% \iffalse meta-comment % %% File: l3tl.dtx Copyright (C) 1990-2012 The LaTeX3 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 %% %% http://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 released version of this bundle is available from CTAN. %% %% ----------------------------------------------------------------------- %% %% The development version of the bundle can be found at %% %% http://www.latex-project.org/svnroot/experimental/trunk/ %% %% for those people who are interested. %% %%%%%%%%%%% %% NOTE: %% %%%%%%%%%%% %% %% Snapshots taken from the repository represent work in progress and may %% not work or may contain conflicting material! We therefore ask %% people _not_ to put them into distributions, archives, etc. without %% prior consultation with the LaTeX3 Project. %% %% ----------------------------------------------------------------------- % %<*driver|package> \RequirePackage{l3bootstrap} \GetIdInfo$Id: l3tl.dtx 4339 2012-11-24 19:16:43Z joseph $ {L3 Token lists} % %<*driver> \documentclass[full]{l3doc} \begin{document} \DocInput{\jobname.dtx} \end{document} % % \fi % % \title{^^A % The \pkg{l3tl} package\\ Token lists^^A % \thanks{This file describes v\ExplFileVersion, % last revised \ExplFileDate.}^^A % } % % \author{^^A % The \LaTeX3 Project\thanks % {^^A % E-mail: % \href{mailto:latex-team@latex-project.org} % {latex-team@latex-project.org}^^A % }^^A % } % % \date{Released \ExplFileDate} % % \maketitle % % \begin{documentation} % % \TeX{} works with tokens, and \LaTeX3 therefore provides a number of % functions to deal with lists of tokens. Token lists may be present % directly in the argument to a function: % \begin{verbatim} % \foo:n { a collection of \tokens } % \end{verbatim} % or may be stored in a so-called \enquote{token list variable}, which % have the suffix \texttt{tl}: a token list variable can also be used as % the argument to a function, for example % \begin{verbatim} % \foo:N \l_some_tl % \end{verbatim} % In both cases, functions are available to test an manipulate the lists % of tokens, and these have the module prefix \texttt{tl}. % In many cases, function which can be applied to token list variables % are paired with similar functions for application to explicit lists % of tokens: the two \enquote{views} of a token list are therefore collected % together here. % % A token list (explicit, or stored in a variable) can be seen either % as a list of \enquote{items}, % or a list of \enquote{tokens}. An item is whatever \cs{use:n} would % grab as its argument: a single non-space token or a brace group, % with optional leading explicit space characters (each item is thus % itself a token list). A token is either a normal \texttt{N} argument, % or \verb*| |, |{|, or |}| (assuming normal \TeX{} category codes). % Thus for example % \begin{verbatim} % { Hello } ~ world % \end{verbatim} % contains six items (\texttt{Hello}, \texttt{w}, \texttt{o}, \texttt{r}, % \texttt{l} and \texttt{d}), but thirteen tokens (|{|, \texttt{H}, \texttt{e}, % \texttt{l}, \texttt{l}, \texttt{o}, |}|, \verb*| |, \texttt{w}, \texttt{o}, % \texttt{r}, \texttt{l} and \texttt{d}). % Functions which act on items are often faster than their analogue acting % directly on tokens. % % ^^A todo: perhaps move to another module, l3token or l3basics? % \begin{texnote} % When \TeX{} fetches an undelimited argument from the input stream, % explicit character tokens with character code $32$ (space) and % category code $10$ (space), which we here call \enquote{explicit % space characters}, are ignored. If the following token is an % explicit character token with category code $1$ (begin-group) and an % arbitrary character code, then \TeX{} scans ahead to obtain an equal % number of explicit character tokens with category code $1$ % (begin-group) and $2$ (end-group), and the resulting list of tokens % (with outer braces removed) becomes the argument. Otherwise, a % single token is taken as the argument for the macro: we call such % single tokens \enquote{N-type}, as they are suitable to be used as % an argument for a function with the signature~\texttt{:N}. % % When \TeX{} reads a character of category code $10$ for the first % time, it is converted to an explicit space character, with character % code $32$, regardless of the initial character code. % \enquote{Funny} spaces with a different category code, can be % produced using \cs{tl_to_lowercase:n} or \cs{tl_to_uppercase:n}. % Explicit space characters are also produced as a result of % \cs{token_to_str:N}, \cs{tl_to_str:n}, etc. % \end{texnote} % % \section{Creating and initialising token list variables} % % \begin{function}{\tl_new:N, \tl_new:c} % \begin{syntax} % \cs{tl_new:N} \meta{tl~var} % \end{syntax} % Creates a new \meta{tl~var} or raises an error if the % name is already taken. The declaration is global. The % \meta{tl~var} will initially be empty. % \end{function} % % \begin{function}{\tl_const:Nn, \tl_const:Nx, \tl_const:cn, \tl_const:cx} % \begin{syntax} % \cs{tl_const:Nn} \meta{tl~var} \Arg{token list} % \end{syntax} % Creates a new constant \meta{tl~var} or raises an error % if the name is already taken. The value of the % \meta{tl~var} will be set globally to the % \meta{token list}. % \end{function} % % \begin{function}{\tl_clear:N, \tl_clear:c, \tl_gclear:N, \tl_gclear:c} % \begin{syntax} % \cs{tl_clear:N} \meta{tl~var} % \end{syntax} % Clears all entries from the \meta{tl~var} within the scope of % the current \TeX{} group. % \end{function} % % \begin{function} % {\tl_clear_new:N, \tl_clear_new:c, \tl_gclear_new:N, \tl_gclear_new:c} % \begin{syntax} % \cs{tl_clear_new:N} \meta{tl~var} % \end{syntax} % Ensures that the \meta{tl~var} exists globally by applying % \cs{tl_new:N} if necessary, then applies \cs{tl_(g)clear:N} to leave % the \meta{tl~var} empty. % \end{function} % % \begin{function} % { % \tl_set_eq:NN, \tl_set_eq:cN, \tl_set_eq:Nc, \tl_set_eq:cc, % \tl_gset_eq:NN, \tl_gset_eq:cN, \tl_gset_eq:Nc, \tl_gset_eq:cc % } % \begin{syntax} % \cs{tl_set_eq:NN} \meta{tl~var_1} \meta{tl~var_2} % \end{syntax} % Sets the content of \meta{tl~var_1} equal to that of % \meta{tl~var_2}. % \end{function} % % \begin{function}[added = 2012-05-18] % { % \tl_concat:NNN, \tl_concat:ccc, % \tl_gconcat:NNN, \tl_gconcat:ccc % } % \begin{syntax} % \cs{tl_concat:NNN} \meta{tl~var_1} \meta{tl~var_2} \meta{tl~var_3} % \end{syntax} % Concatenates the content of \meta{tl~var_2} and \meta{tl~var_3} % together and saves the result in \meta{tl~var_1}. The \meta{tl~var_2} % will be placed at the left side of the new token list. % \end{function} % % \begin{function}[EXP, pTF, added=2012-03-03]{\tl_if_exist:N, \tl_if_exist:c} % \begin{syntax} % \cs{tl_if_exist_p:N} \meta{tl~var} % \cs{tl_if_exist:NTF} \meta{tl~var} \Arg{true code} \Arg{false code} % \end{syntax} % Tests whether the \meta{tl~var} is currently defined. This does not % check that the \meta{tl~var} really is a token list variable. % \end{function} % % \section{Adding data to token list variables} % % \begin{function} % { % \tl_set:Nn, \tl_set:NV, \tl_set:Nv, \tl_set:No, \tl_set:Nf, \tl_set:Nx, % \tl_set:cn, \tl_set:cV, \tl_set:cv, \tl_set:co, \tl_set:cf, \tl_set:cx, % \tl_gset:Nn, \tl_gset:NV, \tl_gset:Nv, % \tl_gset:No, \tl_gset:Nf, \tl_gset:Nx, % \tl_gset:cn, \tl_gset:cV, \tl_gset:cv, % \tl_gset:co, \tl_gset:cf, \tl_gset:cx % } % \begin{syntax} % \cs{tl_set:Nn} \meta{tl~var} \Arg{tokens} % \end{syntax} % Sets \meta{tl~var} to contain \meta{tokens}, % removing any previous content from the variable. % \end{function} % % \begin{function} % { % \tl_put_left:Nn, \tl_put_left:NV, \tl_put_left:No, \tl_put_left:Nx, % \tl_put_left:cn, \tl_put_left:cV, \tl_put_left:co, \tl_put_left:cx, % \tl_gput_left:Nn, \tl_gput_left:NV, \tl_gput_left:No, \tl_gput_left:Nx, % \tl_gput_left:cn, \tl_gput_left:cV, \tl_gput_left:co, \tl_gput_left:cx % } % \begin{syntax} % \cs{tl_put_left:Nn} \meta{tl~var} \Arg{tokens} % \end{syntax} % Appends \meta{tokens} to the left side of the current content of % \meta{tl~var}. % \end{function} % % \begin{function} % { % \tl_put_right:Nn, \tl_put_right:NV, \tl_put_right:No, \tl_put_right:Nx, % \tl_put_right:cn, \tl_put_right:cV, \tl_put_right:co, \tl_put_right:cx, % \tl_gput_right:Nn, \tl_gput_right:NV, \tl_gput_right:No, % \tl_gput_right:Nx, % \tl_gput_right:cn, \tl_gput_right:cV, \tl_gput_right:co, % \tl_gput_right:cx % } % \begin{syntax} % \cs{tl_put_right:Nn} \meta{tl~var} \Arg{tokens} % \end{syntax} % Appends \meta{tokens} to the right side of the current content of % \meta{tl~var}. % \end{function} % % \section{Modifying token list variables} % % \begin{function}[updated = 2011-08-11] % { % \tl_replace_once:Nnn, \tl_replace_once:cnn, % \tl_greplace_once:Nnn, \tl_greplace_once:cnn % } % \begin{syntax} % \cs{tl_replace_once:Nnn} \meta{tl~var} \Arg{old tokens} \Arg{new tokens} % \end{syntax} % Replaces the first (leftmost) occurrence of \meta{old tokens} in the % \meta{tl~var} with \meta{new tokens}. \meta{Old tokens} % cannot contain |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % \end{function} % % \begin{function}[updated = 2011-08-11] % { % \tl_replace_all:Nnn, \tl_replace_all:cnn, % \tl_greplace_all:Nnn, \tl_greplace_all:cnn % } % \begin{syntax} % \cs{tl_replace_all:Nnn} \meta{tl~var} \Arg{old tokens} \Arg{new tokens} % \end{syntax} % Replaces all occurrences of \meta{old tokens} in the % \meta{tl~var} with \meta{new tokens}. \meta{Old tokens} % cannot contain |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % As this function % operates from left to right, the pattern \meta{old tokens} % may remain after the replacement (see \cs{tl_remove_all:Nn} % for an example). % \end{function} % % \begin{function}[updated = 2011-08-11] % { % \tl_remove_once:Nn, \tl_remove_once:cn, % \tl_gremove_once:Nn, \tl_gremove_once:cn % } % \begin{syntax} % \cs{tl_remove_once:Nn} \meta{tl~var} \Arg{tokens} % \end{syntax} % Removes the first (leftmost) occurrence of \meta{tokens} from the % \meta{tl~var}. \meta{Tokens} cannot contain |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % \end{function} % % \begin{function}[updated = 2011-08-11] % { % \tl_remove_all:Nn, \tl_remove_all:cn, % \tl_gremove_all:Nn, \tl_gremove_all:cn % } % \begin{syntax} % \cs{tl_remove_all:Nn} \meta{tl~var} \Arg{tokens} % \end{syntax} % Removes all occurrences of \meta{tokens} from the % \meta{tl~var}. \meta{Tokens} cannot contain |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % As this function % operates from left to right, the pattern \meta{tokens} % may remain after the removal, for instance, % \begin{quote} % \cs{tl_set:Nn} \cs{l_tmpa_tl} |{abbccd}| % \cs{tl_remove_all:Nn} \cs{l_tmpa_tl} |{bc}| % \end{quote} % will result in \cs{l_tmpa_tl} containing \texttt{abcd}. % \end{function} % % \section{Reassigning token list category codes} % % \begin{function}[updated = 2011-12-18] % { % \tl_set_rescan:Nnn, \tl_set_rescan:Nno, \tl_set_rescan:Nnx, % \tl_set_rescan:cnn, \tl_set_rescan:cno, \tl_set_rescan:cnx, % \tl_gset_rescan:Nnn, \tl_gset_rescan:Nno, \tl_gset_rescan:Nnx, % \tl_gset_rescan:cnn, \tl_gset_rescan:cno, \tl_gset_rescan:cnx % } % \begin{syntax} % \cs{tl_set_rescan:Nnn} \meta{tl~var} \Arg{setup} \Arg{tokens} % \end{syntax} % Sets \meta{tl~var} to contain \meta{tokens}, % applying the category code r{\'e}gime specified in the % \meta{setup} before carrying out the assignment. This allows the % \meta{tl~var} to contain material with category codes % other than those that apply when \meta{tokens} are absorbed. See also % \cs{tl_rescan:nn}. % \end{function} % % \begin{function}[updated = 2011-12-18]{\tl_rescan:nn} % \begin{syntax} % \cs{tl_rescan:nn} \Arg{setup} \Arg{tokens} % \end{syntax} % Rescans \meta{tokens} applying the category code r\'egime specified % in the \meta{setup}, and leaves the resulting tokens in the input % stream. See also \cs{tl_set_rescan:Nnn}. % \end{function} % % \section{Reassigning token list character codes} % % \begin{function}[updated = 2012-09-08]{\tl_to_lowercase:n} % \begin{syntax} % \cs{tl_to_lowercase:n} \Arg{tokens} % \end{syntax} % Works through all of the \meta{tokens}, replacing each character token % with the lower case equivalent as defined by \cs{char_set_lccode:nn}. % Characters with no defined lower case character code are left % unchanged. This process does not alter the category code assigned % to the \meta{tokens}. % \begin{texnote} % This is a wrapper around the \TeX{} primitive \tn{lowercase}. % \end{texnote} % \end{function} % % \begin{function}[updated = 2012-09-08]{\tl_to_uppercase:n} % \begin{syntax} % \cs{tl_to_uppercase:n} \Arg{tokens} % \end{syntax} % Works through all of the \meta{tokens}, replacing each character token % with the upper case equivalent as defined by \cs{char_set_uccode:nn}. % Characters with no defined upper case character code are left % unchanged. This process does not alter the category code assigned % to the \meta{tokens}. % \begin{texnote} % This is a wrapper around the \TeX{} primitive \tn{uppercase}. % \end{texnote} % \end{function} % % \section{Token list conditionals} % % \begin{function}[EXP,pTF]{\tl_if_blank:n, \tl_if_blank:V, \tl_if_blank:o} % \begin{syntax} % \cs{tl_if_blank_p:n} \Arg{token list} % \cs{tl_if_blank:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the \meta{token list} consists only of blank spaces % (\emph{i.e.