs{exp_after:wN} \meta{token_1} \meta{token_2} -% \end{syntax} -% Carries out a single expansion of \meta{token_2} (which may consume -% arguments) prior to the expansion of \meta{token_1}. If \meta{token_2} has -% no expansion (for example, if it is a character) then it is left -% unchanged. It is important to notice that \meta{token_1} may be -% \emph{any} single token, including group-opening and -closing -% tokens (|{| or |}| assuming normal \TeX{} category codes). Unless -% specifically required this should be avoided: expansion should be carried out using an -% appropriate argument specifier variant or the appropriate -% \cs[no-index]{exp_args:N\meta{variant}} function. -% \begin{texnote} -% This is the \TeX{} primitive \tn{expandafter}. -% \end{texnote} -% \end{function} -% -% -% \section{Preventing expansion} -% -% Despite the fact that the following functions are all about preventing -% expansion, they're designed to be used in an expandable context and hence -% are all marked as being `expandable' since they themselves disappear -% after the expansion has completed. -% -% \begin{function}[EXP]{\exp_not:N} -% \begin{syntax} -% \cs{exp_not:N} \meta{token} -% \end{syntax} -% Prevents expansion of the \meta{token} in a context where it would -% otherwise be expanded, for example an |e|-type or |x|-type argument or -% the first token in an |o|-type or |f|-type argument. -% \begin{texnote} -% This is the \TeX{} primitive \tn{noexpand}. It only prevents -% expansion. At the beginning of an |f|-type argument, a space -% \meta{token} is removed even if it appears as \cs{exp_not:N} -% \cs{c_space_token}. In an |e|-expanding definition -% (\cs{cs_new:Npe}), a macro parameter introduces an argument even -% if it appears as \cs{exp_not:N} |#| |1|. This differs from -% \cs{exp_not:n}. -% \end{texnote} -% \end{function} -% -% \begin{function}[EXP]{\exp_not:c} -% \begin{syntax} -% \cs{exp_not:c} \Arg{tokens} -% \end{syntax} -% Expands the \meta{tokens} until only characters remain, and then -% converts this into a control sequence. -% Further expansion of this control sequence is then inhibited using -% \cs{exp_not:N}. -% \end{function} -% -% \begin{function}[EXP]{\exp_not:n} -% \begin{syntax} -% \cs{exp_not:n} \Arg{tokens} -% \end{syntax} -% Prevents expansion of the \meta{tokens} in an |e|-type or |x|-type argument. -% In all other cases the \meta{tokens} continue to be expanded, for -% example in the input stream or in other types of arguments such as -% \texttt{c}, \texttt{f}, \texttt{v}. The argument of \cs{exp_not:n} -% \emph{must} be surrounded by braces. -% \begin{texnote} -% This is the \eTeX{} primitive \tn{unexpanded}. In an -% |e|-expanding definition (\cs{cs_new:Npe}), \cs{exp_not:n}~|{#1}| -% is equivalent to |##1| rather than to~|#1|, namely it inserts the -% two characters |#| and~|1|, and -% \cs{exp_not:n}~|{#}| is equivalent to |#|, namely it inserts the -% character~|#|. -% \end{texnote} -% \end{function} -% -% \begin{function}[EXP]{\exp_not:o} -% \begin{syntax} -% \cs{exp_not:o} \Arg{tokens} -% \end{syntax} -% Expands the \meta{tokens} once, then prevents any further expansion -% in |e|-type or |x|-type arguments using \cs{exp_not:n}. -% \end{function} -% -% \begin{function}[EXP]{\exp_not:V} -% \begin{syntax} -% \cs{exp_not:V} \meta{variable} -% \end{syntax} -% Recovers the content of the \meta{variable}, then prevents expansion -% of this material in |e|-type or |x|-type arguments using \cs{exp_not:n}. -% \end{function} -% -% \begin{function}[EXP]{\exp_not:v} -% \begin{syntax} -% \cs{exp_not:v} \Arg{tokens} -% \end{syntax} -% Expands the \meta{tokens} until only characters remains, and then -% converts this into a control sequence which should be a \meta{variable} -% name. -% The content of the \meta{variable} is recovered, and further -% expansion in |e|-type or |x|-type arguments is prevented using \cs{exp_not:n}. -% \end{function} -% -% \begin{function}[EXP]{\exp_not:e} -% \begin{syntax} -% \cs{exp_not:e} \Arg{tokens} -% \end{syntax} -% Expands \meta{tokens} exhaustively, then protects the result of the -% expansion (including any tokens which were not expanded) from -% further expansion in |e|-type or |x|-type arguments using \cs{exp_not:n}. -% This is very rarely useful but is provided for consistency. -% \end{function} -% -% \begin{function}[EXP]{\exp_not:f} -% \begin{syntax} -% \cs{exp_not:f} \Arg{tokens} -% \end{syntax} -% Expands \meta{tokens} fully until the first unexpandable token is -% found (if it is a space it is removed). Expansion then stops, and -% the result of the expansion (including any tokens which were not -% expanded) is protected from further expansion in |e|-type or |x|-type arguments -% using \cs{exp_not:n}. -% \end{function} -% -% \begin{function}[updated = 2011-06-03, EXP]{\exp_stop_f:} -% \begin{syntax} -% |\foo_bar:f| \{ \meta{tokens} \cs{exp_stop_f:} \meta{more tokens} \} -% \end{syntax} -% This function terminates an \texttt{f}-type expansion. Thus if -% a function |\foo_bar:f| starts an \texttt{f}-type expansion -% and all of \meta{tokens} are expandable \cs{exp_stop_f:} -% terminates the expansion of tokens even if \meta{more tokens} -% are also expandable. The function itself is an implicit space -% token. Inside an \texttt{e}-type or \texttt{x}-type expansion, it retains its -% form, but when typeset it produces the underlying space (\verb*| |). -% \end{function} -% -% -% \section{Controlled expansion} -% -% The \pkg{expl3} language makes all efforts to hide the complexity of -% \TeX{} expansion from the programmer by providing concepts that -% evaluate/expand arguments of functions prior to calling the \enquote{base} -% functions. Thus, instead of using many \tn{expandafter} calls and -% other trickery it is usually a matter of choosing the right variant -% of a function to achieve a desired result. -% -% Of course, deep down \TeX{} is using expansion as always and there -% are cases where a programmer needs to control that expansion -% directly; typical situations are basic data manipulation tools. This -% section documents the functions for that level. These -% commands are used throughout the kernel code, but we hope that outside -% the kernel there will be little need to resort to them. Instead the -% argument manipulation methods document above should usually be sufficient. -% -% While \cs{exp_after:wN} expands one token (out of order) it is -% sometimes necessary to expand several tokens in one go. The next set -% of commands provide this functionality. Be aware that it is -% absolutely required that the programmer has full control over the -% tokens to be expanded, i.e., it is not possible to use these -% functions to expand unknown input as part of -% \meta{expandable-tokens} as that will break badly if unexpandable -% tokens are encountered in that place! -% -% \begin{function}[added=2015-08-23,EXP] -% { -% \exp:w , -% \exp_end: -% } -% \begin{syntax} -% \cs{exp:w} \meta{expandable tokens} \cs{exp_end:} \\ -% \end{syntax} -% Expands \meta{expandable-tokens} until reaching \cs{exp_end:} at -% which point expansion stops. -% The full expansion of \meta{expandable tokens} has to be empty. -% If any token in \meta{expandable tokens} or any token generated by -% expanding the tokens therein is not expandable the expansion will end -% prematurely and as a result \cs{exp_end:} will be misinterpreted -% later on.