summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/source/latex/xbase/xparse.dtx
diff options
context:
space:
mode:
Diffstat (limited to 'Master/texmf-dist/source/latex/xbase/xparse.dtx')
-rw-r--r--Master/texmf-dist/source/latex/xbase/xparse.dtx2168
1 files changed, 0 insertions, 2168 deletions
diff --git a/Master/texmf-dist/source/latex/xbase/xparse.dtx b/Master/texmf-dist/source/latex/xbase/xparse.dtx
deleted file mode 100644
index 0ecd05af7bc..00000000000
--- a/Master/texmf-dist/source/latex/xbase/xparse.dtx
+++ /dev/null
@@ -1,2168 +0,0 @@
-% \iffalse
-%% File: xparse.dtx (C) Copyright 1999 Frank Mittelbach, Chris Rowley, David Carlisle
-%% (C) Copyright 2004-2007 Frank Mittelbach, 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 ``xbase 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/cgi-bin/cvsweb.cgi/
-%%
-%% 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 LaTeX Project Team.
-%%
-%% -----------------------------------------------------------------------
-%%
-%<*driver|package>
-\RequirePackage{l3names}
-%</driver|package>
-%\fi
-\GetIdInfo$Id: xparse.dtx 700 2007-11-27 14:18:29Z morten $
- {generic document command parser}
-%\iffalse
-%<*driver>
-%\fi
-\ProvidesFile{\filename.\filenameext}
- [\filedate\space v\fileversion\space\filedescription]
-%\iffalse
- \documentclass{ltxdoc}
- \usepackage[T1]{fontenc}
- \usepackage{textcomp}
- \makeatletter
- \providecommand*\eTeX{%
- \if b\expandafter\@car\f@series\@nil\boldmath\fi
- $\m@th\varepsilon$-\TeX}
- \makeatother
-% \usepackage{ldcdoc}
- \begin{document}
- \catcode`\_=11
- \catcode`\:=11
- \DocInput{xparse.dtx}
- \end{document}
-%</driver>
-% \fi
-%
-% \CheckSum{626}
-%
-%
-% \title{The \textsf{xparse} package\thanks{This file
-% has version number \fileversion, last
-% revised \filedate.}}
-% \author{FMi, CAR, DPC, MH}
-% \date{\copyright~\filedate}
-% \maketitle
-%
-% \begin{abstract}
-% The interfaces described in this document are not meant to be final
-% but only as a basis for discussion. Building productive applications
-% using the current code is discouraged.
-% \end{abstract}
-%
-% \section{Interface}
-%
-% This package implements high-level interface commands for class file
-% writers which allows the separation of formatting commands
-% (typically instances of so-called `templates') and their arguments
-% from the signature of document-level commands.
-%
-% This works by declaration commands that provide a general
-% specification method for the typical \LaTeX{} syntax, e.g.,
-% star-form, optional arguments, and mandatory arguments. A command
-% (or environment) declared in this way parses the input according to
-% its spec and presents its findings in a normalized way for further
-% processing.
-%
-% \subsection{Argument spec}
-%
-%
-% An argument specification is a list of letters each representing a
-% type of argument, i.e., |m| is a mandatory argument (surrounded by
-% braces), |o| an optional argument (surrounded by brackets if
-% present), and |s| represents a star (which might be present or not).
-% Thus the argument spec for headings as implemented by
-% |\@startsection| in standard \LaTeX{} would be represented by the
-% three letters |som|. Other argument types are available and can be
-% added at will. For a complete list of built-in argument types see
-% the next section.
-%
-% There is one important argument specifier worth taking note of. The
-% |P| does not behave as a normal argument specifier but allows the
-% next argument to take an argument containing the |\par| token which
-% is not allowed by default.
-%
-%
-% \subsection{Parsing results}
-%
-% To normalise the result of parsing the input according to an
-% argument specification it is important to uniquely identify all
-% arguments found. For this reason each parsing operation initiated by
-% one of the argument spec letters will result in an identifiable
-% output as follows:
-% \begin{description}
-% \item[m] will return the parsed argument surrounded by a brace
-% pair, i.e., will normally be the identity;
-% \item[o] will return the parsed argument surrounded by a brace pair
-% if present. Otherwise it will return the token |\NoValue|;
-% \item[O\{default\}] will return the parsed argument surrounded by a
-% brace pair if present. Otherwise it will return the |{default}|
-% as specified above.