}~contains no item). The test is \texttt{true} if % \meta{token list} is zero or more explicit space characters % (explicit tokens with character code~$32$ and category code~$10$), % and is \texttt{false} otherwise. % \end{function} % % \begin{function}[EXP,pTF]{\tl_if_empty:N, \tl_if_empty:c} % \begin{syntax} % \cs{tl_if_empty_p:N} \meta{tl~var} % \cs{tl_if_empty:NTF} \meta{tl~var} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the \meta{token list variable} is entirely empty % (\emph{i.e.}~contains no tokens at all). % \end{function} % % \begin{function}[added = 2012-05-24, updated = 2012-06-05, EXP,pTF] % {\tl_if_empty:n, \tl_if_empty:V, \tl_if_empty:o} % \begin{syntax} % \cs{tl_if_empty_p:n} \Arg{token list} % \cs{tl_if_empty:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the \meta{token list} is entirely empty % (\emph{i.e.}~contains no tokens at all). % \end{function} % % \begin{function}[EXP,pTF] % {\tl_if_eq:NN, \tl_if_eq:Nc, \tl_if_eq:cN, \tl_if_eq:cc} % \begin{syntax} % \cs{tl_if_eq_p:NN} \Arg{tl~var_1} \Arg{tl~var_2} % \cs{tl_if_eq:NNTF} \Arg{tl~var_1} \Arg{tl~var_2} \Arg{true code} \Arg{false code} % \end{syntax} % Compares the content of two \meta{token list variables} and % is logically \texttt{true} if the two contain the same list of % tokens (\emph{i.e.}~identical in both the list of characters they % contain and the category codes of those characters). Thus for example % \begin{verbatim} % \tl_set:Nn \l_tmpa_tl { abc } % \tl_set:Nx \l_tmpb_tl { \tl_to_str:n { abc } } % \tl_if_eq:NNTF \l_tmpa_tl \l_tmpb_tl { true } { false } % \end{verbatim} % yields \texttt{false}. % \end{function} % % \begin{function}[TF]{\tl_if_eq:nn} % \begin{syntax} % \cs{tl_if_eq:nnTF} \meta{token list_1} \Arg{token list_2} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if \meta{token list_1} and \meta{token list_2} contain the % same list of tokens, both in respect of character codes and category % codes. % \end{function} % % \begin{function}[TF]{\tl_if_in:Nn, \tl_if_in:cn} % \begin{syntax} % \cs{tl_if_in:NnTF} \meta{tl~var} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the \meta{token list} is found in the content of the % \meta{tl~var}. The \meta{token list} cannot contain % the tokens |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % \end{function} % % \begin{function}[TF] % {\tl_if_in:nn, \tl_if_in:Vn, \tl_if_in:on, \tl_if_in:no} % \begin{syntax} % \cs{tl_if_in:nnTF} \Arg{token list_1} \Arg{token list_2} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if \meta{token list_2} is found inside \meta{token list_1}. % The \meta{token list_2} cannot contain the tokens |{|, |}| or |#| % (more precisely, explicit character tokens with category code $1$ % (begin-group) or $2$ (end-group), and tokens with category code $6$). % \end{function} % % \begin{function}[updated = 2011-08-13, EXP,pTF] % {\tl_if_single:N, \tl_if_single:c} % \begin{syntax} % \cs{tl_if_single_p:N} \Arg{tl~var} % \cs{tl_if_single:NTF} \Arg{tl~var} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the content of the \meta{tl~var} consists of a single item, % \emph{i.e.}~is a single normal token (neither an explicit space % character nor a begin-group character) or a single brace group, % surrounded by optional spaces on both sides. In other words, such a % token list has token count $1$ according to \cs{tl_count:N}. % \end{function} % % \begin{function}[updated = 2011-08-13, EXP,pTF]{\tl_if_single:n} % \begin{syntax} % \cs{tl_if_single_p:n} \Arg{token list} % \cs{tl_if_single:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the \meta{token list} has exactly one item, \emph{i.e.}~is % a single normal token (neither an explicit space character nor a % begin-group character) or a single brace group, surrounded by % optional spaces on both sides. In other words, such a token list has % token count $1$ according to \cs{tl_count:n}. % \end{function} % % \begin{function}[added = 2012-06-03, EXP]{\tl_case:Nnn, \tl_case:cnn} % \begin{syntax} % \cs{tl_case:Nnn} \meta{test token list variable} \\ % ~~"{" \\ % ~~~~\meta{token list variable case_1} \Arg{code case_1} \\ % ~~~~\meta{token list variable case_2} \Arg{code case_2} \\ % ~~~~\ldots \\ % ~~~~\meta{token list variable case_n} \Arg{code case_n} \\ % ~~"}" \\ % ~~\Arg{else code} % \end{syntax} % This function compares the \meta{test token list variable} in turn % with each of the \meta{token list variable cases}. If the two % are equal (as described for \cs{tl_if_eq:NNTF}) % then the associated \meta{code} is left in the input % stream. If none of the tests are \texttt{true} then the % \texttt{else code} will be left in the input stream. % \end{function} % % \section{Mapping to token lists} % % \begin{function}[updated = 2012-06-29, rEXP] % {\tl_map_function:NN, \tl_map_function:cN} % \begin{syntax} % \cs{tl_map_function:NN} \meta{tl~var} \meta{function} % \end{syntax} % Applies \meta{function} to every \meta{item} in the \meta{tl~var}. % The \meta{function} will receive one argument for each iteration. % This may be a number of tokens if the \meta{item} was stored within % braces. Hence the \meta{function} should anticipate receiving % \texttt{n}-type arguments. See also \cs{tl_map_function:nN}. % \end{function} % % \begin{function}[updated = 2012-06-29, rEXP]{\tl_map_function:nN} % \begin{syntax} % \cs{tl_map_function:nN} \meta{token list} \meta{function} % \end{syntax} % Applies \meta{function} to every \meta{item} in the \meta{token list}, % The \meta{function} will receive one argument for each iteration. % This may be a number of tokens if the \meta{item} was stored within % braces. Hence the \meta{function} should anticipate receiving % \texttt{n}-type arguments. See also \cs{tl_map_function:NN}. % \end{function} % % \begin{function}[updated = 2012-06-29] % {\tl_map_inline:Nn, \tl_map_inline:cn} % \begin{syntax} % \cs{tl_map_inline:Nn} \meta{tl~var} \Arg{inline function} % \end{syntax} % Applies the \meta{inline function} to every \meta{item} stored within the % \meta{tl~var}. The \meta{inline function} should consist of code which % will receive the \meta{item} as |#1|. One in line mapping can be nested % inside another. See also \cs{tl_map_function:NN}. % \end{function} % % \begin{function}[updated = 2012-06-29]{\tl_map_inline:nn} % \begin{syntax} % \cs{tl_map_inline:nn} \meta{token list} \Arg{inline function} % \end{syntax} % Applies the \meta{inline function} to every \meta{item} stored within the % \meta{token list}. The \meta{inline function} should consist of code which % will receive the \meta{item} as |#1|. One in line mapping can be nested % inside another. See also \cs{tl_map_function:nN}. % \end{function} % % \begin{function}[updated = 2012-06-29] % {\tl_map_variable:NNn, \tl_map_variable:cNn} % \begin{syntax} % \cs{tl_map_variable:NNn} \meta{tl~var} \meta{variable} \Arg{function} % \end{syntax} % Applies the \meta{function} to every \meta{item} stored % within the \meta{tl~var}. The \meta{function} should consist of code % which will receive the \meta{item} stored in the \meta{variable}. % One variable mapping can be nested inside another. See also % \cs{tl_map_inline:Nn}. % \end{function} % % \begin{function}[updated = 2012-06-29]{\tl_map_variable:nNn} % \begin{syntax} % \cs{tl_map_variable:nNn} \meta{token list} \meta{variable} \Arg{function} % \end{syntax} % Applies the \meta{function} to every \meta{item} stored % within the \meta{token list}. The \meta{function} should consist of code % which will receive the \meta{item} stored in the \meta{variable}. % One variable mapping can be nested inside another. See also % \cs{tl_map_inline:nn}. % \end{function} % % \begin{function}[updated = 2012-06-29, rEXP]{\tl_map_break:} % \begin{syntax} % \cs{tl_map_break:} % \end{syntax} % Used to terminate a \cs{tl_map_\ldots} function before all % entries in the \meta{token list variable} have been processed. This % will normally take place within a conditional statement, for example % \begin{verbatim} % \tl_map_inline:Nn \l_my_tl % { % \str_if_eq:nnT { #1 } { bingo } { \tl_map_break: } % % Do something useful % } % \end{verbatim} % See also \cs{tl_map_break:n}. % Use outside of a \cs{tl_map_\ldots} scenario will lead to low % level \TeX{} errors. % \begin{texnote} % When the mapping is broken, additional tokens may be inserted by the % internal macro \cs{__prg_break_point:Nn} before the \meta{tokens} are % inserted into the input stream. % This will depend on the design of the mapping function. % \end{texnote} % \end{function} % % \begin{function}[updated = 2012-06-29, rEXP]{\tl_map_break:n} % \begin{syntax} % \cs{tl_map_break:n} \Arg{tokens} % \end{syntax} % Used to terminate a \cs{tl_map_\ldots} function before all % entries in the \meta{token list variable} have been processed, inserting % the \meta{tokens} after the mapping has ended. This will % normally take place within a conditional statement, for example % \begin{verbatim} % \tl_map_inline:Nn \l_my_tl % { % \str_if_eq:nnT { #1 } { bingo } % { \tl_map_break:n { } } % % Do something useful % } % \end{verbatim} % Use outside of a \cs{tl_map_\ldots} scenario will lead to low % level \TeX{} errors. % \begin{texnote} % When the mapping is broken, additional tokens may be inserted by the % internal macro \cs{__prg_break_point:Nn} before the \meta{tokens} are % inserted into the input stream. % This will depend on the design of the mapping function. % \end{texnote} % \end{function} % % \section{Using token lists} % % \begin{function}[EXP]{\tl_to_str:N, \tl_to_str:c} % \begin{syntax} % \cs{tl_to_str:N} \meta{tl~var} % \end{syntax} % Converts the content of the \meta{tl~var} into a series of characters % with category code $12$ (other) with the exception of spaces, which % retain category code $10$ (space). This \meta{string} is then left % in the input stream. % \end{function} % % \begin{function}[EXP]{\tl_to_str:n} % \begin{syntax} % \cs{tl_to_str:n} \Arg{tokens} % \end{syntax} % Converts the given \meta{tokens} into a series of characters with % category code $12$ (other) with the exception of spaces, which % retain category code $10$ (space). This \meta{string} is then left % in the input stream. Note that this function requires only a single % expansion. % \begin{texnote} % This is the \eTeX{} primitive \tn{detokenize}. Hence its argument % \emph{must} be given within braces. % \end{texnote} % \end{function} % % \begin{function}[EXP]{\tl_use:N, \tl_use:c} % \begin{syntax} % \cs{tl_use:N} \meta{tl~var} % \end{syntax} % Recovers the content of a \meta{tl~var} and places it % directly in the input stream. An error will be raised if the variable % does not exist or if it is invalid. Note that it is possible to use % a \meta{tl~var} directly without an accessor