\footnotemark -% -% In typical use cases the \cs{exp_end:} is hidden somewhere -% in the replacement text of \meta{expandable-tokens} rather than -% being on the same expansion level than \cs{exp:w}, e.g., you may -% see code such as -%\begin{verbatim} -% \exp:w \@@_case:NnTF #1 {#2} { } { } -%\end{verbatim} -% where somewhere during the expansion of |\@@_case:NnTF| the -% \cs{exp_end:} gets generated. -% \begin{texnote} -% The current implementation uses \tn{romannumeral} hence ignores -% space tokens and explicit signs |+| and |-| in the expansion of the -% \meta{expandable tokens}, but this should not be relied upon. -% \end{texnote} -% \end{function} -% \footnotetext{Due to the implementation you might get the character -% in position 0 in the current font (typically \enquote{\texttt{`}}) -% in the output without any error message!} -% -% \begin{function}[added=2015-08-23, EXP, label = \exp_end_continue_f:w] -% { -% \exp:w , -% \exp_end_continue_f:w -% } -% \begin{syntax} -% \cs{exp:w} \meta{expandable-tokens} \cs{exp_end_continue_f:w} \meta{further-tokens} -% \end{syntax} -% Expands \meta{expandable-tokens} until reaching \cs{exp_end_continue_f:w} at -% which point expansion continues as an \texttt{f}-type expansion expanding -% \meta{further-tokens} until an unexpandable token is encountered (or -% the \texttt{f}-type expansion is explicitly terminated by -% \cs{exp_stop_f:}). As with all \texttt{f}-type expansions a space ending -% the expansion gets removed. -% -% The full expansion of \meta{expandable-tokens} has to be empty. -% If any token in \meta{expandable-tokens} or any token generated by -% expanding the tokens therein is not expandable the expansion will end -% prematurely and as a result \cs{exp_end_continue_f:w} will be misinterpreted -% later on.\footnotemark -% -% -% In typical use cases \meta{expandable-tokens} contains no tokens at all, -% e.g., you will see code such as -%\begin{verbatim} -% \exp_after:wN { \exp:w \exp_end_continue_f:w #2 } -%\end{verbatim} -% where the \cs{exp_after:wN} triggers an \texttt{f}-expansion of the tokens -% in |#2|. For technical reasons this has to happen using two tokens -% (if they would be hidden inside another command \cs{exp_after:wN} -% would only expand the command but not trigger any additional -% |f|-expansion). -% -% You might wonder why there are two different approaches available, -% after all the effect of -% \begin{quote} -% \cs{exp:w} \meta{expandable-tokens} \cs{exp_end:} -% \end{quote} -% can be alternatively achieved through an \texttt{f}-type expansion by using -% \cs{exp_stop_f:}, i.e. -% \begin{quote} -% \cs{exp:w} \cs{exp_end_continue_f:w} \meta{expandable-tokens} \cs{exp_stop_f:} -% \end{quote} -% The reason is simply that the first approach is slightly faster -% (one less token to parse and less expansion internally) -% so in places where such performance really matters and where we -% want to explicitly stop the expansion at a defined point the first -% form is preferable. -% \end{function} -% \footnotetext{In this particular case you may get a character into -% the output as well as an error message.} -% -% \begin{function}[added=2015-08-23, EXP, label = \exp_end_continue_f:nw] -% { -% \exp:w , -% \exp_end_continue_f:nw -% } -% \begin{syntax} -% \cs{exp:w} \meta{expandable-tokens} \cs{exp_end_continue_f:nw} \meta{further-tokens} -% \end{syntax} -% The difference to \cs{exp_end_continue_f:w} is that we first we pick -% up an argument which is then returned to the input stream. If -% \meta{further-tokens} starts with space tokens then these space -% tokens are removed while searching for the argument. If it starts -% with a brace group then the braces are removed. Thus such spaces or -% braces will not terminate the \texttt{f}-type expansion. -% \end{function} -% -% \section{Internal functions} -% -% \begin{function}{\::n, \::N, \::p, \::c, \::o, \::e, \::f, \::x, \::v, \::V, \:::} -% \begin{syntax} -% |\cs_new:Npn \exp_args:Ncof { \::c \::o \::f \::: }| -% \end{syntax} -% Internal forms for the base expansion types. These names do \emph{not} -% conform to the general \LaTeX3 approach as this makes them more readily -% visible in the log and so forth. They should not be used outside this module. -% \end{function} -% -% \begin{function} -% {\::o_unbraced, \::e_unbraced, \::f_unbraced, \::x_unbraced, \::v_unbraced, \::V_unbraced} -% \begin{syntax} -% |\cs_new:Npn \exp_last_unbraced:Nno { \::n \::o_unbraced \::: }| -% \end{syntax} -% Internal forms for the expansion types which leave the terminal argument -% unbraced. These names do \emph{not} -% conform to the general \LaTeX3 approach as this makes them more readily -% visible in the log and so forth. They should not be used outside this module. -% \end{function} -% -% \end{documentation} -% -% \begin{implementation} -% -% \section{\pkg{l3expan} implementation} -% -% \begin{macrocode} -%<*package> -% \end{macrocode} -% -% \begin{macrocode} -%<@@=exp> -% \end{macrocode} -% -% \begin{variable}{\l_@@_internal_tl} -% The |\exp_| module has its private variable to temporarily store the -% result of |x|-type argument expansion. This is done to avoid interference -% with other functions using temporary variables. -% \end{variable} -% -% \begin{macro}{\exp_after:wN} -% \begin{macro}{\exp_not:N} -% \begin{macro}{\exp_not:n} -% These are defined in \pkg{l3basics}, as they are needed -% \enquote{early}. This is just a reminder of that fact! -% \end{macro} -% \end{macro} -% \end{macro} -% -% \subsection{General expansion} -% -% In this section a general mechanism for defining functions that handle -% arguments is defined. These general expansion functions are -% expandable unless |x| is used. (Any version of |x| is going to have -% to use one of the \LaTeX3 names for \cs{cs_set:Npx} at some -% point, and so is never going to be expandable.) -% -% The definition of expansion functions with this technique happens -% in section~\ref{sec:l3expan:gendef}. -% In section~\ref{sec:l3expan:handtune} some common cases are coded by a more direct -% method for efficiency, typically using calls to \cs{exp_after:wN}. -% -% \begin{variable}{\l_@@_internal_tl} -% This scratch token list variable is defined in \pkg{l3basics}. -% \end{variable} -% -% This code uses internal functions with names that start with |\::| to -% perform the expansions. All macros are |long| since the tokens -% undergoing expansion may be arbitrary user input. -% -% An argument manipulator |\::|\meta{Z} always has signature |#1\:::#2#3| -% where |#1| holds the remaining argument manipulations to be performed, -% \cs{:::} serves as an end marker for the list of manipulations, |#2| -% is the carried over result of the previous expansion steps and |#3| is -% the argument about to be processed. -% One exception to this rule is \cs{::p}, which has to grab an argument -% delimited by a left brace. -% -% \begin{macro}[EXP]{\@@_arg_next:nnn} -% \begin{macro}[EXP]{\@@_arg_next:Nnn} -% |#1| is the result of an expansion step, |#2| is the remaining -% argument manipulations and |#3| is the current result of the -% expansion chain. This auxiliary function moves |#1| back after -% |#3| in the input stream and checks if any expansion is left to -% be done by calling |#2|. In by far the most cases we need -% to add a set of braces to the result of an argument manipulation -% so it is more effective to do it directly here. Actually, so far -% only the |c| of the final argument manipulation variants does not -% require a set of braces. -% \begin{macrocode} -\cs_new:Npn \@@_arg_next:nnn #1#2#3 { #2 \::: { #3 {#1} } } -\cs_new:Npn \@@_arg_next:Nnn #1#2#3 { #2 \::: { #3 #1 } } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}{\:::} -% The end marker is just