-% \item[S\{\meta{symbol}\}] will return either the token |\c_true| or
-% |\c_false| depending on whether or not the next token is
-% \meta{symbol}.
-% \item[s] will return either the token |\c_true| or |\c_false|
-% depending on whether or not a star was parsed. This is just a
-% shorthand for |S{*}|.
-% \item[c] will parse the syntax |(|\meta{x}|,|\meta{y}|)|, i.e., a
-% coordinate pair and will return |{{|\meta{x}|}{|\meta{y}|}}| as
-% the result. If no open parentheses is scanned an error is
-% signalled.
-% \item[C\{\{x-default\}\{y-default\}\}] behaves like |c|, i.e.,
-% parses a coordinate pair if present. If the coordinate pair is
-% missing it returns the default values instead.
-% \item[l] Reads everything up to the first left brace as the
-% argument.
-% \end{description}
-% For example, given the spec |soomO{default}| the input
-% |*[Foo]{Bar}| would be parsed as
-% |\c_true{Foo}\NoValue{Bar}{default}|. In other words there will be
-% always exactly the same number of brace groups or tokens as the
-% number of letters in the argument spec.
-%
-% There are a few exceptions to this rule as the r\^ole of following
-% letters is to affect how the next argument is read.
-% \begin{description}
-% \item[>] takes a mandatory argument like |{P}| or |{PW}| and
-% inserts these extra argument specifiers so that they act on the
-% next regular argument type. See below.
-% \item[P] will cause the next argument to allow |\par| in it's
-% argument. Thus the specification |m>{P}mm| will cause the command to
-% read three mandatory arguments but only the second can contain the
-% |\par| token.
-% \item[W] will cause the next argument to \emph{not} ignore a space
-% when trying to scan ahead for a special symbol such as a |*| or an
-% optional argument. This is mostly useful when the last argument(s)
-% of a document command are optional (see example later on).
-% \end{description}
-%
-%
-% \subsection{Applying the parsing results}
-%
-% Since the result of the parsing is a well defined number of tokens or
-% brace groups it is easy to pass them on in any order to any
-% processing function. To this end the tokens or brace groups are
-% associated with the standard argument specifiers in \TeX{} macros,
-% i.e., |#1|, |#2|, and so forth. This limits the argument
-% specification to a maximum number of 9 letters, but for practical
-% applications this should be sufficient.
-%
-% \subsection{The class designer interface}
-%
-% This package provides commands for declaring commands
-% and environments to be used within the document body.
-%
-% \DescribeMacro\DeclareDocumentCommand
-% The |\DeclareDocumentCommand| declaration takes three arguments. The
-% first argument is the name of the command to be declared, the second
-% is the argument specification in the syntax described above, and the
-% third is the action to be carried out once the arguments are
-% parsed. Within the third argument |#1|, |#2|, etc.\ denote the
-% result of the parsing, e.g.,
-% \begin{verbatim}
-% \DeclareDocumentCommand{\chapter}{som}
-% { \IfBooleanTF {#1}
-% { \typesetnormalchapter {#2}{#3} }
-% { \typesetstarchapter {#3} }
-% }
-% \end{verbatim}
-% would be a way to define a |\chapter| command which would
-% essentially behave like the current \LaTeX{} command (except that it
-% would accept an optional argument even when a |*| was parsed). The
-% |\typesetnormalchapter| could test its first argument for being
-% |\NoValue| to see if an optional argument was present.