function. % \end{function} % % \section{Working with the content of token lists} % % \begin{function}[added = 2012-05-13, EXP] % {\tl_count:n, \tl_count:V, \tl_count:o} % \begin{syntax} % \cs{tl_count:n} \Arg{tokens} % \end{syntax} % Counts the number of \meta{items} in \meta{tokens} and leaves this % information in the input stream. Unbraced tokens count as one % element as do each token group (|{|\ldots|}|). This process will % ignore any unprotected spaces within \meta{tokens}. See also % \cs{tl_count:N}. This function requires three expansions, % giving an \meta{integer denotation}. % \end{function} % % \begin{function}[added = 2012-05-13, EXP]{\tl_count:N, \tl_count:c} % \begin{syntax} % \cs{tl_count:N} \Arg{tl~var} % \end{syntax} % Counts the number of token groups in the \meta{tl~var} % and leaves this information in the input stream. Unbraced tokens % count as one element as do each token group (|{|\ldots|}|). This % process will ignore any unprotected spaces within the \meta{tl~var}. % See also \cs{tl_count:n}. This function requires three expansions, % giving an \meta{integer denotation}. % \end{function} % % \begin{function}[updated = 2012-01-08, EXP] % {\tl_reverse:n, \tl_reverse:V, \tl_reverse:o} % \begin{syntax} % \cs{tl_reverse:n} \Arg{token list} % \end{syntax} % Reverses the order of the \meta{items} in the \meta{token list}, % so that \meta{item_1}\meta{item_2}\meta{item_3} \ldots \meta{item_n} % becomes \meta{item_n}\ldots \meta{item_3}\meta{item_2}\meta{item_1}. % This process will preserve unprotected space within the % \meta{token list}. Tokens are not reversed within braced token % groups, which keep their outer set of braces. % In situations where performance is important, % consider \cs{tl_reverse_items:n}. % See also \cs{tl_reverse:N}. % \begin{texnote} % The result is returned within \tn{exp_not:n}, which means that the token % list will not expand further when appearing in an \texttt{x}-type % argument expansion. % \end{texnote} % \end{function} % % \begin{function}[updated = 2012-01-08] % {\tl_reverse:N, \tl_reverse:c, \tl_greverse:N, \tl_greverse:c} % \begin{syntax} % \cs{tl_reverse:N} \Arg{tl~var} % \end{syntax} % Reverses the order of the \meta{items} stored in \meta{tl~var}, so % that \meta{item_1}\meta{item_2}\meta{item_3} \ldots \meta{item_n} % becomes \meta{item_n}\ldots \meta{item_3}\meta{item_2}\meta{item_1}. % This process will preserve unprotected spaces within the % \meta{token list variable}. Braced token groups are copied without % reversing the order of tokens, but keep the outer set of braces. % See also \cs{tl_reverse:n}, and, for improved performance, % \cs{tl_reverse_items:n}. % \end{function} % % \begin{function}[added = 2012-01-08, EXP]{\tl_reverse_items:n} % \begin{syntax} % \cs{tl_reverse_items:n} \Arg{token list} % \end{syntax} % Reverses the order of the \meta{items} stored in \meta{tl~var}, % so that \Arg{item_1}\Arg{item_2}\Arg{item_3} \ldots \Arg{item_n} % becomes \Arg{item_n} \ldots{} \Arg{item_3}\Arg{item_2}\Arg{item_1}. % This process will remove any unprotected space within the % \meta{token list}. Braced token groups are copied without % reversing the order of tokens, and keep the outer set of braces. % Items which are initially not braced are copied with braces in % the result. In cases where preserving spaces is important, % consider the slower function \cs{tl_reverse:n}. % \begin{texnote} % The result is returned within \tn{exp_not:n}, which means that the token % list will not expand further when appearing in an \texttt{x}-type % argument expansion. % \end{texnote} % \end{function} % % \begin{function}[added = 2011-07-09, updated = 2012-06-25, EXP] % {\tl_trim_spaces:n} % \begin{syntax} % \cs{tl_trim_spaces:n} \Arg{token list} % \end{syntax} % Removes any leading and trailing explicit space characters % (explicit tokens with character code~$32$ and category code~$10$) % from the \meta{token list} and leaves the result in the input % stream. % \begin{texnote} % The result is returned within \tn{exp_not:n}, which means that the token % list will not expand further when appearing in an \texttt{x}-type % argument expansion. % \end{texnote} % \end{function} % % \begin{function}[added = 2011-07-09] % { % \tl_trim_spaces:N, \tl_trim_spaces:c, % \tl_gtrim_spaces:N, \tl_gtrim_spaces:c % } % \begin{syntax} % \cs{tl_trim_spaces:N} \meta{tl~var} % \end{syntax} % Removes any leading and trailing explicit space characters % (explicit tokens with character code~$32$ and category code~$10$) % from the content of the \meta{tl~var}. % \end{function} % % \section{The first token from a token list} % % Functions which deal with either only the very first item (balanced % text or single normal token) in a token list, or the remaining tokens. % % \begin{function}[updated = 2012-09-09, EXP] % {\tl_head:N, \tl_head:n, \tl_head:V, \tl_head:v, \tl_head:f} % \begin{syntax} % \cs{tl_head:n} \Arg{token list} % \end{syntax} % Leaves in the input stream the first \meta{item} in the % \meta{token list}, discarding the rest of the \meta{token list}. % All leading explicit space characters % (explicit tokens with character code~$32$ and category code~$10$) % are discarded; for example % \begin{verbatim} % \tl_head:n { abc } % \end{verbatim} % and % \begin{verbatim} % \tl_head:n { ~ abc } % \end{verbatim} % will both leave |a| in the input stream. If the \enquote{head} is a % brace group, rather than a single token, the braces will be removed, and % so % \begin{verbatim} % \tl_head:n { ~ { ~ ab } c } % \end{verbatim} % yields \verb*| ab|. % A blank \meta{token list} (see \cs{tl_if_blank:nTF}) will result in % \cs{tl_head:n} leaving nothing in the input stream. % \begin{texnote} % The result is returned within \cs{exp_not:n}, which means that the token % list will not expand further when appearing in an \texttt{x}-type % argument expansion. % \end{texnote} % \end{function} % % \begin{function}[EXP]{\tl_head:w} % \begin{syntax} % \cs{tl_head:w} \meta{token list} | { } | \cs{q_stop} % \end{syntax} % Leaves in the input stream the first \meta{item} in the % \meta{token list}, discarding the rest of the \meta{token list}. % All leading explicit space characters % (explicit tokens with character code~$32$ and category code~$10$) % are discarded. % A blank \meta{token list} (which consists only of space characters) % will result in a low-level \TeX{} error, which may be avoided by the % inclusion of an empty group in the input (as shown), without the need % for an explicit test. Alternatively, \cs{tl_if_blank:nF} may be used to % avoid using the function with a \enquote{blank} argument. % This function requires only a single expansion, and thus is suitable for % use within an \texttt{o}-type expansion. In general, \cs{tl_head:n} should % be preferred if the number of expansions is not critical. % \end{function} % % \begin{function}[updated = 2012-09-01, EXP] % {\tl_tail:N, \tl_tail:n, \tl_tail:V, \tl_tail:v, \tl_tail:f} % \begin{syntax} % \cs{tl_tail:n} \Arg{token list} % \end{syntax} % Discards all leading explicit space characters % (explicit tokens with character code~$32$ and category code~$10$) % and the first \meta{item} in the \meta{token list}, and leaves the % remaining tokens in the input stream. Thus for example % \begin{verbatim} % \tl_tail:n { a ~ {bc} d } % \end{verbatim} % and % \begin{verbatim} % \tl_tail:n { ~ a ~ {bc} d } % \end{verbatim} % will both leave \verb*| {bc}d| in the input stream. A blank % \meta{token list} (see \cs{tl_if_blank:nTF}) will result % in \cs{tl_tail:n} leaving nothing in the input stream. % \begin{texnote} % The result is returned within \cs{exp_not:n}, which means that the % token list will not expand further when appearing in an \texttt{x}-type % argument expansion. % \end{texnote} % \end{function} % % \begin{function}[added = 2011-08-10, EXP]{\str_head:n,\str_tail:n} % \begin{syntax} % \cs{str_head:n} \Arg{token list} % \cs{str_tail:n} \Arg{token list} % \end{syntax} % Converts the \meta{token list} into a string, as described for % \cs{tl_to_str:n}. The \cs{str_head:n} function then leaves % the first character of this string in the input stream. % The \cs{str_tail:n} function leaves all characters except % the first in the input stream. The first character may be % a space. If the \meta{token list} argument is entirely empty, % nothing is left in the input stream. % \end{function} % % \begin{function}[updated = 2012-07-09, EXP, pTF]{\tl_if_head_eq_catcode:nN} % \begin{syntax} % \cs{tl_if_head_eq_catcode_p:nN} \Arg{token list} \meta{test token} % \cs{tl_if_head_eq_catcode:nNTF} \Arg{token list} \meta{test token} % ~~\Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} has the % same category code as the \meta{test token}. In the case where the % \meta{token list} is empty, the test will always be \texttt{false}. % \end{function} % % \begin{function}[updated = 2012-07-09, EXP, pTF] % {\tl_if_head_eq_charcode:nN, \tl_if_head_eq_charcode:fN} % \begin{syntax} % \cs{tl_if_head_eq_charcode_p:nN} \Arg{token list} \meta{test token} % \cs{tl_if_head_eq_charcode:nNTF} \Arg{token list} \meta{test token} % ~~\Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} has the % same character code as the \meta{test token}. In the case where the % \meta{token list} is empty, the test will always be \texttt{false}. % \end{function} % % \begin{function}[updated = 2012-07-09, EXP, pTF]{\tl_if_head_eq_meaning:nN} % \begin{syntax} % \cs{tl_if_head_eq_meaning_p:nN} \Arg{token list} \meta{test token} % \cs{tl_if_head_eq_meaning:nNTF} \Arg{token list} \meta{test token} % ~~\Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} has the % same meaning as the \meta{test token}. In the case where % \meta{token list} is empty, the test will always be \texttt{false}. % \end{function} % % \begin{function}[added = 2012-07-08, EXP, pTF]{\tl_if_head_is_group:n} % \begin{syntax} % \cs{tl_if_head_is_group_p:n} \Arg{token list} % \cs{tl_if_head_is_group:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} % is an explicit begin-group character (with category code~$1$ % and any character code), in other words, if the \meta{token list} % starts with a brace group. In particular, the test is \texttt{false} % if the \meta{token list} starts with an implicit token such as % \cs{c_group_begin_token}, or if it is empty. % This function is useful to implement actions on token lists on % a token by token basis. % \end{function} % % \begin{function}[added = 2012-07-08, EXP, pTF]{\tl_if_head_is_N_type:n} % \begin{syntax} % \cs{tl_if_head_is_N_type_p:n} \Arg{token list} % \cs{tl_if_head_is_N_type:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} % is a normal \texttt{N}-type argument. In other words, % it is neither an explicit space character % (explicit token with character code~$32$ and category code~$10$) % nor an explicit begin-group character % (with category code~1 and any character code). An empty % argument yields \texttt{false}, as it does not have a \enquote{normal} % first token. % This function is useful to implement actions on token lists on % a token by token basis. % \end{function} % % \begin{function}[updated = 2012-07-08, EXP, pTF]{\tl_if_head_is_space:n} % \begin{syntax} % \cs{tl_if_head_is_space_p:n} \Arg{token list} % \cs{tl_if_head_is_space:nTF} \Arg{token list} \Arg{true code} \Arg{false code} % \end{syntax} % Tests if the first \meta{token} in the \meta{token list} % is an explicit space character % (explicit token with character code~$12$ and category code~$10$). % In particular, the test is \texttt{false} if the \meta{token list} % starts with an implicit token such as \cs{c_space_token}, or if it % is empty. % This function is useful to implement actions on token lists on % a token by token basis. % \end{function} % % \section{Viewing token lists} % % \begin{function}[updated = 2012-09-09]{\tl_show:N, \tl_show:c} % \begin{syntax} % \cs{tl_show:N} \meta{tl~var} % \end{syntax} % Displays the content of the \meta{tl~var} on the terminal. % \begin{texnote} % This is similar to the \TeX{} primitive \tn{show}, wrapped to a % fixed number of characters per line. % \end{texnote} % \end{function} % % \begin{function}[updated = 2012-09-09]{\tl_show:n} % \begin{syntax} % \cs{tl_show:n} \meta{token list} % \end{syntax} % Displays the \meta{token list} on the terminal. % \begin{texnote} % This is similar to the \eTeX{} primitive \tn{showtokens}, wrapped % to a fixed number of characters per line. % \end{texnote} % \end{function} % % \section{Constant token lists} % % \begin{variable}{\c_empty_tl} % Constant that is always empty. % \end{variable} % % \begin{variable}[updated = 2011-08-18]{\c_job_name_tl} % Constant that gets the \enquote{job name} assigned when \TeX{} starts. % \begin{texnote} % This copies the contents of the primitive \tn{jobname}. It is a constant % that is set by \TeX{} and should not be overwritten by the package. % \end{texnote} % \end{variable} % % \begin{variable}{\c_space_tl} % An explicit space character contained in a token list (compare this with % \cs{c_space_token}). For use where an explicit space is required. % \end{variable} % % \section{Scratch token lists} % % \begin{variable}{\l_tmpa_tl, \l_tmpb_tl} % Scratch token lists for local assignment. These are never used by % the kernel code, and so are safe for use with any \LaTeX3-defined % function. However, they may be overwritten by other non-kernel % code and so should only be used for short-term storage. % \end{variable} % % \begin{variable}{\g_tmpa_tl, \g_tmpb_tl} % Scratch token lists for global assignment. These are never used by % the kernel code, and so are safe for use with any \LaTeX3-defined % function. However, they may be overwritten by other non-kernel % code and so should only be used for short-term storage. % \end{variable} % % \section{Internal functions} % % \begin{function}{\__tl_trim_spaces:nn} % \begin{syntax} % \cs{__tl_trim_spaces:nn} |{ \q_mark| \meta{token list} |}| \Arg{continuation} % \end{syntax} % This function removes all leading and trailing explicit space % characters from the \meta{token list}, and expands to the % \meta{continuation}, followed by a brace group containing % \cs{use_none:n} \cs{q_mark} \meta{trimmed token list}. For % instance, \cs{tl_trim_spaces:n} is implemented by taking the % \meta{continuation} to be \cs{exp_not:o}, and the \texttt{o}-type % expansion removes the \cs{q_mark}. This function is also used in % \pkg{l3clist} and \pkg{l3candidates}. % \end{function} % % \end{documentation} % % \begin{implementation} % % \section{\pkg{l3tl} implementation} % % \begin{macrocode} %<*initex|package> % \end{macrocode} % % \begin{macrocode} %<@@=tl> % \end{macrocode} % % \begin{macrocode} %<*package> \ProvidesExplPackage {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription} \__expl_package_check: % % \end{macrocode} % % A token list variable is a \TeX{} macro that holds tokens. By using the % \eTeX{} primitive \tn{unexpanded} inside a \TeX{} \tn{edef} it is % possible to store any tokens, including |#|, in this way. % % \subsection{Functions} % % \begin{macro}{\tl_new:N, \tl_new:c} % Creating new token list variables is a case of checking for an % existing definition and doing the definition. % \begin{macrocode} \cs_new_protected:Npn \tl_new:N #1 { \__chk_if_free_cs:N #1 \cs_gset_eq:NN #1 \c_empty_tl } \cs_generate_variant:Nn \tl_new:N { c } % \end{macrocode} % \end{macro} % % \begin{macro}{\tl_const:Nn, \tl_const:Nx, \tl_const:cn, \tl_const:cx} % Constants are also easy to generate. % \begin{macrocode} \cs_new_protected:Npn \tl_const:Nn #1#2 { \__chk_if_free_cs:N #1 \cs_gset_nopar:Npx #1 { \exp_not:n {#2} } } \cs_new_protected:Npn \tl_const:Nx #1#2 { \__chk_if_free_cs:N #1 \cs_gset_nopar:Npx #1 {#2} } \cs_generate_variant:Nn \tl_const:Nn { c } \cs_generate_variant:Nn \tl_const:Nx { c } % \end{macrocode} % \end{macro} % % \begin{macro}{\tl_clear:N, \tl_clear:c} % \begin{macro}{\tl_gclear:N, \tl_gclear:c} % Clearing a token list variable means setting it to an empty value. % Error checking will be sorted out by the parent function. % \begin{macrocode} \cs_new_protected:Npn \tl_clear:N #1 { \tl_set_eq:NN #1 \c_empty_tl } \cs_new_protected:Npn \tl_gclear:N #1 { \tl_gset_eq:NN #1 \c_empty_tl } \cs_generate_variant:Nn \tl_clear:N { c } \cs_generate_variant:Nn \tl_gclear:N { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_clear_new:N, \tl_clear_new:c} % \begin{macro}{\tl_gclear_new:N, \tl_gclear_new:c} % Clearing a token list variable means setting it to an empty value. % Error checking will be sorted out by the parent function. % \begin{macrocode} \cs_new_protected:Npn \tl_clear_new:N #1 { \tl_if_exist:NTF #1 { \tl_clear:N #1 } { \tl_new:N #1 } } \cs_new_protected:Npn \tl_gclear_new:N #1 { \tl_if_exist:NTF #1 { \tl_gclear:N #1 } { \tl_new:N #1 } } \cs_generate_variant:Nn \tl_clear_new:N { c } \cs_generate_variant:Nn \tl_gclear_new:N { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_set_eq:NN, \tl_set_eq:Nc, \tl_set_eq:cN, \tl_set_eq:cc} % \begin{macro}{\tl_gset_eq:NN, \tl_gset_eq:Nc, \tl_gset_eq:cN, \tl_gset_eq:cc} % For setting token list variables equal to each other. % \begin{macrocode} \cs_new_eq:NN \tl_set_eq:NN \cs_set_eq:NN \cs_new_eq:NN \tl_set_eq:cN \cs_set_eq:cN \cs_new_eq:NN \tl_set_eq:Nc \cs_set_eq:Nc \cs_new_eq:NN \tl_set_eq:cc \cs_set_eq:cc \cs_new_eq:NN \tl_gset_eq:NN \cs_gset_eq:NN \cs_new_eq:NN \tl_gset_eq:cN \cs_gset_eq:cN \cs_new_eq:NN \tl_gset_eq:Nc \cs_gset_eq:Nc \cs_new_eq:NN \tl_gset_eq:cc \cs_gset_eq:cc % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_concat:NNN, \tl_concat:ccc} % \begin{macro}{\tl_gconcat:NNN, \tl_gconcat:ccc} % Concatenating token lists is easy. % \begin{macrocode} \cs_new_protected:Npn \tl_concat:NNN #1#2#3 { \tl_set:Nx #1 { \exp_not:o {#2} \exp_not:o {#3} } } \cs_new_protected:Npn \tl_gconcat:NNN #1#2#3 { \tl_gset:Nx #1 { \exp_not:o {#2} \exp_not:o {#3} } } \cs_generate_variant:Nn \tl_concat:NNN { ccc } \cs_generate_variant:Nn \tl_gconcat:NNN { ccc } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}[pTF]{\tl_if_exist:N, \tl_if_exist:c} % Copies of the \texttt{cs} functions defined in \pkg{l3basics}. % \begin{macrocode} \cs_new_eq:NN \tl_if_exist:NTF \cs_if_exist:NTF \cs_new_eq:NN \tl_if_exist:NT \cs_if_exist:NT \cs_new_eq:NN \tl_if_exist:NF \cs_if_exist:NF \cs_new_eq:NN \tl_if_exist_p:N \cs_if_exist_p:N \cs_new_eq:NN \tl_if_exist:cTF \cs_if_exist:cTF \cs_new_eq:NN \tl_if_exist:cT \cs_if_exist:cT \cs_new_eq:NN \tl_if_exist:cF \cs_if_exist:cF \cs_new_eq:NN \tl_if_exist_p:c \cs_if_exist_p:c % \end{macrocode} % \end{macro} % % \subsection{Constant token lists} % % \begin{variable}{\c_empty_tl} % Never full. We need to define that constant before using \cs{tl_new:N}. % \begin{macrocode} \tl_const:Nn \c_empty_tl { } % \end{macrocode} % \end{variable} % % \begin{variable}{\c_job_name_tl} % Inherited from the \LaTeX3 name for the primitive: this needs to % actually contain the text of the job name rather than the name of % the primitive, of course. \LuaTeX{} does not quote file names containing % spaces, whereas \pdfTeX{} and \XeTeX{} do. So there may be a correction to % make in the \LuaTeX{} case. % \begin{macrocode} %<*initex> \luatex_if_engine:T { \tex_everyjob:D \exp_after:wN { \tex_the:D \tex_everyjob:D \lua_now_x:n { dofile ( assert ( kpse.find_file ("lualatexquotejobname.lua" ) ) ) } } } \tex_everyjob:D \exp_after:wN { \tex_the:D \tex_everyjob:D \tl_const:Nx \c_job_name_tl { \tex_jobname:D } } % %<*package> \tl_const:Nx \c_job_name_tl { \tex_jobname:D } % % \end{macrocode} % \end{variable} % % \begin{variable}{\c_space_tl} % A space as a token list (as opposed to as a character). % \begin{macrocode} \tl_const:Nn \c_space_tl { ~ } % \end{macrocode} % \end{variable} % % \subsection{Adding to token list variables} % % \begin{macro} % { % \tl_set:Nn, \tl_set:NV, \tl_set:Nv, \tl_set:No, \tl_set:Nf, \tl_set:Nx, % \tl_set:cn, \tl_set:cV, \tl_set:cv, \tl_set:co, \tl_set:cf, \tl_set:cx % } % \begin{macro} % { % \tl_gset:Nn, \tl_gset:NV, \tl_gset:Nv, % \tl_gset:No, \tl_gset:Nf, \tl_gset:Nx, % \tl_gset:cn, \tl_gset:cV, \tl_gset:cv, % \tl_gset:co, \tl_gset:cf, \tl_gset:cx % } % By using \cs{exp_not:n} token list variables can contain |#| tokens, % which makes the token list registers provided by \TeX{} % more or less redundant. The \cs{tl_set:No} version is done % \enquote{by hand} as it is used quite a lot. % \begin{macrocode} \cs_new_protected:Npn \tl_set:Nn #1#2 { \cs_set_nopar:Npx #1 { \exp_not:n {#2} } } \cs_new_protected:Npn \tl_set:No #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o {#2} } } \cs_new_protected:Npn \tl_set:Nx #1#2 { \cs_set_nopar:Npx #1 {#2} } \cs_new_protected:Npn \tl_gset:Nn #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:n {#2} } } \cs_new_protected:Npn \tl_gset:No #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o {#2} } } \cs_new_protected:Npn \tl_gset:Nx #1#2 { \cs_gset_nopar:Npx #1 {#2} } \cs_generate_variant:Nn \tl_set:Nn { NV , Nv , Nf } \cs_generate_variant:Nn \tl_set:Nx { c } \cs_generate_variant:Nn \tl_set:Nn { c, co , cV , cv , cf } \cs_generate_variant:Nn \tl_gset:Nn { NV , Nv , Nf } \cs_generate_variant:Nn \tl_gset:Nx { c } \cs_generate_variant:Nn \tl_gset:Nn { c, co , cV , cv , cf } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro} % { % \tl_put_left:Nn, \tl_put_left:NV, \tl_put_left:No, \tl_put_left:Nx, % \tl_put_left:cn, \tl_put_left:cV, \tl_put_left:co, \tl_put_left:cx % } % \begin{macro} % { % \tl_gput_left:Nn, \tl_gput_left:NV, \tl_gput_left:No, \tl_gput_left:Nx, % \tl_gput_left:cn, \tl_gput_left:cV, \tl_gput_left:co, \tl_gput_left:cx % } % Adding to the left is done directly to gain a little performance. % \begin{macrocode} \cs_new_protected:Npn \tl_put_left:Nn #1#2 { \cs_set_nopar:Npx #1 { \exp_not:n {#2} \exp_not:o #1 } } \cs_new_protected:Npn \tl_put_left:NV #1#2 { \cs_set_nopar:Npx #1 { \exp_not:V #2 \exp_not:o #1 } } \cs_new_protected:Npn \tl_put_left:No #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o {#2} \exp_not:o #1 } } \cs_new_protected:Npn \tl_put_left:Nx #1#2 { \cs_set_nopar:Npx #1 { #2 \exp_not:o #1 } } \cs_new_protected:Npn \tl_gput_left:Nn #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:n {#2} \exp_not:o #1 } } \cs_new_protected:Npn \tl_gput_left:NV #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:V #2 \exp_not:o #1 } } \cs_new_protected:Npn \tl_gput_left:No #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o {#2} \exp_not:o #1 } } \cs_new_protected:Npn \tl_gput_left:Nx #1#2 { \cs_gset_nopar:Npx #1 { #2 \exp_not:o {#1} } } \cs_generate_variant:Nn \tl_put_left:Nn { c } \cs_generate_variant:Nn \tl_put_left:NV { c } \cs_generate_variant:Nn \tl_put_left:No { c } \cs_generate_variant:Nn \tl_put_left:Nx { c } \cs_generate_variant:Nn \tl_gput_left:Nn { c } \cs_generate_variant:Nn \tl_gput_left:NV { c } \cs_generate_variant:Nn \tl_gput_left:No { c } \cs_generate_variant:Nn \tl_gput_left:Nx { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro} % { % \tl_put_right:Nn, \tl_put_right:NV, \tl_put_right:No, \tl_put_right:Nx, % \tl_put_right:cn, \tl_put_right:cV, \tl_put_right:co, \tl_put_right:cx % } % \begin{macro} % { % \tl_gput_right:Nn, \tl_gput_right:NV, \tl_gput_right:No, % \tl_gput_right:Nx, % \tl_gput_right:cn, \tl_gput_right:cV, \tl_gput_right:co, % \tl_gput_right:cx % } % The same on the right. % \begin{macrocode} \cs_new_protected:Npn \tl_put_right:Nn #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o #1 \exp_not:n {#2} } } \cs_new_protected:Npn \tl_put_right:NV #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o #1 \exp_not:V #2 } } \cs_new_protected:Npn \tl_put_right:No #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o #1 \exp_not:o {#2} } } \cs_new_protected:Npn \tl_put_right:Nx #1#2 { \cs_set_nopar:Npx #1 { \exp_not:o #1 #2 } } \cs_new_protected:Npn \tl_gput_right:Nn #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o #1 \exp_not:n {#2} } } \cs_new_protected:Npn \tl_gput_right:NV #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o #1 \exp_not:V #2 } } \cs_new_protected:Npn \tl_gput_right:No #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o #1 \exp_not:o {#2} } } \cs_new_protected:Npn \tl_gput_right:Nx #1#2 { \cs_gset_nopar:Npx #1 { \exp_not:o {#1} #2 } } \cs_generate_variant:Nn \tl_put_right:Nn { c } \cs_generate_variant:Nn \tl_put_right:NV { c } \cs_generate_variant:Nn \tl_put_right:No { c } \cs_generate_variant:Nn \tl_put_right:Nx { c } \cs_generate_variant:Nn \tl_gput_right:Nn { c } \cs_generate_variant:Nn \tl_gput_right:NV { c } \cs_generate_variant:Nn \tl_gput_right:No { c } \cs_generate_variant:Nn \tl_gput_right:Nx { c } % \end{macrocode} % \end{macro} % \end{macro} % % \subsection{Reassigning token list category codes} % % \begin{variable}{\c_@@_rescan_marker_tl} % The rescanning code needs a special token list containing the same % character with two different category codes. This is set up here, % while the detail is described below. % \begin{macrocode} \group_begin: \tex_lccode:D `\A = `\@ \scan_stop: \tex_lccode:D `\B = `\@ \scan_stop: \tex_catcode:D `\A = 8 \scan_stop: \tex_catcode:D `\B = 3 \scan_stop: \tex_lowercase:D { \group_end: \tl_const:Nn \c_@@_rescan_marker_tl { A B } } % \end{macrocode} % \end{variable} % % \begin{macro} % { % \tl_set_rescan:Nnn, \tl_set_rescan:Nno, \tl_set_rescan:Nnx, % \tl_set_rescan:cnn, \tl_set_rescan:cno, \tl_set_rescan:cnx % } % \begin{macro} % { % \tl_gset_rescan:Nnn, \tl_gset_rescan:Nno, \tl_gset_rescan:Nnx, % \tl_gset_rescan:cnn, \tl_gset_rescan:cno, \tl_gset_rescan:cnx % } % \begin{macro}{\tl_rescan:nn} % \begin{macro}[aux]{\@@_set_rescan:NNnn} % \begin{macro}[aux]{\@@_rescan:w} % The idea here is to deal cleanly with the problem that % \tn{scantokens} treats the argument as a file, and without % the correct settings a \TeX{} error occurs: % \begin{verbatim} % ! File ended while scanning definition of ... % \end{verbatim} % When expanding a token list this can be handled using \cs{exp_not:N} % but this fails if the token list is not being expanded. So instead % a delimited argument is used with an end marker which cannot appear % within the token list which is scanned: two |@| symbols with different % category codes. The rescanned token list cannot contain the end marker, % because all |@| present in the token list are read with the same category % code. As every character with charcode \tn{newlinechar} is replaced % by the \tn{endlinechar}, and an extra \tn{endlinechar} is % added at the end, we need to set both of those to $-1$, % \enquote{unprintable}. % \begin{macrocode} \cs_new_protected_nopar:Npn \tl_set_rescan:Nnn { \@@_set_rescan:NNnn \tl_set:Nn } \cs_new_protected_nopar:Npn \tl_gset_rescan:Nnn { \@@_set_rescan:NNnn \tl_gset:Nn } \cs_new_protected_nopar:Npn \tl_rescan:nn { \@@_set_rescan:NNnn \prg_do_nothing: \use:n } \cs_new_protected:Npn \@@_set_rescan:NNnn #1#2#3#4 { \group_begin: \exp_args:No \etex_everyeof:D { \c_@@_rescan_marker_tl \exp_not:N } \tex_endlinechar:D \c_minus_one \tex_newlinechar:D \c_minus_one #3 \use:x { \group_end: #1 \exp_not:N #2 { \exp_after:wN \@@_rescan:w \exp_after:wN \prg_do_nothing: \etex_scantokens:D {#4} } } } \use:x { \cs_new:Npn \exp_not:N \@@_rescan:w ##1 \c_@@_rescan_marker_tl { \exp_not:N \exp_not:o { ##1 } } } \cs_generate_variant:Nn \tl_set_rescan:Nnn { Nno , Nnx } \cs_generate_variant:Nn \tl_set_rescan:Nnn { c , cno , cnx } \cs_generate_variant:Nn \tl_gset_rescan:Nnn { Nno , Nnx } \cs_generate_variant:Nn \tl_gset_rescan:Nnn { c , cno } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \subsection{Reassigning token list character codes} % % \begin{macro}{\tl_to_lowercase:n} % \begin{macro}{\tl_to_uppercase:n} % Just some names for a few primitives: we take care or wrapping the % argument in braces. % \begin{macrocode} \cs_new_protected:Npn \tl_to_lowercase:n #1 { \tex_lowercase:D {#1} } \cs_new_protected:Npn \tl_to_uppercase:n #1 { \tex_uppercase:D {#1} } % \end{macrocode} % \end{macro} % \end{macro} % % \subsection{Modifying token list variables} % % \begin{macro}{\tl_replace_all:Nnn, \tl_replace_all:cnn} % \begin{macro}{\tl_greplace_all:Nnn, \tl_greplace_all:cnn} % \begin{macro}{\tl_replace_once:Nnn, \tl_replace_once:cnn} % \begin{macro}{\tl_greplace_once:Nnn, \tl_greplace_once:cnn} % \begin{macro}[aux]{\@@_replace:NNNnn, \@@_replace:w} % \begin{macro}[aux]{\@@_replace_all:, \@@_replace_once:} % \begin{macro}[aux]{\@@_replace_once_end:w} % All of the replace functions are based on \cs{@@_replace:NNNnn}, % whose arguments are: \meta{function}, \cs{tl_(g)set:Nx}, \meta{tl~var}, % \meta{search tokens}, \meta{replacement tokens}. % \begin{macrocode} \cs_new_protected_nopar:Npn \tl_replace_once:Nnn { \@@_replace:NNNnn \@@_replace_once: \tl_set:Nx } \cs_new_protected_nopar:Npn \tl_greplace_once:Nnn { \@@_replace:NNNnn \@@_replace_once: \tl_gset:Nx } \cs_new_protected_nopar:Npn \tl_replace_all:Nnn { \@@_replace:NNNnn \@@_replace_all: \tl_set:Nx } \cs_new_protected_nopar:Npn \tl_greplace_all:Nnn { \@@_replace:NNNnn \@@_replace_all: \tl_gset:Nx } \cs_generate_variant:Nn \tl_replace_once:Nnn { c } \cs_generate_variant:Nn \tl_greplace_once:Nnn { c } \cs_generate_variant:Nn \tl_replace_all:Nnn { c } \cs_generate_variant:Nn \tl_greplace_all:Nnn { c } % \end{macrocode} % The idea is easier to understand by considering the case of % \cs{tl_replace_all:Nnn}. The replacement happens within an % \texttt{x}-type expansion. We use an auxiliary function \cs{@@_tmp:w}, % which essentially replaces the next \meta{search tokens} by % \meta{replacement tokens}. To avoid runaway arguments, % we expand something like \cs{@@_tmp:w} \meta{token list} \cs{q_mark} % \meta{search tokens} \cs{q_stop}, repeating until the end. How do we % detect that we have reached the last occurrence of \meta{search tokens}? % The last replacement is characterized by the fact that the argument of % \cs{@@_tmp:w} contains \cs{q_mark}. In the code below, % \cs{@@_replace:w} takes an argument delimited by \cs{q_mark}, % and removes the following token. Before we reach the end, this gobbles % \cs{q_mark} \cs{use_none_delimit_by_q_stop:w} which appear in the % definition of \cs{@@_tmp:w}, and leaves the \meta{replacement tokens}, % passed to \cs{exp_not:n}, to be included in the \texttt{x}-expanding % definition. At the end, the first \cs{q_mark} is within the argument % of \cs{@@_tmp:w}, and \cs{@@_replace:w} gobbles the second % \cs{q_mark} as well, leaving \cs{use_none_delimit_by_q_stop:w}, % which ends the recursion cleanly. % \begin{macrocode} \cs_new_protected:Npn \@@_replace:NNNnn #1#2#3#4#5 { \tl_if_empty:nTF {#4} { \__msg_kernel_error:nnx { kernel } { empty-search-pattern } { \tl_to_str:n {#5} } } { \group_align_safe_begin: \cs_set:Npx \@@_tmp:w ##1##2 #4 { ##2 \exp_not:N \q_mark \exp_not:N \use_none_delimit_by_q_stop:w \exp_not:n { \exp_not:n {#5} } ##1 } \group_align_safe_end: #2 #3 { \exp_after:wN #1 #3 \q_mark #4 \q_stop } } } \cs_new:Npn \@@_replace:w #1 \q_mark #2 { \exp_not:o {#1} } % \end{macrocode} % The first argument of \cs{@@_tmp:w} is responsible for repeating % the replacement in the case of \texttt{replace_all}, and stopping % it early for \texttt{replace_once}. Note also that we build % \cs{@@_tmp:w} within an \texttt{x}-expansion so that the % \meta{replacement tokens} can contain |#|. The second % \cs{exp_not:n} ensures that the \meta{replacement tokens} % are not expanded by \cs{tl_(g)set:Nx}. % % Now on to the difference between \enquote{once} and \enquote{all}. % The \cs{prg_do_nothing:} and accompanying \texttt{o}-expansion % ensure that we don't lose braces in case the tokens between two % occurrences of the \meta{search tokens} form a brace group. % \begin{macrocode} \cs_new_nopar:Npn \@@_replace_all: { \exp_after:wN \@@_replace:w \@@_tmp:w \@@_replace_all: \prg_do_nothing: } \cs_new_nopar:Npn \@@_replace_once: { \exp_after:wN \@@_replace:w \@@_tmp:w { \@@_replace_once_end:w \prg_do_nothing: } \prg_do_nothing: } \cs_new:Npn \@@_replace_once_end:w #1 \q_mark #2 \q_stop { \exp_not:o {#1} } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_remove_once:Nn, \tl_remove_once:cn} % \begin{macro}{\tl_gremove_once:Nn, \tl_gremove_once:cn} % Removal is just a special case of replacement. % \begin{macrocode} \cs_new_protected:Npn \tl_remove_once:Nn #1#2 { \tl_replace_once:Nnn #1 {#2} { } } \cs_new_protected:Npn \tl_gremove_once:Nn #1#2 { \tl_greplace_once:Nnn #1 {#2} { } } \cs_generate_variant:Nn \tl_remove_once:Nn { c } \cs_generate_variant:Nn \tl_gremove_once:Nn { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_remove_all:Nn, \tl_remove_all:cn} % \begin{macro}{\tl_gremove_all:Nn, \tl_gremove_all:cn} % Removal is just a special case of replacement. % \begin{macrocode} \cs_new_protected:Npn \tl_remove_all:Nn #1#2 { \tl_replace_all:Nnn #1 {#2} { } } \cs_new_protected:Npn \tl_gremove_all:Nn #1#2 { \tl_greplace_all:Nnn #1 {#2} { } } \cs_generate_variant:Nn \tl_remove_all:Nn { c } \cs_generate_variant:Nn \tl_gremove_all:Nn { c } % \end{macrocode} % \end{macro} % % \subsection{Token list conditionals} % % \begin{macro}[pTF]{\tl_if_blank:n,\tl_if_blank:V,\tl_if_blank:o} % \begin{macro}[aux]{\@@_if_blank_p:NNw} % \TeX{} skips spaces when reading a non-delimited arguments. Thus, % a \meta{token list} is blank if and only if \cs{use_none:n} % \meta{token list} |?| is empty. For performance reasons, we hard-code % the emptyness test done in \cs{tl_if_empty:n(TF)}: convert to harmless % characters with \cs{tl_to_str:n}, and then use % \cs{if_meaning:w} \cs{q_nil} |...| \cs{q_nil}. % Note that converting to a string is done after reading the delimited % argument for \cs{use_none:n}. The similar construction % \cs{exp_after:wN} \cs{use_none:n} \cs{tl_to_str:n} \Arg{token list} |?| % would fail if the token list contains the control sequence \cs{ }, % while \tn{escapechar} is a space or is unprintable. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_blank:n #1 { p , T , F , TF } { \@@_if_empty_return:o { \use_none:n #1 ? } } \cs_generate_variant:Nn \tl_if_blank_p:n { V } \cs_generate_variant:Nn \tl_if_blank:nT { V } \cs_generate_variant:Nn \tl_if_blank:nF { V } \cs_generate_variant:Nn \tl_if_blank:nTF { V } \cs_generate_variant:Nn \tl_if_blank_p:n { o } \cs_generate_variant:Nn \tl_if_blank:nT { o } \cs_generate_variant:Nn \tl_if_blank:nF { o } \cs_generate_variant:Nn \tl_if_blank:nTF { o } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}[pTF]{\tl_if_empty:N,\tl_if_empty:c} % These functions check whether the token list in the argument is % empty and execute the proper code from their argument(s). % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_empty:N #1 { p , T , F , TF } { \if_meaning:w #1 \c_empty_tl \prg_return_true: \else: \prg_return_false: \fi: } \cs_generate_variant:Nn \tl_if_empty_p:N { c } \cs_generate_variant:Nn \tl_if_empty:NT { c } \cs_generate_variant:Nn \tl_if_empty:NF { c } \cs_generate_variant:Nn \tl_if_empty:NTF { c } % \end{macrocode} % \end{macro} % % \begin{macro}[pTF]{\tl_if_empty:n,\tl_if_empty:V} % It would be tempting to just use |\if_meaning:w \q_nil #1 \q_nil| as % a test since this works really well. However, it fails on a token % list starting with \cs{q_nil} of course but more troubling is the % case where argument is a complete conditional such as \cs{if_true:} % a \cs{else:} b \cs{fi:} because then \cs{if_true:} is used by % \cs{if_meaning:w}, the test turns out \texttt{false}, the \cs{else:} % executes the \texttt{false} branch, the \cs{fi:} ends it and the % \cs{q_nil} at the end % starts executing\dots{} A safer route is to convert the entire % token list into harmless characters first and then compare % that. This way the test will even accept \cs{q_nil} as the first % token. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_empty:n #1 { p , TF , T , F } { \exp_after:wN \if_meaning:w \exp_after:wN \q_nil \tl_to_str:n {#1} \q_nil \prg_return_true: \else: \prg_return_false: \fi: } \cs_generate_variant:Nn \tl_if_empty_p:n { V } \cs_generate_variant:Nn \tl_if_empty:nTF { V } \cs_generate_variant:Nn \tl_if_empty:nT { V } \cs_generate_variant:Nn \tl_if_empty:nF { V } % \end{macrocode} % \end{macro} % % \begin{macro}[pTF]{\tl_if_empty:o} % \begin{macro}[EXP,aux]{\@@_if_empty_return:o} % The auxiliary function \cs{@@_if_empty_return:o} is for use % in conditionals on token lists, which mostly reduce to testing % if a given token list is empty after applying a simple function % to it. % The test for emptiness is based on \cs{tl_if_empty:n(TF)}, but % the expansion is hard-coded for efficiency, as this auxiliary % function is used in many places. % Note that this works because \cs{tl_to_str:n} expands tokens % that follow until reading a catcode $1$ (begin-group) token. % \begin{macrocode} \cs_new:Npn \@@_if_empty_return:o #1 { \exp_after:wN \if_meaning:w \exp_after:wN \q_nil \tl_to_str:n \exp_after:wN {#1} \q_nil \prg_return_true: \else: \prg_return_false: \fi: } \prg_new_conditional:Npnn \tl_if_empty:o #1 { p , TF , T , F } { \@@_if_empty_return:o {#1} } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}[pTF]{\tl_if_eq:NN, \tl_if_eq:Nc, \tl_if_eq:cN, \tl_if_eq:cc} % Returns \cs{c_true_bool} if and only if the two token list variables are % equal. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_eq:NN #1#2 { p , T , F , TF } { \if_meaning:w #1 #2 \prg_return_true: \else: \prg_return_false: \fi: } \cs_generate_variant:Nn \tl_if_eq_p:NN { Nc , c , cc } \cs_generate_variant:Nn \tl_if_eq:NNTF { Nc , c , cc } \cs_generate_variant:Nn \tl_if_eq:NNT { Nc , c , cc } \cs_generate_variant:Nn \tl_if_eq:NNF { Nc , c , cc } % \end{macrocode} % \end{macro} % % \begin{macro}[TF]{\tl_if_eq:nn} % \begin{variable}{\l_@@_internal_a_tl, \l_@@_internal_b_tl} % A simple store and compare routine. % \begin{macrocode} \prg_new_protected_conditional:Npnn \tl_if_eq:nn #1#2 { T , F , TF } { \group_begin: \tl_set:Nn \l_@@_internal_a_tl {#1} \tl_set:Nn \l_@@_internal_b_tl {#2} \if_meaning:w \l_@@_internal_a_tl \l_@@_internal_b_tl \group_end: \prg_return_true: \else: \group_end: \prg_return_false: \fi: } \tl_new:N \l_@@_internal_a_tl \tl_new:N \l_@@_internal_b_tl % \end{macrocode} % \end{variable} % \end{macro} % % \begin{macro}[TF]{\tl_if_in:Nn, \tl_if_in:cn} % See \cs{tl_if_in:nn(TF)} for further comments. Here we simply % expand the token list variable and pass it to \cs{tl_if_in:nn(TF)}. % \begin{macrocode} \cs_new_protected_nopar:Npn \tl_if_in:NnT { \exp_args:No \tl_if_in:nnT } \cs_new_protected_nopar:Npn \tl_if_in:NnF { \exp_args:No \tl_if_in:nnF } \cs_new_protected_nopar:Npn \tl_if_in:NnTF { \exp_args:No \tl_if_in:nnTF } \cs_generate_variant:Nn \tl_if_in:NnT { c } \cs_generate_variant:Nn \tl_if_in:NnF { c } \cs_generate_variant:Nn \tl_if_in:NnTF { c } % \end{macrocode} % \end{macro} % % \begin{macro}[TF]{\tl_if_in:nn, \tl_if_in:Vn, \tl_if_in:on, \tl_if_in:no} % Once more, the test relies on \cs{tl_to_str:n} for robustness. % The function \cs{@@_tmp:w} removes tokens until the first occurrence % of |#2|. If this does not appear in |#1|, then the final |#2| is removed, % leaving an empty token list. Otherwise some tokens remain, and the % test is \texttt{false}. See \cs{tl_if_empty:n(TF)} for details on % the emptyness test. % % Special care is needed to treat correctly cases like % |\tl_if_in:nnTF {a state}{states}|, where |#1#2| contains |#2| before % the end. To cater for this case, we insert |{}{}| between the two token % lists. This marker may not appear in |#2| because of \TeX{} limitations % on what can delimit a parameter, hence we are safe. Using two brace % groups makes the test work also for empty arguments. % \begin{macrocode} \prg_new_protected_conditional:Npnn \tl_if_in:nn #1#2 { T , F , TF } { \cs_set:Npn \@@_tmp:w ##1 #2 { } \tl_if_empty:oTF { \@@_tmp:w #1 {} {} #2 } { \prg_return_false: } { \prg_return_true: } } \cs_generate_variant:Nn \tl_if_in:nnT { V , o , no } \cs_generate_variant:Nn \tl_if_in:nnF { V , o , no } \cs_generate_variant:Nn \tl_if_in:nnTF { V , o , no } % \end{macrocode} % \end{macro} % % \begin{macro}[EXP,pTF]{\tl_if_single:N} % Expand the token list and feed it to \cs{tl_if_single:n}. % \begin{macrocode} \cs_new:Npn \tl_if_single_p:N { \exp_args:No \tl_if_single_p:n } \cs_new:Npn \tl_if_single:NT { \exp_args:No \tl_if_single:nT } \cs_new:Npn \tl_if_single:NF { \exp_args:No \tl_if_single:nF } \cs_new:Npn \tl_if_single:NTF { \exp_args:No \tl_if_single:nTF } % \end{macrocode} % \end{macro} % % \begin{macro}[EXP,pTF]{\tl_if_single:n} % A token list has exactly one item if it is a single token or a % single brace group, surrounded by optional explicit spaces. % The naive % version of this test would do \cs{use_none:n} |#1|, and % test if the result is empty. However, this will fail when % the token list is empty. Furthermore, it does not allow optional % trailing spaces. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_single:n #1 { p , T , F , TF } { \__str_if_eq_x_return:nn { \exp_not:o { \use_none:nn #1 ?? } } {?} } % \end{macrocode} % \end{macro} % % \begin{macro}[EXP]{\tl_case:Nnn, \tl_case:cnn} % \begin{macro}[aux, EXP]{\@@_case:Nw} % \begin{macro}[aux, EXP]{\@@_case_end:nw} % \begin{macrocode} \cs_new:Npn \tl_case:Nnn #1#2#3 { \tex_romannumeral:D \@@_case:Nw #1 #2 #1 {#3} \q_recursion_stop } \cs_new:Npn \@@_case:Nw #1#2#3 { \tl_if_eq:NNTF #1 #2 { \@@_case_end:nw {#3} } { \@@_case:Nw #1 } } \cs_generate_variant:Nn \tl_case:Nnn { c } \cs_new_eq:NN \@@_case_end:nw \__prg_case_end:nw % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \subsection{Mapping to token lists} % % \begin{macro}{\tl_map_function:nN} % \begin{macro}{\tl_map_function:NN, \tl_map_function:cN} % \begin{macro}[aux]{\@@_map_function:Nn} % Expandable loop macro for token lists. These have the advantage of not % needing to test if the argument is empty, because if it is, the stop % marker will be read immediately and the loop terminated. % \begin{macrocode} \cs_new:Npn \tl_map_function:nN #1#2 { \@@_map_function:Nn #2 #1 \q_recursion_tail \__prg_break_point:Nn \tl_map_break: { } } \cs_new_nopar:Npn \tl_map_function:NN { \exp_args:No \tl_map_function:nN } \cs_new:Npn \@@_map_function:Nn #1#2 { \__quark_if_recursion_tail_break:nN {#2} \tl_map_break: #1 {#2} \@@_map_function:Nn #1 } \cs_generate_variant:Nn \tl_map_function:NN { c } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_map_inline:nn} % \begin{macro}{\tl_map_inline:Nn, \tl_map_inline:cn} % The inline functions are straight forward by now. We use a little % trick with the counter \cs{g__prg_map_int} to make % them nestable. We can also make use of \cs{@@_map_function:Nn} % from before. % \begin{macrocode} \cs_new_protected:Npn \tl_map_inline:nn #1#2 { \int_gincr:N \g__prg_map_int \cs_gset:cpn { __prg_map_ \int_use:N \g__prg_map_int :w } ##1 {#2} \exp_args:Nc \@@_map_function:Nn { __prg_map_ \int_use:N \g__prg_map_int :w } #1 \q_recursion_tail \__prg_break_point:Nn \tl_map_break: { \int_gdecr:N \g__prg_map_int } } \cs_new_protected:Npn \tl_map_inline:Nn { \exp_args:No \tl_map_inline:nn } \cs_generate_variant:Nn \tl_map_inline:Nn { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_map_variable:nNn} % \begin{macro}{\tl_map_variable:NNn, \tl_map_variable:cNn} % \begin{macro}[aux]{\@@_map_variable:Nnn} % \cs{tl_map_variable:nNn} \meta{token list} \meta{temp} \meta{action} % assigns % \meta{temp} to each element and executes \meta{action}. % \begin{macrocode} \cs_new_protected:Npn \tl_map_variable:nNn #1#2#3 { \@@_map_variable:Nnn #2 {#3} #1 \q_recursion_tail \__prg_break_point:Nn \tl_map_break: { } } \cs_new_protected_nopar:Npn \tl_map_variable:NNn { \exp_args:No \tl_map_variable:nNn } \cs_new_protected:Npn \@@_map_variable:Nnn #1#2#3 { \tl_set:Nn #1 {#3} \__quark_if_recursion_tail_break:NN #1 \tl_map_break: \use:n {#2} \@@_map_variable:Nnn #1 {#2} } \cs_generate_variant:Nn \tl_map_variable:NNn { c } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_map_break:} % \begin{macro}{\tl_map_break:n} % The break statements use the general \cs{__prg_map_break:Nn}. % \begin{macrocode} \cs_new_nopar:Npn \tl_map_break: { \__prg_map_break:Nn \tl_map_break: { } } \cs_new_nopar:Npn \tl_map_break:n { \__prg_map_break:Nn \tl_map_break: } % \end{macrocode} % \end{macro} % \end{macro} % % \subsection{Using token lists} % % \begin{macro}{\tl_to_str:n} % Another name for a primitive. % \begin{macrocode} \cs_new_eq:NN \tl_to_str:n \etex_detokenize:D % \end{macrocode} % \end{macro} % % \begin{macro}{\tl_to_str:N, \tl_to_str:c} % These functions return the replacement text of a token list as a % string. % \begin{macrocode} \cs_new:Npn \tl_to_str:N #1 { \etex_detokenize:D \exp_after:wN {#1} } \cs_generate_variant:Nn \tl_to_str:N { c } % \end{macrocode} % \end{macro} % % \begin{macro}{\tl_use:N, \tl_use:c} % Token lists which are simply not defined will give a clear \TeX{} % error here. No such luck for ones equal to \cs{scan_stop:} so % instead a test is made and if there is an issue an error is forced. % \begin{macrocode} \cs_new:Npn \tl_use:N #1 { \tl_if_exist:NTF #1 {#1} { \__msg_kernel_expandable_error:nnn { kernel } { bad-variable } {#1} } } \cs_generate_variant:Nn \tl_use:N { c } % \end{macrocode} % \end{macro} % % \subsection{Working with the contents of token lists} % % \begin{macro}{\tl_count:n, \tl_count:V, \tl_count:o} % \begin{macro}{\tl_count:N, \tl_count:c} % \begin{macro}[aux]{\@@_count:n} % Count number of elements within a token list or token list % variable. Brace groups within the list are read as a single % element. Spaces are ignored. % \cs{@@_count:n} grabs the element and replaces it by |+1|. % The |0| to ensure it works on an empty list. % \begin{macrocode} \cs_new:Npn \tl_count:n #1 { \int_eval:n { 0 \tl_map_function:nN {#1} \@@_count:n } } \cs_new:Npn \tl_count:N #1 { \int_eval:n { 0 \tl_map_function:NN #1 \@@_count:n } } \cs_new:Npn \@@_count:n #1 { + \c_one } \cs_generate_variant:Nn \tl_count:n { V , o } \cs_generate_variant:Nn \tl_count:N { c } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_reverse_items:n} % \begin{macro}[aux]{\@@_reverse_items:nwNwn} % \begin{macro}[aux]{\@@_reverse_items:wn} % Reversal of a token list is done by taking one item at a time % and putting it after \cs{q_stop}. % \begin{macrocode} \cs_new:Npn \tl_reverse_items:n #1 { \@@_reverse_items:nwNwn #1 ? \q_mark \@@_reverse_items:nwNwn \q_mark \@@_reverse_items:wn \q_stop { } } \cs_new:Npn \@@_reverse_items:nwNwn #1 #2 \q_mark #3 #4 \q_stop #5 { #3 #2 \q_mark \@@_reverse_items:nwNwn \q_mark \@@_reverse_items:wn \q_stop { {#1} #5 } } \cs_new:Npn \@@_reverse_items:wn #1 \q_stop #2 { \exp_not:o { \use_none:nn #2 } } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_trim_spaces:n} % \begin{macro} % { % \tl_trim_spaces:N, \tl_trim_spaces:c, % \tl_gtrim_spaces:N, \tl_gtrim_spaces:c % } % Trimming spaces from around the input is deferred to an internal % function whose first argument is the token list to trim, augmented % by an initial \cs{q_mark}, and whose second argument is a % \meta{continuation}, which will receive as a braced argument % \cs{use_none:n} \cs{q_mark} \meta{trimmed token list}. In the case % at hand, we take \cs{exp_not:o} as our continuation, so that space % trimming will behave correctly within an \texttt{x}-type expansion. % \begin{macrocode} \cs_new:Npn \tl_trim_spaces:n #1 { \@@_trim_spaces:nn { \q_mark #1 } \exp_not:o } \cs_new_protected:Npn \tl_trim_spaces:N #1 { \tl_set:Nx #1 { \exp_args:No \tl_trim_spaces:n {#1} } } \cs_new_protected:Npn \tl_gtrim_spaces:N #1 { \tl_gset:Nx #1 { \exp_args:No \tl_trim_spaces:n {#1} } } \cs_generate_variant:Nn \tl_trim_spaces:N { c } \cs_generate_variant:Nn \tl_gtrim_spaces:N { c } % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}[int]{\@@_trim_spaces:nn} % \begin{macro}[aux] % { % \@@_trim_spaces_auxi:w, \@@_trim_spaces_auxii:w % \@@_trim_spaces_auxiii:w, \@@_trim_spaces_auxiv:w % } % Trimming spaces from around the input is done using delimited % arguments and quarks, and to get spaces at odd places in the % definitions, we nest those in \cs{@@_tmp:w}, which then receives % a single space as its argument: |#1| is \verb*+ +. % Removing leading spaces is done with \cs{@@_trim_spaces_auxi:w}, % which loops until \cs{q_mark}\verb*+ + matches the end of the token % list: then |##1| is the token list and |##3| is % \cs{@@_trim_spaces_auxii:w}. This hands the relevant tokens to the % loop \cs{@@_trim_spaces_auxiii:w}, responsible for trimming % trailing spaces. The end is reached when \verb*+ + \cs{q_nil} % matches the one present in the definition of \cs{tl_trim_spacs:n}. % Then \cs{@@_trim_spaces_auxiv:w} puts the token list into a group, % with \cs{use_none:n} placed there to gobble a lingering \cs{q_mark}, % and feeds this to the \meta{continuation}. % \begin{macrocode} \cs_set:Npn \@@_tmp:w #1 { \cs_new:Npn \@@_trim_spaces:nn ##1 { \@@_trim_spaces_auxi:w ##1 \q_nil \q_mark #1 { } \q_mark \@@_trim_spaces_auxii:w \@@_trim_spaces_auxiii:w #1 \q_nil \@@_trim_spaces_auxiv:w \q_stop } \cs_new:Npn \@@_trim_spaces_auxi:w ##1 \q_mark #1 ##2 \q_mark ##3 { ##3 \@@_trim_spaces_auxi:w \q_mark ##2 \q_mark #1 {##1} } \cs_new:Npn \@@_trim_spaces_auxii:w \@@_trim_spaces_auxi:w \q_mark \q_mark ##1 { \@@_trim_spaces_auxiii:w ##1 } \cs_new:Npn \@@_trim_spaces_auxiii:w ##1 #1 \q_nil ##2 { ##2 ##1 \q_nil \@@_trim_spaces_auxiii:w } \cs_new:Npn \@@_trim_spaces_auxiv:w ##1 \q_nil ##2 \q_stop ##3 { ##3 { \use_none:n ##1 } } } \@@_tmp:w { ~ } % \end{macrocode} % \end{macro} % \end{macro} % % \subsection{Token by token changes} % % \begin{variable}{\q__@@_act_mark,\q__@@_act_stop} % The \cs{tl_act} functions may be applied to any token list. % Hence, we use two private quarks, to allow any token, even quarks, % in the token list.