another name for the identity function. -% \begin{macrocode} -\cs_new:Npn \::: #1 {#1} -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::n} -% This function is used to skip an argument that doesn't need to -% be expanded. -% \begin{macrocode} -\cs_new:Npn \::n #1 \::: #2#3 { #1 \::: { #2 {#3} } } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::N} -% This function is used to skip an argument that consists of a -% single token and doesn't need to be expanded. -% \begin{macrocode} -\cs_new:Npn \::N #1 \::: #2#3 { #1 \::: {#2#3} } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::p} -% This function is used to skip an argument that is delimited by a -% left brace and doesn't need to be expanded. It is not -% wrapped in braces in the result. -% \begin{macrocode} -\cs_new:Npn \::p #1 \::: #2#3# { #1 \::: {#2#3} } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::c} -% This function is used to skip an argument that is turned into -% a control sequence without expansion. -% \begin{macrocode} -\cs_new:Npn \::c #1 \::: #2#3 - { \exp_after:wN \@@_arg_next:Nnn \cs:w #3 \cs_end: {#1} {#2} } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::o} -% This function is used to expand an argument once. -% \begin{macrocode} -\cs_new:Npn \::o #1 \::: #2#3 - { \exp_after:wN \@@_arg_next:nnn \exp_after:wN {#3} {#1} {#2} } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::e} -% With the \tn{expanded} primitive available, just expand. -% \begin{macrocode} -\cs_new:Npn \::e #1 \::: #2#3 - { \tex_expanded:D { \exp_not:n { #1 \::: } { \exp_not:n {#2} {#3} } } } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::f} -% \begin{macro}{\exp_stop_f:} -% This function is used to expand a token list until the first -% unexpandable token is found. This is achieved through \cs{exp:w} -% \cs{exp_end_continue_f:w} that expands everything in its way -% following it. This scanning procedure is terminated once the -% expansion hits something non-expandable (if that is a space it is -% removed). We introduce \cs{exp_stop_f:} to mark such an -% end-of-expansion marker. For example, |f|-expanding -% |\cs_set_eq:Nc \aaa { b \l_tmpa_tl b }| where |\l_tmpa_tl| contains -% the characters |lur| gives |\tex_let:D \aaa = \blurb| which then -% turns out to start with the non-expandable token |\tex_let:D|. -% Since the expansion of \cs{exp:w} \cs{exp_end_continue_f:w} is -% empty, we wind up with a fully expanded list, only \TeX{} has not -% tried to execute any of the non-expandable tokens. This is what -% differentiates this function from the |e| and |x| argument type. -% \begin{macrocode} -\cs_new:Npn \::f #1 \::: #2#3 - { - \exp_after:wN \@@_arg_next:nnn - \exp_after:wN { \exp:w \exp_end_continue_f:w #3 } - {#1} {#2} - } -\use:nn { \cs_new_eq:NN \exp_stop_f: } { ~ } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}{\::x} -% This function is used to expand an argument fully. -% We build in the expansion of \cs{@@_arg_next:nnn}. -% \begin{macrocode} -\cs_new_protected:Npn \::x #1 \::: #2#3 - { - \cs_set_nopar:Npe \l_@@_internal_tl - { \exp_not:n { #1 \::: } { \exp_not:n {#2} {#3} } } - \l_@@_internal_tl - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\::v} -% \begin{macro}[EXP]{\::V} -% These functions return the value of a register, i.e., one of -% |tl|, |clist|, |int|, |skip|, |dim|, |muskip|, or built-in -% \TeX{} register. The |V| version -% expects a single token whereas |v| like |c| creates a csname from -% its argument given in braces and then evaluates it as if it was a -% |V|. The \cs{exp:w} sets off an expansion -% similar to an |f|-type expansion, which we terminate using -% \cs{exp_end:}. The argument is returned in braces. -% \begin{macrocode} -\cs_new:Npn \::V #1 \::: #2#3 - { - \exp_after:wN \@@_arg_next:nnn - \exp_after:wN { \exp:w \@@_eval_register:N #3 } - {#1} {#2} -} -\cs_new:Npn \::v #1 \::: #2#3 - { - \exp_after:wN \@@_arg_next:nnn - \exp_after:wN { \exp:w \@@_eval_register:c {#3} } - {#1} {#2} - } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}[EXP]{\@@_eval_register:N, \@@_eval_register:c} -% \begin{macro}[EXP]{\@@_eval_error_msg:w} -% This function evaluates a register. Now a register might exist as -% one of two things: A parameter-less macro or a built-in \TeX{} -% register such as |\count|. For the \TeX{} registers we have to -% utilize a \tn{the} whereas for the macros we merely have to -% expand them once. The trick is to find out when to use -% \tn{the} and when not to. What we want here is to find out -% whether the token expands to something else when hit with -% \cs{exp_after:wN}. The technique is to compare the meaning of the -% token in question when it has been prefixed with \cs{exp_not:N} -% and the token itself. If it is a macro, the prefixed -% \cs{exp_not:N} temporarily turns it into the primitive -% \cs{scan_stop:}. -% \begin{macrocode} -\cs_new:Npn \@@_eval_register:N #1 - { - \exp_after:wN \if_meaning:w \exp_not:N #1 #1 -% \end{macrocode} -% If the token was not a macro it may be a malformed variable from a -% |c| expansion in which case it is equal to the primitive -% \cs{scan_stop:}. In that case we throw an error. We could let \TeX{} -% do it for us but that would result in the rather obscure -% \begin{quote} -% |! You can't use `\relax' after \the.| -% \end{quote} -% which while quite true doesn't give many hints as to what actually -% went wrong. We provide something more sensible. -% \begin{macrocode} - \if_meaning:w \scan_stop: #1 - \@@_eval_error_msg:w - \fi: -% \end{macrocode} -% The next bit requires some explanation. The function must be -% initiated by \cs{exp:w} and we want to -% terminate this expansion chain by inserting the \cs{exp_end:} -% token. -% However, we have to expand the register |#1| before we do -% that. If it is a \TeX{} register, we need to execute the sequence -% |\exp_after:wN \exp_end: \tex_the:D #1| and if it is a macro we -% need to execute |\exp_after:wN \exp_end: #1|. We therefore issue -% the longer of the two sequences and if the register is a macro, we -% remove the \cs{tex_the:D}. -% \begin{macrocode} - \else: - \exp_after:wN \use_i_ii:nnn - \fi: - \exp_after:wN \exp_end: \tex_the:D #1 - } -\cs_new:Npn \@@_eval_register:c #1 - { \exp_after:wN \@@_eval_register:N \cs:w #1 \cs_end: } -% \end{macrocode} -% Clean up nicely, then call the undefined control sequence. The -% result is an error message looking like this: -% \begin{verbatim} -% ! Undefined control sequence. -% <argument> \LaTeX3 error: -% Erroneous variable used! -% l.55 \tl_set:Nv \l_tmpa_tl {undefined_tl} -% \end{verbatim} -% \begin{macrocode} -\cs_new:Npn \@@_eval_error_msg:w #1 \tex_the:D #2 - { - \fi: - \fi: - \msg_expandable_error:nnn { kernel } { bad-variable } {#2} - \exp_end: - } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \subsection{Hand-tuned definitions} -% \label{sec:l3expan:handtune} -% -% One of the most important features of these functions is that they -% are fully expandable. -% -% \begin{macro}[EXP]{\exp_args:Nc, \exp_args:cc} -% In \pkg{l3basics}. -% \end{macro} -% -% \begin{macro}[EXP]{\exp_args:NNc, \exp_args:Ncc, \exp_args:Nccc} -% Here are the functions that turn their argument into csnames but are -% expandable. -% \begin{macrocode} -\cs_new:Npn \exp_args:NNc #1#2#3 - { \exp_after:wN #1 \exp_after:wN #2 \cs:w # 3\cs_end: } -\cs_new:Npn \exp_args:Ncc #1#2#3 - { \exp_after:wN #1 \cs:w #2 \exp_after:wN \cs_end: \cs:w #3 \cs_end: } -\cs_new:Npn \exp_args:Nccc #1#2#3#4 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \cs:w #3 \exp_after:wN \cs_end: - \cs:w #4 \cs_end: - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\exp_args:No} -% \begin{macro}[EXP]{\exp_args:NNo} -% \begin{macro}[EXP]{\exp_args:NNNo} -% Those lovely runs of expansion! -% \begin{macrocode} -\cs_new:Npn \exp_args:No #1#2 { \exp_after:wN #1 \exp_after:wN {#2} } -\cs_new:Npn \exp_args:NNo #1#2#3 - { \exp_after:wN #1 \exp_after:wN #2 \exp_after:wN {#3} } -\cs_new:Npn \exp_args:NNNo #1#2#3#4 - { \exp_after:wN #1 \exp_after:wN#2 \exp_after:wN #3 \exp_after:wN {#4} } -% \end{macrocode} -% \end{macro} -% \end{macro} -% \end{macro} -% -% \begin{macro}[EXP]{\exp_args:Ne} -% When the \tn{expanded} primitive is available, use it. -% \begin{macrocode} -\cs_new:Npn \exp_args:Ne #1#2 - { \exp_after:wN #1 \tex_expanded:D { {#2} } } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\exp_args:Nf, \exp_args:NV, \exp_args:Nv} -% \begin{macrocode} -\cs_new:Npn \exp_args:Nf #1#2 - { \exp_after:wN #1 \exp_after:wN { \exp:w \exp_end_continue_f:w #2 } } -\cs_new:Npn \exp_args:Nv #1#2 - { - \exp_after:wN #1 \exp_after:wN - { \exp:w \@@_eval_register:c {#2} } - } -\cs_new:Npn \exp_args:NV #1#2 - { - \exp_after:wN #1 \exp_after:wN - { \exp:w \@@_eval_register:N #2 } - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP] -% { -% \exp_args:NNV, \exp_args:NNv, \exp_args:NNe, \exp_args:NNf, -% \exp_args:Nco, \exp_args:NcV, \exp_args:Ncv, \exp_args:Ncf, -% \exp_args:NVV, -% } -% Some more hand-tuned function with three arguments. -% If we forced that an |o| argument always has braces, -% we could implement \cs{exp_args:Nco} with less tokens -% and only two arguments. -% \begin{macrocode} -\cs_new:Npn \exp_args:NNV #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN { \exp:w \@@_eval_register:N #3 } - } -\cs_new:Npn \exp_args:NNv #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN { \exp:w \@@_eval_register:c {#3} } - } -\cs_new:Npn \exp_args:NNe #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \tex_expanded:D { {#3} } - } -\cs_new:Npn \exp_args:NNf #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN { \exp:w \exp_end_continue_f:w #3 } - } -\cs_new:Npn \exp_args:Nco #1#2#3 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN {#3} - } -\cs_new:Npn \exp_args:NcV #1#2#3 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN { \exp:w \@@_eval_register:N #3 } - } -\cs_new:Npn \exp_args:Ncv #1#2#3 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN { \exp:w \@@_eval_register:c {#3} } - } -\cs_new:Npn \exp_args:Ncf #1#2#3 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN { \exp:w \exp_end_continue_f:w #3 } - } -\cs_new:Npn \exp_args:NVV #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN { \exp:w \exp_after:wN - \@@_eval_register:N \exp_after:wN #2 \exp_after:wN } - \exp_after:wN { \exp:w \@@_eval_register:N #3 } - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP] -% { -% \exp_args:NNNV, \exp_args:NNNv, \exp_args:NNNe, -% \exp_args:NcNc, \exp_args:NcNo, -% \exp_args:Ncco, -% } -% A few more that we can hand-tune. -% \begin{macrocode} -\cs_new:Npn \exp_args:NNNV #1#2#3#4 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \exp_after:wN { \exp:w \@@_eval_register:N #4 } - } -\cs_new:Npn \exp_args:NNNv #1#2#3#4 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \exp_after:wN { \exp:w \@@_eval_register:c {#4} } - } -\cs_new:Npn \exp_args:NNNe #1#2#3#4 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \tex_expanded:D { {#4} } - } -\cs_new:Npn \exp_args:NcNc #1#2#3#4 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN #3 - \cs:w #4 \cs_end: - } -\cs_new:Npn \exp_args:NcNo #1#2#3#4 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp_after:wN #3 - \exp_after:wN {#4} - } -\cs_new:Npn \exp_args:Ncco #1#2#3#4 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \cs:w #3 \exp_after:wN \cs_end: - \exp_after:wN {#4} - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\exp_args:Nx} -% \begin{macrocode} -\cs_new_protected:Npn \exp_args:Nx #1#2 - { \use:x { \exp_not:N #1 {#2} } } -% \end{macrocode} -% \end{macro} -% -% \subsection{Last-unbraced versions} -% -% \begin{macro}[EXP]{\@@_arg_last_unbraced:nn} -% \begin{macro}[EXP]{\::o_unbraced} -% \begin{macro}[EXP]{\::V_unbraced} -% \begin{macro}[EXP]{\::v_unbraced} -% \begin{macro}[EXP]{\::e_unbraced} -% \begin{macro}[EXP]{\::f_unbraced} -% \begin{macro}[EXP]{\::x_unbraced} -% There are a few places where the last argument needs to be available -% unbraced. First some helper macros. -% \begin{macrocode} -\cs_new:Npn \@@_arg_last_unbraced:nn #1#2 { #2#1 } -\cs_new:Npn \::o_unbraced \::: #1#2 - { \exp_after:wN \@@_arg_last_unbraced:nn \exp_after:wN {#2} {#1} } -\cs_new:Npn \::V_unbraced \::: #1#2 - { - \exp_after:wN \@@_arg_last_unbraced:nn - \exp_after:wN { \exp:w \@@_eval_register:N #2 } {#1} - } -\cs_new:Npn \::v_unbraced \::: #1#2 - { - \exp_after:wN \@@_arg_last_unbraced:nn - \exp_after:wN { \exp:w \@@_eval_register:c {#2} } {#1} - } -\cs_new:Npn \::e_unbraced \::: #1#2 - { \tex_expanded:D { \exp_not:n {#1} #2 } } -\cs_new:Npn \::f_unbraced \::: #1#2 - { - \exp_after:wN \@@_arg_last_unbraced:nn - \exp_after:wN { \exp:w \exp_end_continue_f:w #2 } {#1} - } -\cs_new_protected:Npn \::x_unbraced \::: #1#2 - { - \cs_set_nopar:Npe \l_@@_internal_tl { \exp_not:n {#1} #2 } - \l_@@_internal_tl - } -% \end{macrocode} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% -% \begin{macro}[EXP] -% { -% \exp_last_unbraced:No, -% \exp_last_unbraced:NV, -% \exp_last_unbraced:Nv, -% \exp_last_unbraced:Ne, -% \exp_last_unbraced:Nf, -% \exp_last_unbraced:NNo, -% \exp_last_unbraced:NNV, -% \exp_last_unbraced:NNf, -% \exp_last_unbraced:Nco, -% \exp_last_unbraced:NcV, -% \exp_last_unbraced:NNNo, -% \exp_last_unbraced:NNNV, -% \exp_last_unbraced:NNNf, -% \exp_last_unbraced:Nno, -% \exp_last_unbraced:Nnf, -% \exp_last_unbraced:Noo, -% \exp_last_unbraced:Nfo, -% \exp_last_unbraced:NnNo, -% \exp_last_unbraced:NNNNo, -% \exp_last_unbraced:NNNNf, -% } -% \begin{macro}{\exp_last_unbraced:Nx} -% Now the business end: most of these are hand-tuned for speed, but the -% general system is in place. -% \begin{macrocode} -\cs_new:Npn \exp_last_unbraced:No #1#2 { \exp_after:wN #1 #2 } -\cs_new:Npn \exp_last_unbraced:NV #1#2 - { \exp_after:wN #1 \exp:w \@@_eval_register:N #2 } -\cs_new:Npn \exp_last_unbraced:Nv #1#2 - { \exp_after:wN #1 \exp:w \@@_eval_register:c {#2} } -\cs_new:Npn \exp_last_unbraced:Ne #1#2 - { \exp_after:wN #1 \tex_expanded:D {#2} } -\cs_new:Npn \exp_last_unbraced:Nf #1#2 - { \exp_after:wN #1 \exp:w \exp_end_continue_f:w #2 } -\cs_new:Npn \exp_last_unbraced:NNo #1#2#3 - { \exp_after:wN #1 \exp_after:wN #2 #3 } -\cs_new:Npn \exp_last_unbraced:NNV #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp:w \@@_eval_register:N #3 - } -\cs_new:Npn \exp_last_unbraced:NNf #1#2#3 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp:w \exp_end_continue_f:w #3 - } -\cs_new:Npn \exp_last_unbraced:Nco #1#2#3 - { \exp_after:wN #1 \cs:w #2 \exp_after:wN \cs_end: #3 } -\cs_new:Npn \exp_last_unbraced:NcV #1#2#3 - { - \exp_after:wN #1 - \cs:w #2 \exp_after:wN \cs_end: - \exp:w \@@_eval_register:N #3 - } -\cs_new:Npn \exp_last_unbraced:NNNo #1#2#3#4 - { \exp_after:wN #1 \exp_after:wN #2 \exp_after:wN #3 #4 } -\cs_new:Npn \exp_last_unbraced:NNNV #1#2#3#4 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \exp:w \@@_eval_register:N #4 - } -\cs_new:Npn \exp_last_unbraced:NNNf #1#2#3#4 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \exp:w \exp_end_continue_f:w #4 - } -\cs_new:Npn \exp_last_unbraced:Nno { \::n \::o_unbraced \::: } -\cs_new:Npn \exp_last_unbraced:Nnf { \::n \::f_unbraced \::: } -\cs_new:Npn \exp_last_unbraced:Noo { \::o \::o_unbraced \::: } -\cs_new:Npn \exp_last_unbraced:Nfo { \::f \::o_unbraced \::: } -\cs_new:Npn \exp_last_unbraced:NnNo { \::n \::N \::o_unbraced \::: } -\cs_new:Npn \exp_last_unbraced:NNNNo #1#2#3#4#5 - { \exp_after:wN #1 \exp_after:wN #2 \exp_after:wN #3 \exp_after:wN #4 #5 } -\cs_new:Npn \exp_last_unbraced:NNNNf #1#2#3#4#5 - { - \exp_after:wN #1 - \exp_after:wN #2 - \exp_after:wN #3 - \exp_after:wN #4 - \exp:w \exp_end_continue_f:w #5 - } -\cs_new_protected:Npn \exp_last_unbraced:Nx { \::x_unbraced \::: } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}[EXP]{\exp_last_two_unbraced:Noo} -% \begin{macro}[EXP]{\@@_last_two_unbraced:noN} -% If |#2| is a single token then this can be implemented as -% \begin{verbatim} -% \cs_new:Npn \exp_last_two_unbraced:Noo #1 #2 #3 -% { \exp_after:wN \exp_after:wN \exp_after:wN #1 \exp_after:wN #2 #3 } -% \end{verbatim} -% However, for robustness this is not suitable. Instead, a bit of a -% shuffle is used to ensure that |#2| can be multiple tokens. -% \begin{macrocode} -\cs_new:Npn \exp_last_two_unbraced:Noo #1#2#3 - { \exp_after:wN \@@_last_two_unbraced:noN \exp_after:wN {#3} {#2} #1 } -\cs_new:Npn \@@_last_two_unbraced:noN #1#2#3 - { \exp_after:wN #3 #2 #1 } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \subsection{Preventing expansion} -% -% \begin{macro}{\__kernel_exp_not:w} -% At the kernel level, we need the primitive behaviour to allow expansion -% \emph{before} the brace group. -% \begin{macrocode} -\cs_new_eq:NN \__kernel_exp_not:w \tex_unexpanded:D -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[EXP]{\exp_not:c} -% \begin{macro}[EXP]{\exp_not:o} -% \begin{macro}[EXP]{\exp_not:e} -% \begin{macro}[EXP]{\exp_not:f} -% \begin{macro}[EXP]{\exp_not:V} -% \begin{macro}[EXP]{\exp_not:v} -% All these except \cs{exp_not:c} call the kernel-internal -% \cs{__kernel_exp_not:w} namely \cs{tex_unexpanded:D}. -% \begin{macrocode} -\cs_new:Npn \exp_not:c #1 { \exp_after:wN \exp_not:N \cs:w #1 \cs_end: } -\cs_new:Npn \exp_not:o #1 { \__kernel_exp_not:w \exp_after:wN {#1} } -\cs_new:Npn \exp_not:e #1 - { \__kernel_exp_not:w \tex_expanded:D { {#1} } } -\cs_new:Npn \exp_not:f #1 - { \__kernel_exp_not:w \exp_after:wN { \exp:w \exp_end_continue_f:w #1 } } -\cs_new:Npn \exp_not:V #1 - { - \__kernel_exp_not:w \exp_after:wN - { \exp:w \@@_eval_register:N #1 } - } -\cs_new:Npn \exp_not:v #1 - { - \__kernel_exp_not:w \exp_after:wN - { \exp:w \@@_eval_register:c {#1} } - } -% \end{macrocode} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% -% \subsection{Controlled expansion} -% -% \begin{macro}{\exp:w} -% \begin{macro}{\exp_end:} -% \begin{macro}{\exp_end_continue_f:w} -% \begin{macro}{\exp_end_continue_f:nw} -% To trigger a sequence of \enquote{arbitrarily} many expansions we -% need a method to invoke \TeX's expansion mechanism in such a way -% that (a) we are able to stop it in a controlled manner and (b) the -% result of what triggered the expansion in the first place is null, -% i.e.\@, that we do not get any unwanted side effects. There aren't -% that many possibilities in \TeX{}; in fact the one explained below -% might well be the only one (as normally the result of expansion is -% not null). -% -% The trick here is to make use of the fact that -% \cs{tex_romannumeral:D} expands the tokens following it when looking -% for a number and that its expansion is null if that number turns out -% to be zero or negative. So we use that to start the expansion -% sequence: \cs{exp:w} is set equal to \cs{tex_romannumeral:D} in -% \pkg{l3basics}. To stop the expansion sequence in a controlled way -% all we need to provide is a constant integer zero as part of -% expanded tokens. As this is an integer constant it immediately stops -% \cs{tex_romannumeral:D}'s search for a number. Again, the -% definition of \cs{exp_end:} as the integer constant zero is in -% \pkg{l3basics}. (Note that according to our specification all -% tokens we expand initiated by \cs{exp:w} are supposed to be -% expandable (as well as their replacement text in the expansion) so -% we will not encounter a \enquote{number} that actually result in a -% roman numeral being generated. Or if we do then the programmer made -% a mistake.) -% -% If on the other hand we want to stop the initial expansion sequence -% but continue with an \texttt{f}-type expansion we provide the -% alphabetic constant |`^^@| that also represents |0| but this time -% \TeX's syntax for a \meta{number} continues searching for an -% optional space (and it continues expansion doing that) --- see -% \TeX{}book page~269 for details. -% \begin{macrocode} -\group_begin: - \tex_catcode:D `\^^@ = 13 - \cs_new_protected:Npn \exp_end_continue_f:w { `^^@ } -% \end{macrocode} -% If the above definition ever appears outside its proper context -% the active character |^^@| will be executed so we turn this into an -% error. The test for existence covers the (unlikely) case that some -% other code has already defined |^^@|: this is true for example for -% \texttt{xmltex.tex}. -% \begin{macrocode} - \if_cs_exist:N ^^@ - \else: - \cs_new:Npn ^^@ - { \msg_expandable_error:nn { kernel } { bad-exp-end-f } } - \fi: -% \end{macrocode} -% The same but grabbing an argument to remove spaces and braces. -% \begin{macrocode} - \cs_new:Npn \exp_end_continue_f:nw #1 { `^^@ #1 } -\group_end: -% \end{macrocode} -% \end{macro} -% \end{macro} -% \end{macro} -% \end{macro} -% -% \subsection{Defining function variants} -% -% \begin{macrocode} -%<@@=cs> -% \end{macrocode} -% -% \begin{variable}{\s_@@_mark,\s_@@_stop} -% Internal scan marks. No \pkg{l3quark} yet, so do things by hand. -% \begin{macrocode} -\cs_new_eq:NN \s_@@_mark \scan_stop: -\cs_new_eq:NN \s_@@_stop \scan_stop: -% \end{macrocode} -% \end{variable} -% -% \begin{variable}{\q_@@_recursion_stop} -% Internal recursion quarks. No \pkg{l3quark} yet, so do things by hand. -% \begin{macrocode} -\cs_new:Npn \q_@@_recursion_stop { \q_@@_recursion_stop } -% \end{macrocode} -% \end{variable} -% -% \begin{macro}[EXP]{ -% \@@_use_none_delimit_by_s_stop:w, -% \@@_use_i_delimit_by_s_stop:nw, -% \@@_use_none_delimit_by_q_recursion_stop:w -% } -% Internal scan marks. -% \begin{macrocode} -\cs_new:Npn \@@_use_none_delimit_by_s_stop:w #1 \s_@@_stop { } -\cs_new:Npn \@@_use_i_delimit_by_s_stop:nw #1 #2 \s_@@_stop {#1} -\cs_new:Npn \@@_use_none_delimit_by_q_recursion_stop:w - #1 \q_@@_recursion_stop { } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\cs_generate_variant:Nn, \cs_generate_variant:cn} -% \begin{arguments} -% \item Base form of a function; \emph{e.g.