-%
-% Of course something like the |\IfNoValueTF| test could also be
-% placed inside a function that would process all three arguments, thus
-% using the templates and their instances as provided by the
-% \texttt{template} package such a declaration would probably look
-% more like the following example:
-% \begin{verbatim}
-% \DeclareDocumentCommand{\chapter}{som}
-% { \UseInstance {head} {A-head-main} {#1} {#2} {#3} }
-% \end{verbatim}
-%
-% Using the |\DeclareDocumentCommand| interface it is easy to modify
-% the document-level syntax while still applying the same
-% layout-generating functions, e.g., a class that would not support
-% optional arguments or star forms for the heading commands could
-% define |\chapter| like this:
-% \begin{verbatim}
-% \DeclareDocumentCommand{\chapter}{m}
-% { \UseInstance {head} {A-head-main} \BooleanFalse \NoValue {#1} }
-% \end{verbatim}
-% while a class that would allow for an additional optional argument
-% (for whatever reason) could define it like that:
-% \begin{verbatim}
-% \DeclareDocumentCommand{\chapter}{somo}
-% { \doSomethingWithTheExtraOptionalArg {#4}
-% \UseInstance {head} {A-head-main} {#1} {#2} {#3} }
-% \end{verbatim}
-% \DescribeMacro\ReDeclareDocumentCommand
-% \DescribeMacro\ProvideDocumentCommand
-% The commands |\ReDeclareDocumentCommand| and
-% |\ProvideDocumentCommand| work just like |\DeclareDocumentCommand|
-% with the exception that |\Re..| can only redefine an existing
-% command and |\Provide...| will only define the command if it is
-% already free.
-%
-%
-% \DescribeMacro\DeclareDocumentEnvironment
-% \DescribeMacro\ReDeclareDocumentEnvironment
-% \DescribeMacro\ProvideDocumentEnvironment The
-% |\DeclareDocumentEnvironment| declaration is similar to
-% |\DeclareDocumentCommand| except that it takes four arguments: the
-% first being the environment name (without a backslash), the second
-% again the argument-spec, and the third and forth are the actions
-% taken at start aqnd end of the environment. The parsed arguments are
-% available to both the start and the finish as |#1|, |#2|, etc.
-%
-% All commands and environments defined with the above commands are
-% automatically robust.
-%
-%
-%
-% \subsection{A different interface (for class design?)}
-%
-% Combining signature and top-level definition of a command |\foo| as
-% in
-% \begin{verbatim}
-% \DeclareDocumentCommand \foo { m c m }
-% { \typeout{1:#1}
-% \typeout{2:#2}
-% \typeout{3:#3}
-% }
-% \end{verbatim}
-% is fine in certain cases, e.g., if the user wants to declare a few
-% commands this way in the preamble of a document. However in a class
-% file it probably better to completely separate signature (i.e.,
-% argument \#1 and \#2) from top-level implementation (i.e., argument
-% \#3).
-%
-%
-% \begin{verbatim}
-% \DeclareDocumentCommandInterface \foo {bar} { m c m }
-% \end{verbatim}
-% The above now declare only the signature of the command |\foo| and
-% states that the implementation is to be found under the label |bar|.
-%
-% A bunch of such statements would then for the first time clearly
-% define a document class (i.e., what a document class instance needs
-% to define to be compliant).
-%
-% An instance would then consist of a lot of declarations of the type
-% \begin{verbatim}
-% \DeclareDocumentCommandImplementation {bar} {3}
-% { \typeout{1:#1}
-% \typeout{2:#2}
-% \typeout{3:#3}
-% }
-% \end{verbatim}
-% i.e., defining how to format things being referenced as part of the
-% signature.
-%
-% The functions |\DeclareDocumentCommandInterface| and
-% |\DeclareDocumentCommandImplementation| are implemented for now but
-% it is not sure if they will stay. If a document command is defined
-% with |\DeclareDocumentCommandInterface| but there is no matching
-% interface it prints the label in quotes as |``bar''|.
-%
-%
-%
-%
-% \subsection{Checking for a value or boolean}
-%
-% It would make perfect sense to make |\NoValue| a \LaTeX3 quark but
-% as there is a real danger of it getting executed by accident it is
-% best not to as it would result in an infinite loop.
-%
-% \DescribeMacro\NoValue
-% For this reason |\NoValue| is defined to expand to the string
-% |-NoValue-| which would get typeset if ever executed thus clearly
-% indicating the type of error the writer made.
-%
-% However this makes testing for this token slightly complicated as in
-% that case the test
-% \begin{verbatim}
-% \tlp_set:Nn \l_seen_tlp {#1}
-% \tlp_set:Nn \l_hidden_novalue_tlp {\NoValue}
-% \tlp_if_eq:NNTF \l_seen_tlp \l_hidden_novalue_tlp
-% \end{verbatim}
-% will be true if |#1| was |\NoValue| but false if |#1| itself
-% contains a macro which contains |\NoValue|; a case that happens
-% unfortunately very often in practice. Using an unguarded |x| type
-% expansion to define |\l_seen_tlp| is out of the question as |#1| is
-% typically either |\NoValue| or arbitrary user input for which we
-% can't properly guard it unless we are sure people only use robust
-% commands. When running a pure \LaTeX3 format where all document
-% commands are robust this is perhaps something to be looked at again
-% but when running on top of \LaTeXe{} we have to be careful.