^^A in particular critical for future \::e. % Only \cs{q__@@_act_mark} and \cs{q__@@_act_stop} may not appear % in the token lists manipulated by \cs{@@_act:NNNnn} functions. The quarks % are effectively defined in \pkg{l3quark}. % \end{variable} % % \begin{macro}[EXP,int]{\@@_act:NNNnn} % \begin{macro}[EXP,aux]{\@@_act_output:n, \@@_act_reverse_output:n} % \begin{macro}[EXP,aux]{\@@_act_loop:w} % \begin{macro}[EXP,aux]{\@@_act_normal:NwnNNN} % \begin{macro}[EXP,aux]{\@@_act_group:nwnNNN} % \begin{macro}[EXP,aux]{\@@_act_space:wwnNNN} % \begin{macro}[EXP,aux]{\@@_act_end:w} % To help control the expansion, \cs{@@_act:NNNnn} should always % be proceeded by \tn{romannumeral} and ends by producing \cs{c_zero} % once the result has been obtained. Then loop over tokens, % groups, and spaces in |#5|. The marker \cs{q__@@_act_mark} % is used both to avoid losing outer braces and to detect the % end of the token list more easily. The result is stored % as an argument for the dummy function \cs{@@_act_result:n}. % \begin{macrocode} \cs_new:Npn \@@_act:NNNnn #1#2#3#4#5 { \group_align_safe_begin: \@@_act_loop:w #5 \q__@@_act_mark \q__@@_act_stop {#4} #1 #2 #3 \@@_act_result:n { } } % \end{macrocode} % In the loop, we check how the token list begins and act % accordingly. In the \enquote{normal} case, we may have % reached \cs{q__@@_act_mark}, the end of the list. Then % leave \cs{c_zero} and the result in the input stream, % to terminate the expansion of \tn{romannumeral}. % Otherwise, apply the relevant function to the % \enquote{arguments}, |#3| % and to the head of the token list. Then repeat the loop. % The scheme is the same if the token list starts with a % group or with a space. Some extra work is needed to % make \cs{@@_act_space:wwnNNN} gobble the space. % \begin{macrocode} \cs_new:Npn \@@_act_loop:w #1 \q__@@_act_stop { \tl_if_head_is_N_type:nTF {#1} { \@@_act_normal:NwnNNN } { \tl_if_head_is_group:nTF {#1} { \@@_act_group:nwnNNN } { \@@_act_space:wwnNNN } } #1 \q__@@_act_stop } \cs_new:Npn \@@_act_normal:NwnNNN #1 #2 \q__@@_act_stop #3#4 { \if_meaning:w \q__@@_act_mark #1 \exp_after:wN \@@_act_end:wn \fi: #4 {#3} #1 \@@_act_loop:w #2 \q__@@_act_stop {#3} #4 } \cs_new:Npn \@@_act_end:wn #1 \@@_act_result:n #2 { \group_align_safe_end: \c_zero #2 } \cs_new:Npn \@@_act_group:nwnNNN #1 #2 \q__@@_act_stop #3#4#5 { #5 {#3} {#1} \@@_act_loop:w #2 \q__@@_act_stop {#3} #4 #5 } \exp_last_unbraced:NNo \cs_new:Npn \@@_act_space:wwnNNN \c_space_tl #1 \q__@@_act_stop #2#3#4#5 { #5 {#2} \@@_act_loop:w #1 \q__@@_act_stop {#2} #3 #4 #5 } % \end{macrocode} % Typically, the output is done to the right of what was already output, % using \cs{@@_act_output:n}, but for the \cs{@@_act_reverse} functions, % it should be done to the left. % \begin{macrocode} \cs_new:Npn \@@_act_output:n #1 #2 \@@_act_result:n #3 { #2 \@@_act_result:n { #3 #1 } } \cs_new:Npn \@@_act_reverse_output:n #1 #2 \@@_act_result:n #3 { #2 \@@_act_result:n { #1 #3 } } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}[EXP]{\tl_reverse:n, \tl_reverse:o, \tl_reverse:V} % \begin{macro}[EXP,aux]{\@@_reverse_normal:nN} % \begin{macro}[EXP,aux]{\@@_reverse_group_preserve:nn} % \begin{macro}[EXP,aux]{\@@_reverse_space:n} % The goal here is to reverse without losing spaces nor braces. % This is done using the general internal function \cs{@@_act:NNNnn}. % Spaces and \enquote{normal} tokens are output on the left of the current % output. Grouped tokens are output to the left but without any reversal % within the group. All of the internal functions here drop one argument: % this is needed by \cs{@@_act:NNNnn} when changing case (to record % which direction the change is in), but not when reversing the tokens. % \begin{macrocode} \cs_new:Npn \tl_reverse:n #1 { \etex_unexpanded:D \exp_after:wN { \tex_romannumeral:D \@@_act:NNNnn \@@_reverse_normal:nN \@@_reverse_group_preserve:nn \@@_reverse_space:n { } {#1} } } \cs_generate_variant:Nn \tl_reverse:n { o , V } \cs_new:Npn \@@_reverse_normal:nN #1#2 { \@@_act_reverse_output:n {#2} } \cs_new:Npn \@@_reverse_group_preserve:nn #1#2 { \@@_act_reverse_output:n { {#2} } } \cs_new:Npn \@@_reverse_space:n #1 { \@@_act_reverse_output:n { ~ } } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_reverse:N, \tl_reverse:c, \tl_greverse:N, \tl_greverse:c} % This reverses the list, leaving \cs{exp_stop_f:} in front, % which stops the \texttt{f}-expansion. % \begin{macrocode} \cs_new_protected:Npn \tl_reverse:N #1 { \tl_set:Nx #1 { \exp_args:No \tl_reverse:n { #1 } } } \cs_new_protected:Npn \tl_greverse:N #1 { \tl_gset:Nx #1 { \exp_args:No \tl_reverse:n { #1 } } } \cs_generate_variant:Nn \tl_reverse:N { c } \cs_generate_variant:Nn \tl_greverse:N { c } % \end{macrocode} % \end{macro} % % \subsection{The first token from a token list} % % \begin{macro}{\tl_head:N, \tl_head:n, \tl_head:V, \tl_head:v, \tl_head:f} % \begin{macro}[aux]{\@@_head_auxi:nw, \@@_head_auxii:nw} % \begin{macro}{\tl_head:w} % \begin{macro}{\tl_tail:N, \tl_tail:n, \tl_tail:V, \tl_tail:v, \tl_tail:f} % Finding the head of a token list expandably will always strip braces, which % is fine as this is consistent with for example mapping to a list. The % empty brace groups in \cs{tl_head:n} ensure that a blank argument gives an % empty result. The result is returned within the \tn{unexpanded} primitive. % The approach here is to use \cs{if_false:} to allow us to use |}| as % the closing delimiter: this is the only safe choice, as any other token % would not be able to parse it's own code. Using a marker, we can see if % what we are grabbing is exactly the marker, or there is anything else to % deal with. Is there is, there is a loop. If not, tidy up and leave the % item in the output stream. More detail in % \url{http://tex.stackexchange.com/a/70168}. % \begin{macrocode} \cs_new:Npn \tl_head:n #1 { \etex_unexpanded:D \if_false: { \fi: \@@_head_auxi:nw #1 { } \q_stop } } \cs_new:Npn \@@_head_auxi:nw #1#2 \q_stop { \exp_after:wN \@@_head_auxii:nw \exp_after:wN { \if_false: } \fi: {#1} } \cs_new:Npn \@@_head_auxii:nw #1 { \exp_after:wN \if_meaning:w \exp_after:wN \q_nil \tl_to_str:n \exp_after:wN { \use_none:n #1 } \q_nil \exp_after:wN \use_i:nn \else: \exp_after:wN \use_ii:nn \fi: {#1} { \if_false: { \fi: \@@_head_auxi:nw #1 } } } \cs_generate_variant:Nn \tl_head:n { V , v , f } \cs_new:Npn \tl_head:w #1#2 \q_stop {#1} \cs_new_nopar:Npn \tl_head:N { \exp_args:No \tl_head:n } % \end{macrocode} % To corrected leave the tail of a token list, it's important \emph{not} to % absorb any of the tail part as an argument. For example, the simple % definition % \begin{verbatim} % \cs_new:Npn \tl_tail:n #1 { \tl_tail:w #1 \q_stop } % \cs_new:Npn \tl_tail:w #1#2 \q_stop % \end{verbatim} % will give the wrong result for |\tl_tail:n { a { bc } }| (the braces will % be stripped). Thus the only safe way to proceed is to first check that % there is an item to grab (\emph{i.e.}~that the argument is not blank) and % assuming there is to dispose of the first item. As with \cs{tl_head:n}, % the result is protected from further expansion by \tn{etex_unexpanded:D}. % While we could optimise the test here, this would leave some tokens % \enquote{banned} in the input, which we do not have with this definition. % \begin{macrocode} \cs_new:Npn \tl_tail:n #1 { \etex_unexpanded:D \tl_if_blank:nTF {#1} { { } } { \exp_after:wN { \use_none:n #1 } } } \cs_generate_variant:Nn \tl_tail:n { V , v , f } \cs_new_nopar:Npn \tl_tail:N { \exp_args:No \tl_tail:n } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\str_head:n, \str_tail:n} % \begin{macro}[aux]{\__str_head:w} % \begin{macro}[aux]{\__str_tail:w} % After \cs{tl_to_str:n}, we have a list of character tokens, % all with category code 12, except the space, which has category % code 10. Directly using \cs{tl_head:w} would thus lose leading spaces. % Instead, we take an argument delimited by an explicit space, and % then only use \cs{tl_head:w}. If the string started with a % space, then the argument of \cs{__str_head:w} is empty, and % the function correctly returns a space character. Otherwise, % it returns the first token of |#1|, which is the first token % of the string. If the string is empty, we return an empty result. % % To remove the first character of \cs{tl_to_str:n} |{#1}|, % we test it using \cs{if_charcode:w} \cs{scan_stop:}, % always \texttt{false} for characters. If the argument was non-empty, % then \cs{__str_tail:w} returns everything until the first % \texttt{X} (with category code letter, no risk of confusing % with the user input). If the argument was empty, the first % \texttt{X} is taken by \cs{if_charcode:w}, and nothing % is returned. We use \texttt{X} as a \meta{marker}, rather than % a quark because the test \cs{if_charcode:w} \cs{scan_stop:} % \meta{marker} has to be \texttt{false}. % \begin{macrocode} \cs_new:Npn \str_head:n #1 { \exp_after:wN \__str_head:w \tl_to_str:n {#1} { { } } ~ \q_stop } \cs_new:Npn \__str_head:w #1 ~ % { \tl_head:w #1 { ~ } } \cs_new:Npn \str_tail:n #1 { \exp_after:wN \__str_tail:w \reverse_if:N \if_charcode:w \scan_stop: \tl_to_str:n {#1} X X \q_stop } \cs_new:Npn \__str_tail:w #1 X #2 \q_stop { \fi: #1 } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}[pTF]{\tl_if_head_eq_meaning:nN} % \begin{macro}[pTF]{\tl_if_head_eq_charcode:nN} % \begin{macro}[pTF]{\tl_if_head_eq_charcode:fN} % \begin{macro}[pTF]{\tl_if_head_eq_catcode:nN} % Accessing the first token of a token list is tricky in three cases: % when it has category code $1$ (begin-group token), when it is an % explicit space, with category code $10$ and character code $32$, or % when the token list is empty (obviously). % % Forgetting temporarily about this issue we would use the following % test in \cs{tl_if_head_eq_charcode:nN}. Here, \cs{tl_head:w} yields % the first token of the token list, then passed to \cs{exp_not:N}. % \begin{verbatim} % \if_charcode:w % \exp_after:wN \exp_not:N \tl_head:w #1 \q_nil \q_stop % \exp_not:N #2 % \end{verbatim} % The two first special cases are detected by testing if the token % list starts with an \texttt{N}-type token (the extra |?| sends empty % token lists to the \texttt{true} branch of this test). In those % cases, the first token is a character, and since we only care about % its character code, we can use \cs{str_head:n} to access it (this % works even if it is a space character). An empty argument will % result in \cs{tl_head:w} leaving two tokens: |?| which is taken in % the \cs{if_charcode:w} test, and \cs{use_none:nn}, which ensures % that \cs{prg_return_false:} is returned regardless of whether the % charcode test was \texttt{true} or \texttt{false}. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_eq_charcode:nN #1#2 { p , T , F , TF } { \if_charcode:w \exp_not:N #2 \tl_if_head_is_N_type:nTF { #1 ? } { \exp_after:wN \exp_not:N \tl_head:w #1 { ? \use_none:nn } \q_stop } { \str_head:n {#1} } \prg_return_true: \else: \prg_return_false: \fi: } \cs_generate_variant:Nn \tl_if_head_eq_charcode_p:nN { f } \cs_generate_variant:Nn \tl_if_head_eq_charcode:nNTF { f } \cs_generate_variant:Nn \tl_if_head_eq_charcode:nNT { f } \cs_generate_variant:Nn \tl_if_head_eq_charcode:nNF { f } % \end{macrocode} % For \cs{tl_if_head_eq_catcode:nN}, again we detect special cases % with a \cs{tl_if_head_is_N_type:n}. Then we need to test if the % first token is a begin-group token or an explicit space token, and % produce the relevant token, either \cs{c_group_begin_token} or % \cs{c_space_token}. Again, for an empty argument, a hack is used, % removing \cs{prg_return_true:} and \cs{else:} with \cs{use_none:nn} % in case the catcode test with the (arbitrarily chosen) |?| is % \texttt{true}. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_eq_catcode:nN #1 #2 { p , T , F , TF } { \if_catcode:w \exp_not:N #2 \tl_if_head_is_N_type:nTF { #1 ? } { \exp_after:wN \exp_not:N \tl_head:w #1 { ? \use_none:nn } \q_stop } { \tl_if_head_is_group:nTF {#1} { \c_group_begin_token } { \c_space_token } } \prg_return_true: \else: \prg_return_false: \fi: } % \end{macrocode} % For \cs{tl_if_head_eq_meaning:nN}, again, detect special cases. In % the normal case, use \cs{tl_head:w}, with no \cs{exp_not:N} this % time, since \cs{if_meaning:w} causes no expansion. With an empty % argument, the test is \texttt{true}, and \cs{use_none:nnn} removes % |#2| and the usual \cs{prg_return_true:} and \cs{else:}. % In the special cases, we know that the first token is a character, % hence \cs{if_charcode:w} and \cs{if_catcode:w} together are enough. % We combine them in some order, hopefully faster than the reverse. % Tests are not nested because the arguments may contain unmatched % primitive conditionals. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_eq_meaning:nN #1#2 { p , T , F , TF } { \tl_if_head_is_N_type:nTF { #1 ? } { \@@_if_head_eq_meaning_normal:nN } { \@@_if_head_eq_meaning_special:nN } {#1} #2 } \cs_new:Npn \@@_if_head_eq_meaning_normal:nN #1 #2 { \exp_after:wN \if_meaning:w \tl_head:w #1 { ?? \use_none:nnn } \q_stop #2 \prg_return_true: \else: \prg_return_false: \fi: } \cs_new:Npn \@@_if_head_eq_meaning_special:nN #1 #2 { \if_charcode:w \str_head:n {#1} \exp_not:N #2 \exp_after:wN \use:n \else: \prg_return_false: \exp_after:wN \use_none:n \fi: { \if_catcode:w \exp_not:N #2 \tl_if_head_is_group:nTF {#1} { \c_group_begin_token } { \c_space_token } \prg_return_true: \else: \prg_return_false: \fi: } } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}[pTF]{\tl_if_head_is_N_type:n} % The first token of a token list can be either an N-type argument, % a begin-group token (catcode 1), or an explicit space token % (catcode 10 and charcode 32). The latter two cases are characterized % by the fact that \cs{use:n} removes some tokens from |#1|, hence % changing its string representation (no token can have an empty % string representation). The extra brace group covers the case of % an empty argument, whose head is not \enquote{normal}. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_is_N_type:n #1 { p , T , F , TF } { \__str_if_eq_x_return:nn { \exp_not:o { \use:n #1 { } } } { \exp_not:n { #1 { } } } } % \end{macrocode} % \end{macro} % % \begin{macro}[EXP,pTF]{\tl_if_head_is_group:n} % Pass the first token of |#1| through \cs{token_to_str:N}, % then check for the brace balance. The extra \texttt{?} % caters for an empty argument.\footnote{Bruno: this could % be made faster, but we don't: if we hope to ever have % an e-type argument, we need all brace \enquote{tricks} % to happen in one step of expansion, keeping the token % list brace balanced at all times.} % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_is_group:n #1 { p , T , F , TF } { \if_catcode:w * \exp_after:wN \use_none:n \exp_after:wN { \exp_after:wN { \token_to_str:N #1 ? } } * \prg_return_false: \else: \prg_return_true: \fi: } % \end{macrocode} % \end{macro} % % \begin{macro}[EXP,pTF]{\tl_if_head_is_space:n} % \begin{macro}[EXP,aux]{\@@_if_head_is_space:w} % If the first token of the token list is an explicit space, i.e., % a character token with character code $32$ and category code $10$, % then this test will be \texttt{true}. It is \texttt{false} if the token % list is empty, if the first token is an implicit space token, % such as \cs{c_space_token}, or any token other than an explicit space. % The slightly convoluted approach with \tn{romannumeral} ensures that % each expansion step gives a balanced token list. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_head_is_space:n #1 { p , T , F , TF } { \tex_romannumeral:D \if_false: { \fi: \@@_if_head_is_space:w ? #1 ? ~ } } \cs_new:Npn \@@_if_head_is_space:w #1 ~ { \tl_if_empty:oTF { \use_none:n #1 } { \exp_after:wN \c_zero \exp_after:wN \prg_return_true: } { \exp_after:wN \c_zero \exp_after:wN \prg_return_false: } \exp_after:wN \use_none:n \exp_after:wN { \if_false: } \fi: } % \end{macrocode} % \end{macro} % \end{macro} % % \subsection{Viewing token lists} % % \begin{macro}{\tl_show:N, \tl_show:c} % Showing token list variables is done after checking that the % variable is defined (see \cs{__kernel_register_show:N}. % \begin{macrocode} \cs_new_protected:Npn \tl_show:N #1 { \cs_if_exist:NTF #1 { \cs_show:N #1 } { \__msg_kernel_error:nnx { kernel } { variable-not-defined } { \token_to_str:N #1 } } } \cs_generate_variant:Nn \tl_show:N { c } % \end{macrocode} %\end{macro} % % \begin{macro}{\tl_show:n} % The \cs{__msg_show_variable:n} internal function performs % line-wrapping, removes a leading \verb*|> |, then shows the result % using the \cs{etex_showtokens:D} primitive. Since \cs{tl_to_str:n} % is expanded within the line-wrapping code, the escape character is % always a backslash. % \begin{macrocode} \cs_new_protected:Npn \tl_show:n #1 { \__msg_show_variable:n { > ~ \tl_to_str:n {#1} } } % \end{macrocode} %\end{macro} % % \subsection{Scratch token lists} % % \begin{variable}{\g_tmpa_tl, \g_tmpb_tl} % Global temporary token list variables. % They are supposed to be set and used immediately, % with no delay between the definition and the use because you % can't count on other macros not to redefine them from under you. % \begin{macrocode} \tl_new:N \g_tmpa_tl \tl_new:N \g_tmpb_tl % \end{macrocode} % \end{variable} % % \begin{variable}{\l_tmpa_tl, \l_tmpb_tl} % These are local temporary token list variables. Be sure not to assume % that the value you put into them will survive for % long---see discussion above. % \begin{macrocode} \tl_new:N \l_tmpa_tl \tl_new:N \l_tmpb_tl % \end{macrocode} % \end{variable} % % \subsection{Deprecated functions} % % \begin{macro}{\tl_new:Nn, \tl_new:cn, \tl_new:Nx} % Use either \cs{tl_const:Nn} or \cs{tl_new:N}. % \begin{macrocode} %<*deprecated> \cs_new_protected:Npn \tl_new:Nn #1#2 { \tl_new:N #1 \tl_gset:Nn #1 {#2} } \cs_generate_variant:Nn \tl_new:Nn { c } \cs_generate_variant:Nn \tl_new:Nn { Nx } % % \end{macrocode} % \end{macro} % % \begin{macro}{\tl_gset:Nc} % \begin{macro}{\tl_set:Nc} % This was useful once, but nowadays does not make much sense. % \begin{macrocode} %<*deprecated> \cs_new_protected_nopar:Npn \tl_gset:Nc { \tex_global:D \tl_set:Nc } \cs_new_protected:Npn \tl_set:Nc #1#2 { \tl_set:No #1 { \cs:w #2 \cs_end: } } % % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_replace_in:Nnn, \tl_replace_in:cnn} % \begin{macro}{\tl_greplace_in:Nnn, \tl_greplace_in:cnn} % \begin{macro}{\tl_replace_all_in:Nnn, \tl_replace_all_in:cnn} % \begin{macro}{\tl_greplace_all_in:Nnn, \tl_greplace_all_in:cnn} % These are renamed. % \begin{macrocode} %<*deprecated> \cs_new_eq:NN \tl_replace_in:Nnn \tl_replace_once:Nnn \cs_new_eq:NN \tl_replace_in:cnn \tl_replace_once:cnn \cs_new_eq:NN \tl_greplace_in:Nnn \tl_greplace_once:Nnn \cs_new_eq:NN \tl_greplace_in:cnn \tl_greplace_once:cnn \cs_new_eq:NN \tl_replace_all_in:Nnn \tl_replace_all:Nnn \cs_new_eq:NN \tl_replace_all_in:cnn \tl_replace_all:cnn \cs_new_eq:NN \tl_greplace_all_in:Nnn \tl_greplace_all:Nnn \cs_new_eq:NN \tl_greplace_all_in:cnn \tl_greplace_all:cnn % % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_remove_in:Nn, \tl_remove_in:cn} % \begin{macro}{\tl_gremove_in:Nn, \tl_gremove_in:cn} % \begin{macro}{\tl_remove_all_in:Nn, \tl_remove_all_in:cn} % \begin{macro}{\tl_gremove_all_in:Nn, \tl_gremove_all_in:cn} % Also renamed. % \begin{macrocode} %<*deprecated> \cs_new_eq:NN \tl_remove_in:Nn \tl_remove_once:Nn \cs_new_eq:NN \tl_remove_in:cn \tl_remove_once:cn \cs_new_eq:NN \tl_gremove_in:Nn \tl_gremove_once:Nn \cs_new_eq:NN \tl_gremove_in:cn \tl_gremove_once:cn \cs_new_eq:NN \tl_remove_all_in:Nn \tl_remove_all:Nn \cs_new_eq:NN \tl_remove_all_in:cn \tl_remove_all:cn \cs_new_eq:NN \tl_gremove_all_in:Nn \tl_gremove_all:Nn \cs_new_eq:NN \tl_gremove_all_in:cn \tl_gremove_all:cn % % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_elt_count:n, \tl_elt_count:V, \tl_elt_count:o} % \begin{macro}{\tl_elt_count:N, \tl_elt_count:c} % Another renaming job. % \begin{macrocode} %<*deprecated> \cs_new_eq:NN \tl_elt_count:n \tl_count:n \cs_new_eq:NN \tl_elt_count:V \tl_count:V \cs_new_eq:NN \tl_elt_count:o \tl_count:o \cs_new_eq:NN \tl_elt_count:N \tl_count:N \cs_new_eq:NN \tl_elt_count:c \tl_count:c % % \end{macrocode} % \end{macro} % \end{macro} % % \begin{macro}{\tl_head_i:n} % \begin{macro}{\tl_head_i:w} % \begin{macro}{\tl_head_iii:n} % \begin{macro}{\tl_head_iii:f} % \begin{macro}{\tl_head_iii:w} % Two renames, and a few that are rather too specialised. % \begin{macrocode} %<*deprecated> \cs_new_eq:NN \tl_head_i:n \tl_head:n \cs_new_eq:NN \tl_head_i:w \tl_head:w \cs_new:Npn \tl_head_iii:n #1 { \tl_head_iii:w #1 \q_stop } \cs_generate_variant:Nn \tl_head_iii:n { f } \cs_new:Npn \tl_head_iii:w #1#2#3#4 \q_stop {#1#2#3} % % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % \end{macro} % % Deprecated on 2012-05-13 for removal by 2012-08-31. % % \begin{macro}{\tl_length_tokens:n} % \begin{macrocode} \cs_new_eq:NN \tl_length_tokens:n \tl_count_tokens:n % \end{macrocode} % \end{macro} % % Deprecated 2012-05-13 for removal by 2012-11-31. % % \begin{macro} % {\tl_length:N, \tl_length:c, \tl_length:n, \tl_length:V, \tl_length:o} % Renames. % \begin{macrocode} \cs_new_eq:NN \tl_length:N \tl_count:N \cs_new_eq:NN \tl_length:c \tl_count:c \cs_new_eq:NN \tl_length:n \tl_count:n \cs_new_eq:NN \tl_length:V \tl_count:V \cs_new_eq:NN \tl_length:o \tl_count:o % \end{macrocode} % \end{macro} % % Deprecated 2012-06-05 for removal after 2012-12-31. % % \begin{macro}[pTF]{\tl_if_empty:x} % We can test expandably the emptiness of an expanded token list % thanks to the primitive \tn{pdfstrcmp} which expands its argument: % a token list is empty if and only if its string representation is % empty. % \begin{macrocode} \prg_new_conditional:Npnn \tl_if_empty:x #1 { p , T , F , TF } { \__str_if_eq_x_return:nn { } {#1} } % \end{macrocode} % \end{macro} % % Deprecated 2012-07-08 for removal after 2012-10-31. % % \begin{macro}[EXP, pTF]{\tl_if_head_group:n} % \begin{macro}[EXP, pTF]{\tl_if_head_N_type:n} % \begin{macro}[EXP, pTF]{\tl_if_head_space:n} % \begin{macrocode} \prg_new_eq_conditional:NNn \tl_if_head_group:n \tl_if_head_is_group:n { p , T , F , TF } \prg_new_eq_conditional:NNn \tl_if_head_N_type:n \tl_if_head_is_N_type:n { p , T , F , TF } \prg_new_eq_conditional:NNn \tl_if_head_space:n \tl_if_head_is_space:n { p , T , F , TF } % \end{macrocode} % \end{macro} % \end{macro} % \end{macro} % % \begin{macro}{\tl_tail:w} % Deprecated 2012-09-01 for removal after 2012-12-31. This is broken as % it will strip braces from a case such as |a{bc}|. % \begin{macrocode} \cs_new:Npn \tl_tail:w #1#2 \q_stop {#2} % \end{macrocode} % \end{macro} % % % \begin{macrocode} % % \end{macrocode} % % \end{implementation} % % \PrintIndex