},~\cs{tl_set:Nn} -% \item One or more variant argument specifiers; e.g., |{Nx,c,cx}| -% \end{arguments} -% After making sure that the base form exists, test whether it is -% protected or not and define \cs{@@_tmp:w} as either -% \cs{cs_new:Npe} or \cs{cs_new_protected:Npe}, which is -% then used to define all the variants (except those involving -% \texttt{x}-expansion, always protected). Split up the original base -% function only once, to grab its name and signature. Then we wish to -% iterate through the comma list of variant argument specifiers, which -% we first convert to a string: the reason is explained later. -% \begin{macrocode} -\cs_new_protected:Npn \cs_generate_variant:Nn #1#2 - { - \@@_generate_variant:N #1 - \use:e - { - \@@_generate_variant:nnNN - \cs_split_function:N #1 - \exp_not:N #1 - \tl_to_str:n {#2} , - \exp_not:N \scan_stop: , - \exp_not:N \q_@@_recursion_stop - } - } -\cs_new_protected:Npn \cs_generate_variant:cn - { \exp_args:Nc \cs_generate_variant:Nn } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\@@_generate_variant:N} -% \begin{macro}{\@@_generate_variant:ww, \@@_generate_variant:wwNw} -% The goal here is to pick up protected parent functions. There are -% four cases: the parent function can be a primitive or a macro, and -% can be expandable or not. For non-expandable primitives, all -% variants should be protected; skipping the \cs{else:} branch is safe -% because non-expandable primitives cannot be \TeX{} conditionals. -% -% The other case where variants should be protected is when the parent -% function is a protected macro: then |protected| appears in the -% meaning before the first occurrence of |macro|. The |ww| auxiliary -% removes everything in the meaning string after the first |ma|. We -% use |ma| rather than the full |macro| because the meaning of the -% \tn{firstmark} primitive (and four others) can contain an arbitrary -% string after a leading |firstmark:|. Then, look for |pr| in the -% part we extracted: no need to look for anything longer: the only -% strings we can have are an empty string, \verb*|\long |, -% \verb*|\protected |, \verb*|\protected\long |, |\first|, |\top|, -% |\bot|, |\splittop|, or |\splitbot|, with |\| replaced by the -% appropriate escape character. If |pr| appears in the part before -% |ma|, the first \cs{s_@@_mark} is taken as an argument of the |wwNw| -% auxiliary, and |#3| is \cs{cs_new_protected:Npe}, otherwise it -% is \cs{cs_new:Npe}. -% \begin{macrocode} -\cs_new_protected:Npe \@@_generate_variant:N #1 - { - \exp_not:N \exp_after:wN \exp_not:N \if_meaning:w - \exp_not:N \exp_not:N #1 #1 - \cs_set_eq:NN \exp_not:N \@@_tmp:w \cs_new_protected:Npe - \exp_not:N \else: - \exp_not:N \exp_after:wN \exp_not:N \@@_generate_variant:ww - \exp_not:N \token_to_meaning:N #1 \tl_to_str:n { ma } - \s_@@_mark - \s_@@_mark \cs_new_protected:Npe - \tl_to_str:n { pr } - \s_@@_mark \cs_new:Npe - \s_@@_stop - \exp_not:N \fi: - } -\exp_last_unbraced:NNNNo - \cs_new_protected:Npn \@@_generate_variant:ww - #1 { \tl_to_str:n { ma } } #2 \s_@@_mark - { \@@_generate_variant:wwNw #1 } -\exp_last_unbraced:NNNNo - \cs_new_protected:Npn \@@_generate_variant:wwNw - #1 { \tl_to_str:n { pr } } #2 \s_@@_mark #3 #4 \s_@@_stop - { \cs_set_eq:NN \@@_tmp:w #3 } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}{\@@_generate_variant:nnNN} -% \begin{arguments} -% \item Base name. -% \item Base signature. -% \item Boolean. -% \item Base function. -% \end{arguments} -% If the boolean is \cs{c_false_bool}, the base function has no colon -% and we abort with an error; otherwise, set off a loop through the -% desired variant forms. The original function is retained as |#4| for -% efficiency. -% \begin{macrocode} -\cs_new_protected:Npn \@@_generate_variant:nnNN #1#2#3#4 - { - \if_meaning:w \c_false_bool #3 - \msg_error:nne { kernel } { missing-colon } - { \token_to_str:c {#1} } - \exp_after:wN \@@_use_none_delimit_by_q_recursion_stop:w - \fi: - \@@_generate_variant:Nnnw #4 {#1}{#2} - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\@@_generate_variant:Nnnw} -% \begin{arguments} -% \item Base function. -% \item Base name. -% \item Base signature. -% \item Beginning of variant signature. -% \end{arguments} -% First check whether to terminate the loop over variant forms. Then, -% for each variant form, construct a new function name using the -% original base name, the variant signature consisting of $l$ letters -% and the last $k-l$ letters of the base signature (of length $k$). -% For example, for a base function \cs{prop_put:Nnn} which needs a -% |cV| variant form, we want the new signature to be |cVn|. -% -% There are further subtleties: -% \begin{itemize} -% \item In \cs{cs_generate_variant:Nn} |\foo:nnTF| |{xxTF}|, we must define -% |\foo:xxTF| using |\exp_args:Nxx|, -% rather than a hypothetical |\exp_args:NxxTF|. Thus, we wish to -% trim a common trailing part from the base signature and the -% variant signature. -% \item In \cs{cs_generate_variant:Nn} |\foo:on| |{ox}|, the -% function |\foo:ox| must be defined using |\exp_args:Nnx|, not -% |\exp_args:Nox|, to avoid double |o| expansion. -% \item Lastly, \cs{cs_generate_variant:Nn} |\foo:on| |{xn}| must -% trigger an error, because we do not have a means to replace -% |o|-expansion by |x|-expansion. -% More generally, we can only convert |N| to |c|, or convert |n| -% to |V|, |v|, |o|, |e|, |f|, or |x|. -% \end{itemize} -% All this boils down to a few rules. Only |n| and |N|-type -% arguments can be replaced by \cs{cs_generate_variant:Nn}. Other -% argument types are allowed to be passed unchanged from the base -% form to the variant: in the process they are changed to |n| -% except for |N| and |p|-type arguments. A common trailing -% part is ignored. -% -% We compare the base and variant signatures one character at a time -% within |e|-expansion. The result is given to -% \cs{@@_generate_variant:wwNN} (defined later) in the form -% \meta{processed variant signature} \cs{s_@@_mark} \meta{errors} -% \cs{s_@@_stop} \meta{base function} \meta{new function}. If all went -% well, \meta{errors} is empty; otherwise, it is a kernel error -% message and some clean-up code. -% -% Note the space after |#3| and after the following brace group. -% Those are ignored by \TeX{} when fetching the last argument for -% \cs{@@_generate_variant_loop:nNwN}, but can be used as a delimiter -% for \cs{@@_generate_variant_loop_end:nwwwNNnn}. -% \begin{macrocode} -\cs_new_protected:Npn \@@_generate_variant:Nnnw #1#2#3#4 , - { - \if_meaning:w \scan_stop: #4 - \exp_after:wN \@@_use_none_delimit_by_q_recursion_stop:w - \fi: - \use:e - { - \exp_not:N \@@_generate_variant:wwNN - \@@_generate_variant_loop:nNwN { } - #4 - \@@_generate_variant_loop_end:nwwwNNnn - \s_@@_mark - #3 ~ - { ~ { } \fi: \@@_generate_variant_loop_long:wNNnn } ~ - { } - \s_@@_stop - \exp_not:N #1 {#2} {#4} - } - \@@_generate_variant:Nnnw #1 {#2} {#3} - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[rEXP] -% { -% \@@_generate_variant_loop:nNwN, -% \@@_generate_variant_loop_base:N, -% \@@_generate_variant_loop_same:w, -% \@@_generate_variant_loop_end:nwwwNNnn, -% \@@_generate_variant_loop_long:wNNnn, -% \@@_generate_variant_loop_invalid:NNwNNnn, -% \@@_generate_variant_loop_special:NNwNNnn -% } -% \begin{arguments} -% \item Last few consecutive letters common between the base and -% variant (more precisely, \cs{@@_generate_variant_same:N} -% \meta{letter} for each letter). -% \item Next variant letter. -% \item Remainder of variant form. -% \item Next base letter. -% \end{arguments} -% The first argument is populated by -% \cs{@@_generate_variant_loop_same:w} when a variant letter and a -% base letter match. It is flushed into the input stream whenever the -% two letters are different: if the loop ends before, the argument is -% dropped, which means that trailing common letters are ignored. -% -% The case where the two letters are different is only allowed if the -% base is |N| and the variant is |c|, or when the base is |n| and the -% variant is |V|, |v|, |o|, |e|, |f|, or |x|. Otherwise, call -% \cs{@@_generate_variant_loop_invalid:NNwNNnn} to remove the end of -% the loop, get arguments at the end of the loop, and place an -% appropriate error message as a second argument of -% \cs{@@_generate_variant:wwNN}. If the letters are distinct and the -% base letter is indeed |n| or |N|, leave in the input stream whatever -% argument |#1| was collected, and the next variant letter |#2|, then -% loop by calling \cs{@@_generate_variant_loop:nNwN}. -% -% The loop can stop in