-%
-% Therefore we use a somewhat different procedure here, which goes
-% like this:
-% \begin{enumerate}
-% \item Store |#1| in a temporary variable and check if it equals a
-% variable containing |\NoValue|. If true, execute the \meta{true}
-% code, otherwise go to~2.
-% \item Peek at the first token in |#1|. If this is a macro taking no
-% arguments expand |#1| once and go to~1. Otherwise execute the
-% \meta{false} code.
-% \end{enumerate}
-% The reason for the careful peeking ahead is that |#1| may very well
-% be a macro taking arguments and it is not certain that these
-% arguments are present! Hence this could lead to the well-known
-% \begin{verbatim}
-% Argument of \XXX has an extra }
-% \end{verbatim}
-% and we wouldn't want that\dots{} Goes without saying that this
-% procedure is quite tedious but usually it will exit after the first
-% time |#1| has been inspected. One additional test could be added,
-% namely that |#1| should also contain exactly one token but I don't
-% think that is going to matter much.
-%
-% \DescribeMacro\IfNoValueTF
-% \DescribeMacro\IfNoValueT
-% \DescribeMacro\IfNoValueF
-% \DescribeMacro\IfValueTF
-% \DescribeMacro\IfValueT
-% \DescribeMacro\IfValueF
-% These macros are used for checking if an optional argument was
-% present as in the example below.
-% \begin{verbatim}
-% \DeclareDocumentCommand\testcmd{om}{
-% \IfNoValueTF{#1}{``#2''}{#1,#2}
-% }
-% \end{verbatim}
-%
-%
-%
-% \DescribeMacro\IfBooleanTF
-% \DescribeMacro\IfBooleanT
-% \DescribeMacro\IfBooleanF
-% As mentioned earlier, the parsing result for a symbol argument like
-% |s| or |S{+}| is represented as the one of the tokens |\c_true| or
-% |\c_false| respectively. To test for these values the macro
-% |\IfBooleanTF| can be used. It expects as its first argument either
-% |\c_true| or |\c_false| and executes its second or third argument
-% depending on this value. |\IfBooleanT| and |\IfBooleanF| are
-% obvious shortcuts.
-%
-% At one point in time I thought that one can represent everything
-% using |\NoValue|, e.g., for the star case either return |*| or
-% |\NoValue|. However, this slows down processing of commands like
-% |\\*| considerably since they would then have to use a slower
-% internal test instead of a fast two-way switch.
-%
-%
-% \subsection{New argument types and shorthands}
-%
-% New argument types can be added at in a fairly straight forward
-% manner with the command
-% |\DeclareArgumentType|\DescribeMacro\DeclareArgumentType. This
-% command takes seven arguments: |#1| is a symbol denoting the
-% argument type, |#2| is the token the scanner should look for, |#3|
-% is one of the words |meaning|, |charcode| or |catcode| which is
-% handed down to the underlying |\peek_meaning:NTF| or
-% |\peek_charcode:NTF| etc. functions. For instance you can use the
-% |charcode| version if you want to pick up a literal |*| and not
-% just something that has the same \emph{meaning} as a regular
-% |*|. |#4| is for executing a special action (like an error message)
-% if no argument is found, |#5| is the default value in case of a
-% missing argument, |#6| is what the scanner will encounter, and
-% finally |#7| is what the scanner grabs from the argument type. This
-% is perhaps clearer with an example\dots{} This is how the |o| type
-% is implemented:
-% \begin{verbatim}
-% \DeclareArgumentType o [ {meaning} {} {\NoValue} {#1[#2]} {#2}
-% \end{verbatim}
-% In a similar fashion a |b| type expecting its argument inside |<|
-% and |>| would be defined as
-% \begin{verbatim}
-% \DeclareArgumentType b < {meaning} {} {\NoValue} {#1<#2>} {#2}
-% \end{verbatim}
-%
-% \DescribeMacro\DeclareArgumentTypeWithDefault
-% |\DeclareArgumentTypeWithDefault| is even simpler as this type
-% expects the default value to be input at the time of argument
-% specification. Thus arguments |#3| and |#4| from above are
-% unnecessary and are simply absent. Thus the |O| type is
-% implemented\footnote{I would say it is at best wishful thinking
-% that the interface could be something like