three ways. -% \begin{itemize} -% \item If the end of the variant form is encountered first, |#2| is -% \cs{@@_generate_variant_loop_end:nwwwNNnn} (expanded by the -% conditional \cs{if:w}), which inserts some tokens to end the -% conditional; grabs the \meta{base name} as |#7|, the -% \meta{variant signature} |#8|, the \meta{next base letter} |#1| -% and the part |#3| of the base signature that wasn't read yet; -% and combines those into the \meta{new function} to be defined. -% \item If the end of the base form is encountered first, |#4| is -% |~{}\fi:| which ends the conditional (with an empty expansion), -% followed by \cs{@@_generate_variant_loop_long:wNNnn}, which -% places an error as the second argument of -% \cs{@@_generate_variant:wwNN}. -% \item The loop can be interrupted early if the requested expansion -% is unavailable, namely when the variant and base letters differ -% and the base is not the right one (|n| or |N| to support the -% variant). In that case too an error is placed as the second -% argument of \cs{@@_generate_variant:wwNN}. -% \end{itemize} -% Note that if the variant form has the same length as the base form, -% |#2| is as described in the first point, and |#4| as described in -% the second point above. The \cs{@@_generate_variant_loop_end:nwwwNNnn} -% breaking function takes the empty brace group in |#4| as its first -% argument: this empty brace group produces the correct signature for -% the full variant. -% \begin{macrocode} -\cs_new:Npn \@@_generate_variant_loop:nNwN #1#2#3 \s_@@_mark #4 - { - \if:w #2 #4 - \exp_after:wN \@@_generate_variant_loop_same:w - \else: - \if:w #4 \@@_generate_variant_loop_base:N #2 \else: - \if:w 0 - \if:w N #4 \else: \if:w n #4 \else: 1 \fi: \fi: - \if:w \scan_stop: \@@_generate_variant_loop_base:N #2 1 \fi: - 0 - \@@_generate_variant_loop_special:NNwNNnn #4#2 - \else: - \@@_generate_variant_loop_invalid:NNwNNnn #4#2 - \fi: - \fi: - \fi: - #1 - \prg_do_nothing: - #2 - \@@_generate_variant_loop:nNwN { } #3 \s_@@_mark - } -\cs_new:Npn \@@_generate_variant_loop_base:N #1 - { - \if:w c #1 N \else: - \if:w o #1 n \else: - \if:w V #1 n \else: - \if:w v #1 n \else: - \if:w f #1 n \else: - \if:w e #1 n \else: - \if:w x #1 n \else: - \if:w n #1 n \else: - \if:w N #1 N \else: - \scan_stop: - \fi: - \fi: - \fi: - \fi: - \fi: - \fi: - \fi: - \fi: - \fi: - } -\cs_new:Npn \@@_generate_variant_loop_same:w - #1 \prg_do_nothing: #2#3#4 - { #3 { #1 \@@_generate_variant_same:N #2 } } -\cs_new:Npn \@@_generate_variant_loop_end:nwwwNNnn - #1#2 \s_@@_mark #3 ~ #4 \s_@@_stop #5#6#7#8 - { - \scan_stop: \scan_stop: \fi: - \s_@@_mark \s_@@_stop - \exp_not:N #6 - \exp_not:c { #7 : #8 #1 #3 } - } -\cs_new:Npn \@@_generate_variant_loop_long:wNNnn #1 \s_@@_stop #2#3#4#5 - { - \exp_not:n - { - \s_@@_mark - \msg_error:nnee { kernel } { variant-too-long } - {#5} { \token_to_str:N #3 } - \use_none:nnn - \s_@@_stop - #3 - #3 - } - } -\cs_new:Npn \@@_generate_variant_loop_invalid:NNwNNnn - #1#2 \fi: \fi: \fi: #3 \s_@@_stop #4#5#6#7 - { - \fi: \fi: \fi: - \exp_not:n - { - \s_@@_mark - \msg_error:nneeee { kernel } { invalid-variant } - {#7} { \token_to_str:N #5 } {#1} {#2} - \use_none:nnn - \s_@@_stop - #5 - #5 - } - } -\cs_new:Npn \@@_generate_variant_loop_special:NNwNNnn - #1#2#3 \s_@@_stop #4#5#6#7 - { - #3 \s_@@_stop #4 #5 {#6} {#7} - \exp_not:n - { - \msg_error:nneeee - { kernel } { deprecated-variant } - {#7} { \token_to_str:N #5 } {#1} {#2} - } - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}[rEXP]{\@@_generate_variant_same:N} -% When the base and variant letters are identical, don't do any -% expansion. For most argument types, we can use the |n|-type -% no-expansion, but the |N| and |p| types require a slightly different -% behaviour with respect to braces. For |V|-type this function could -% output |N| to avoid adding useless braces but that is not a problem. -% \begin{macrocode} -\cs_new:Npn \@@_generate_variant_same:N #1 - { - \if:w N #1 #1 \else: - \if:w p #1 #1 \else: - \token_to_str:N n - \if:w n #1 \else: - \@@_generate_variant_loop_special:NNwNNnn #1#1 - \fi: - \fi: - \fi: - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\@@_generate_variant:wwNN} -% If the variant form has already been defined, log its existence -% (provided \texttt{log-functions} is active). -% Otherwise, make sure that the |\exp_args:N #3| form is defined, and -% if it contains |x|, change \cs{@@_tmp:w} locally to -% \cs{cs_new_protected:Npe}. Then define the variant by -% combining the |\exp_args:N #3| variant and the base function. -% \begin{macrocode} -\cs_new_protected:Npn \@@_generate_variant:wwNN - #1 \s_@@_mark #2 \s_@@_stop #3#4 - { - #2 - \cs_if_free:NT #4 - { - \group_begin: - \@@_generate_internal_variant:n {#1} - \@@_tmp:w #4 { \exp_not:c { exp_args:N #1 } \exp_not:N #3 } - \group_end: - } - } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\@@_generate_internal_variant:n} -% \begin{macro}[rEXP]{\@@_generate_internal_variant_loop:n} -% First test for the presence of |x| (this is where working with -% strings makes our lives easier), as the result should be protected, -% and the next variant to be defined using that internal variant -% should be protected (done by setting \cs{@@_tmp:w}). Then call -% \cs{@@_generate_internal_variant:NNn} with arguments -% \cs{cs_new_protected:cpn} \cs{use:x} (for protected) or -% \cs{cs_new:cpn} \cs{tex_expanded:D} (expandable) and the signature. If |p| -% appears in the signature, or if the function to be defined is -% expandable and the primitive \tn{expanded} is not available, or if there -% are more than $8$ arguments, call -% some fall-back code that just puts the appropriate |\::| commands. -% Otherwise, call \cs{@@_generate_internal_one_go:NNn} to construct -% the \cs[no-index]{exp_args:N\dots} function as a macro taking up to -% $9$~arguments and expanding them using \cs{use:x} or \cs{tex_expanded:D}. -% \begin{macrocode} -\cs_new_protected:Npe \@@_generate_internal_variant:n #1 - { - \exp_not:N \@@_generate_internal_variant:wwnNwn - #1 \s_@@_mark - { \cs_set_eq:NN \exp_not:N \@@_tmp:w \cs_new_protected:Npe } - \cs_new_protected:cpn - \use:x - \token_to_str:N x \s_@@_mark - { } - \cs_new:cpn - \exp_not:N \tex_expanded:D - \s_@@_stop - {#1} - } -\exp_last_unbraced:NNNNo - \cs_new_protected:Npn \@@_generate_internal_variant:wwnNwn #1 - { \token_to_str:N x } #2 \s_@@_mark #3#4#5#6 \s_@@_stop #7 - { - #3 - \cs_if_free:cT { exp_args:N #7 } - { \@@_generate_internal_variant:NNn #4 #5 {#7} } - } -\cs_set_protected:Npn \@@_tmp:w #1 - { - \cs_new_protected:Npn \@@_generate_internal_variant:NNn ##1##2##3 - { - \if_catcode:w X \use_none:nnnnnnnn ##3 - \prg_do_nothing: \prg_do_nothing: \prg_do_nothing: - \prg_do_nothing: \prg_do_nothing: \prg_do_nothing: - \prg_do_nothing: \prg_do_nothing: X - \exp_after:wN \@@_generate_internal_test:Nw \exp_after:wN ##2 - \else: - \exp_after:wN \@@_generate_internal_test_aux:w \exp_after:wN #1 - \fi: - ##3 - \s_@@_mark - { - \use:e - { - ##1 { exp_args:N ##3 } - { \@@_generate_internal_variant_loop:n ##3 { : \use_i:nn } } - } - } - #1 - \s_@@_mark - { \exp_not:n { \@@_generate_internal_one_go:NNn ##1 ##2 {##3} } } - \s_@@_stop - } - \cs_new_protected:Npn \@@_generate_internal_test_aux:w - ##1 #1 ##2 \s_@@_mark ##3 ##4 \s_@@_stop {##3} - \cs_new_eq:NN \@@_generate_internal_test:Nw - \@@_generate_internal_test_aux:w - } -\exp_args:No \@@_tmp:w { \token_to_str:N p } -\cs_new_protected:Npn \@@_generate_internal_one_go:NNn #1#2#3 - { - \@@_generate_internal_loop:nwnnw - { \exp_not:N ##1 } 1 . { } { } - #3 { ? \@@_generate_internal_end:w } X ; - 