-% \texttt{\cs{DeclareArgumentTypeWithDefault}
-% C\{2\}\{meaning\}\{(\#1,\#2)\}\{\{\#1\}\{\#2\}\}} as it would
-% be quite troublesome implementation-wise and the current syntax
-% isn't that difficult to use.} as
-% \begin{verbatim}
-% \DeclareArgumentTypeWithDefault O [ {meaning}{#1[#2]} {#2}
-% \end{verbatim}
-% and again a similar |B| type could be implemented as
-% \begin{verbatim}
-% \DeclareArgumentTypeWithDefault B < {meaning}{#1<#2>} {#2}
-% \end{verbatim}
-%
-%
-% There is also a possibility to define a shorthand for a specific
-% sequence of arguments with the command
-% \DescribeMacro\DeclareArgumentTypeShorthand
-% |\DeclareArgumentTypeShorthand|. As an example the |s| argument
-% type is just a different way of saying |S{*}| so it's simply
-% implemented as
-% \begin{verbatim}
-% \DeclareArgumentTypeShorthand s {S{*}}
-% \end{verbatim}
-% Similarly one could add a shorthand |M| for inserting five
-% mandatory arguments where the latter is allowed to take |\par| in
-% its argument:
-% \begin{verbatim}
-% \DeclareArgumentTypeShorthand M {mmmm>{P}m}
-% \end{verbatim}
-%
-% Finally there is also the command
-% \DescribeMacro\DeclareSymbolArgument|\DeclareSymbolArgument| which
-% defines the low level interface to looking ahead for specific
-% symbols and removing them. For instance the |S| type argument is
-% declared as
-% \begin{verbatim}
-% \DeclareSymbolArgument S{meaning}
-% \end{verbatim}
-% So symbols picked up by this type will compare the meaning of the
-% tokens. One could do a
-% \begin{verbatim}
-% \DeclareSymbolArgument A{charcode}
-% \end{verbatim}
-% and then the |A| type would compare character codes instead. For
-% instance a command which expects a |+| symbol would return
-% \meta{true} if a |+| of any catcode is detected, not just catcode
-% 12 as is usual.
-%
-% \subsection{Some comments on the need for the \texttt{O} specifier}
-%
-% With |\newcommand| there is the possibility of specifying a default
-% for an optional argument which is stored away in a more or less
-% efficient manner. For example below is the old definition of
-% |\linebreak| as can be found in the \LaTeX2e kernel:
-%\begin{verbatim}
-%\def\linebreak{\@testopt{\@no@lnbk-}4}
-%\def\@no@lnbk #1[#2]{%
-% \ifvmode
-% \@nolnerr
-% \else
-% \@tempskipa\lastskip
-% \unskip
-% \penalty #1\@getpen{#2}%
-% \ifdim\@tempskipa>\z@
-% \hskip\@tempskipa
-% \ignorespaces
-% \fi
-% \fi}
-%\end{verbatim}
-% Ignoring for the moment that the above is slightly optimised an
-% expansion of this code under |\tracingall| will result in about 90
-% lines of tracing output. If we reimplement this using
-% |\DeclarDocumentCommand\linebreak{o}| we have to use |\IfNoValueTF|
-% to find out if an argument was present which (because of the careful
-% expansion we do internally) results in about twice as much of
-% tracing lines. In contrast using |O{4}| as below we end up with 110
-% lines, which seems roughly the price we have to pay for the extra
-% generality available (though this could perhaps even be reduced by a
-% better implementation of the parsing machine as originally done by
-% David, before i talked him into adding support for arguments in the
-% end code of an environment).\footnote{These comments were made
-% before the extensive changes in expl3 and xparse in 2005.}
-%
-%\begin{verbatim}
-%\DeclareDocumentCommand\linebreak { O{4} }
-% {
-% \ifvmode
-% \@nolnerr
-% \else
-% \@tempskipa\lastskip
-% \unskip
-% % \IfNoValueTF{#1}
-% % {\break}
-% % {\penalty -\@getpen{#1}}
-% \penalty -\@getpen{#1}
-% \ifdim\@tempskipa>\z@
-% \hskip\@tempskipa
-% \ignorespaces
-% \fi
-% \fi
-% }
-%\end{verbatim}
-%
-%
-% \subsection{A somewhat complicated example}
-%
-% This example reimplements the |\makebox| and |\framebox| interface
-% of \LaTeX{} both of which are unfortunately quite overloaded
-% syntactically. For this reason the example isn't meant to show good
-% coding practice but to show the power of the interface even though
-% applied in a somewhat bad way.