23456789 { ? \@@_generate_internal_long:w } ; - #1 #2 {#3} - } -\cs_new_protected:Npn \@@_generate_internal_loop:nwnnw #1#2 . #3#4#5#6 ; #7 - { - \use_none:n #5 - \use_none:n #7 - \cs_if_exist_use:cF { @@_generate_internal_#5:NN } - { \@@_generate_internal_other:NN } - #5 #7 - #7 . - { #3 #1 } { #4 ## #2 } - #6 ; - } -\cs_new_protected:Npn \@@_generate_internal_N:NN #1#2 - { \@@_generate_internal_loop:nwnnw { \exp_not:N ###2 } } -\cs_new_protected:Npn \@@_generate_internal_c:NN #1#2 - { \exp_args:No \@@_generate_internal_loop:nwnnw { \exp_not:c {###2} } } -\cs_new_protected:Npn \@@_generate_internal_n:NN #1#2 - { \@@_generate_internal_loop:nwnnw { { \exp_not:n {###2} } } } -\cs_new_protected:Npn \@@_generate_internal_x:NN #1#2 - { \@@_generate_internal_loop:nwnnw { {###2} } } -\cs_new_protected:Npn \@@_generate_internal_other:NN #1#2 - { - \exp_args:No \@@_generate_internal_loop:nwnnw - { - \exp_after:wN - { - \exp:w \exp_args:NNc \exp_after:wN \exp_end: - { exp_not:#1 } {###2} - } - } - } -\cs_new_protected:Npn \@@_generate_internal_end:w #1 . #2#3#4 ; #5 ; #6#7#8 - { #6 { exp_args:N #8 } #3 { #7 {#2} } } -\cs_new_protected:Npn \@@_generate_internal_long:w #1 N #2#3 . #4#5#6# - { - \exp_args:Nx \@@_generate_internal_long:nnnNNn - { \@@_generate_internal_variant_loop:n #2 #6 { : \use_i:nn } } - {#4} {#5} - } -\cs_new:Npn \@@_generate_internal_long:nnnNNn #1#2#3#4 ; ; #5#6#7 - { #5 { exp_args:N #7 } #3 { #6 { \exp_not:n {#1} {#2} } } } -% \end{macrocode} -% This command grabs char by char outputting |\::#1| (not expanded -% further). We avoid tests by putting a trailing |: \use_i:nn|, which -% leaves \cs{cs_end:} and removes the looping macro. The colon is in -% fact also turned into \cs{:::} so that the required structure for -% |\exp_args:N...| commands is correctly terminated. -% \begin{macrocode} -\cs_new:Npn \@@_generate_internal_variant_loop:n #1 - { - \exp_after:wN \exp_not:N \cs:w :: #1 \cs_end: - \@@_generate_internal_variant_loop:n - } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro} -% { -% \prg_generate_conditional_variant:Nnn, -% \@@_generate_variant:nnNnn, -% \@@_generate_variant:w, -% \@@_generate_variant:n, -% \@@_generate_variant_p_form:nnn, -% \@@_generate_variant_T_form:nnn, -% \@@_generate_variant_F_form:nnn, -% \@@_generate_variant_TF_form:nnn, -% } -% \begin{macrocode} -\cs_new_protected:Npn \prg_generate_conditional_variant:Nnn #1 - { - \use:e - { - \@@_generate_variant:nnNnn - \cs_split_function:N #1 - } - } -\cs_new_protected:Npn \@@_generate_variant:nnNnn #1#2#3#4#5 - { - \if_meaning:w \c_false_bool #3 - \msg_error:nne { kernel } { missing-colon } - { \token_to_str:c {#1} } - \@@_use_i_delimit_by_s_stop:nw - \fi: - \exp_after:wN \@@_generate_variant:w - \tl_to_str:n {#5} , \scan_stop: , \q_@@_recursion_stop - \@@_use_none_delimit_by_s_stop:w \s_@@_mark {#1} {#2} {#4} \s_@@_stop - } -\cs_new_protected:Npn \@@_generate_variant:w - #1 , #2 \s_@@_mark #3#4#5 - { - \if_meaning:w \scan_stop: #1 \scan_stop: - \if_meaning:w \q_@@_nil #1 \q_@@_nil - \use_i:nnn - \fi: - \exp_after:wN \@@_use_none_delimit_by_q_recursion_stop:w - \else: - \cs_if_exist_use:cTF { @@_generate_variant_#1_form:nnn } - { {#3} {#4} {#5} } - { - \msg_error:nnee - { kernel } { conditional-form-unknown } - {#1} { \token_to_str:c { #3 : #4 } } - } - \fi: - \@@_generate_variant:w #2 \s_@@_mark {#3} {#4} {#5} - } -\cs_new_protected:Npn \@@_generate_variant_p_form:nnn #1#2 - { \cs_generate_variant:cn { #1 _p : #2 } } -\cs_new_protected:Npn \@@_generate_variant_T_form:nnn #1#2 - { \cs_generate_variant:cn { #1 : #2 T } } -\cs_new_protected:Npn \@@_generate_variant_F_form:nnn #1#2 - { \cs_generate_variant:cn { #1 : #2 F } } -\cs_new_protected:Npn \@@_generate_variant_TF_form:nnn #1#2 - { \cs_generate_variant:cn { #1 : #2 TF } } -% \end{macrocode} -% \end{macro} -% -% \begin{macro}{\exp_args_generate:n} -% This function is not used in the kernel hence we can use functions -% that are defined in later modules. It also does not need to be fast -% so use inline mappings. For each requested variant we check that -% there are no characters besides |NnpcofVvx|, in particular that -% there are no spaces. Then we just call the internal function. -% \begin{macrocode} -\cs_new_protected:Npn \exp_args_generate:n #1 - { - \exp_args:No \clist_map_inline:nn { \tl_to_str:n {#1} } - { - \str_map_inline:nn {##1} - { - \str_if_in:nnF { NnpcofeVvx } {####1} - { - \msg_error:nnnn { kernel } { invalid-exp-args } - {####1} {##1} - \str_map_break:n { \use_none:nn } - } - } - \@@_generate_internal_variant:n {##1} - } - } -% \end{macrocode} -% \end{macro} -% -% \subsection{Definitions with the automated technique} -% \label{sec:l3expan:gendef} -% -% Some of these could be done more efficiently, but the complexity of -% coding then becomes an issue. Notice that the auto-generated functions -% actually take no arguments themselves. -% -% \begin{macro}[EXP] -% { -% \exp_args:Nnc, \exp_args:Nno, \exp_args:NnV, \exp_args:Nnv, \exp_args:Nne, \exp_args:Nnf, -% \exp_args:Noc, \exp_args:Noo, \exp_args:Nof, -% \exp_args:NVo, \exp_args:Nfo, \exp_args:Nff, \exp_args:Nee -% } -% \begin{macro} -% { -% \exp_args:NNx, \exp_args:Ncx, \exp_args:Nnx, -% \exp_args:Nox, \exp_args:Nxo, \exp_args:Nxx, -% } -% Here are the actual function definitions, using the helper -% functions above. The group is used because -% \cs{@@_generate_internal_variant:n} redefines \cs{@@_tmp:w} locally. -% \begin{macrocode} -\cs_set_protected:Npn \@@_tmp:w #1 - { - \group_begin: - \exp_args:No \@@_generate_internal_variant:n - { \tl_to_str:n {#1} } - \group_end: - } -\@@_tmp:w { nc } -\@@_tmp:w { no } -\@@_tmp:w { nV } -\@@_tmp:w { nv } -\@@_tmp:w { ne } -\@@_tmp:w { nf } -\@@_tmp:w { oc } -\@@_tmp:w { oo } -\@@_tmp:w { of } -\@@_tmp:w { Vo } -\@@_tmp:w { fo } -\@@_tmp:w { ff } -\@@_tmp:w { ee } -\@@_tmp:w { Nx } -\@@_tmp:w { cx } -\@@_tmp:w { nx } -\@@_tmp:w { ox } -\@@_tmp:w { xo } -\@@_tmp:w { xx } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macro}[EXP] -% { -% \exp_args:NNcf, -% \exp_args:NNno, \exp_args:NNnV, \exp_args:NNoo, \exp_args:NNVV, -% \exp_args:Ncno, \exp_args:NcnV, \exp_args:Ncoo, \exp_args:NcVV, -% \exp_args:Nnnc, \exp_args:Nnno, \exp_args:Nnnf, \exp_args:Nnff, -% \exp_args:Nooo, \exp_args:Noof, \exp_args:Nffo, \exp_args:Neee -% } -% \begin{macro} -% { -% \exp_args:NNNx, \exp_args:NNnx, \exp_args:NNox, -% \exp_args:Nccx, \exp_args:Ncnx, -% \exp_args:Nnnx, \exp_args:Nnox, \exp_args:Noox, -% } -% \begin{macrocode} -\@@_tmp:w { Ncf } -\@@_tmp:w { Nno } -\@@_tmp:w { NnV } -\@@_tmp:w { Noo } -\@@_tmp:w { NVV } -\@@_tmp:w { cno } -\@@_tmp:w { cnV } -\@@_tmp:w { coo } -\@@_tmp:w { cVV } -\@@_tmp:w { nnc } -\@@_tmp:w { nno } -\@@_tmp:w { nnf } -\@@_tmp:w { nff } -\@@_tmp:w { ooo } -\@@_tmp:w { oof } -\@@_tmp:w { ffo } -\@@_tmp:w { eee } -\@@_tmp:w { NNx } -\@@_tmp:w { Nnx } -\@@_tmp:w { Nox } -\@@_tmp:w { nnx } -\@@_tmp:w { nox } -\@@_tmp:w { ccx } -\@@_tmp:w { cnx } -\@@_tmp:w { oox } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \subsection{Held-over variant generation} -% -% \begin{macro}[documented-as = \cs_generate_from_arg_count:NNnn] -% {\cs_generate_from_arg_count:NNno} -% \begin{macro}[documented-as = \cs_replacement_spec:N]{\cs_replacement_spec:c} -% A couple of variants that are from early functions. -% \begin{macrocode} -\cs_generate_variant:Nn \cs_generate_from_arg_count:NNnn { NNno } -\cs_generate_variant:Nn \cs_replacement_spec:N { c } -% \end{macrocode} -% \end{macro} -% \end{macro} -% -% \begin{macrocode} -%</package> -% \end{macrocode} -% -% \end{implementation} -% -% \PrintIndex |