-%
-% |\makebox| and |\framebox| support the following different document
-% syntax forms:
-% \begin{itemize}
-% \item
-% |\makebox{A}|: only a single mandatory argument.
-%
-% \item
-% |\makebox[20pt]{B}|: one optional argument specify the box width.
-%
-%
-% \item
-% |\makebox[30pt][r]{C}|: two optional arguments the second specifying
-% the text position within the box being made (l,c,r being allowed
-% with c being the default).
-%
-% \item
-% |\makebox(20,30){D}|: within picture mode the width is specified not
-% as an optional argument in brackets but as a coordinate pair.
-%
-% \item
-% |\makebox(0,0)[lt]{E}|: in that case an optional argument following
-% coordinate pair denotes the placement within the box which can have
-% different values compared to case C above.
-% \end{itemize}
-%
-% To cater for this overloaded structure we can define |\makebox| to
-% be something like the following:
-%\begin{verbatim}
-%\DeclareDocumentCommand \makebox { C{\NoValue} o O{c} m}
-% { \IfNoValueTF{#1}
-% { \ltx@maketextbox{#2}{#3}{#4} }
-% { \ltx@makepicbox #1 {#2}{#4} } }
-%\end{verbatim}
-% In other words: if we do not see a coordinate pair first (i.e.,
-% first argument is |\NoValue| then we expect up to two optional
-% arguments (the width of the box or |\NoValue| if not given and the
-% placement specifier with a default of |c| if not given) and one
-% mandatory one which is the text. In that case we pass argument 2 to
-% 4 to an internal function |\ltx@maketextbox| which builds the text
-% box.
-%
-% Otherwise, if the first argument is a coordinate pair we parse an
-% optional argument denoting the placement specifier. Since
-% \texttt{xparse} doesn't support variant syntax we actually parse for
-% another optional argument (which has no meaning in that case and is
-% in fact ignored if present) followed by a mandatory one containing
-% the box text. In that case we pass the coordinate pair (|#1|), the
-% specifier (|#2|), and the text (|#4|) to the function
-% |\ltx@makepicbox| which builds the picture box. Note the special
-% handling of the coordinatesD: which are passed without surrounding
-% braces to |\ltx@makepicbox|: since the coordinate argument looks
-% like |{x-val}{y-val}| the receiving function |\ltx@makepicbox| gets
-% the |x-val| as argument one and the |y-val| as argument two.
-%
-% A definition for |\framebox| would look more or less identical
-% except that we would need to pass the arguments to slightly
-% different internal functions. The alternative is to give the
-% internal functions an extra argument that controls whether or not a
-% frame is bying built.
-%
-% \begin{macro}{\ltx@makepicbox}
-% So here is a possible implementation of |\ltx@makepicbox| that
-% builds a picture box with or without frame. It takes the following
-% mandatory arguments:
-% \begin{enumerate}
-% \item x-part of coordinate
-% \item y-part of coordinate
-% \item placement specifier, e.g., |lt| or |\NoValue|
-% \item text of box
-% \item the token |\frame| (if a frame should surround the box) or the
-% token |\@firstofone| --- not pretty i agree
-% \end{enumerate}
-%\begin{verbatim}
-%\def\ltx@makepicbox#1#2#3#4#5
-% {
-% #5{
-% \vbox to#2\unitlength
-% {\let\mb@b\vss \let\mb@l\hss\let\mb@r\hss
-% \let\mb@t\vss
-% \IfNoValueF{#3}
-% {
-% \@tfor\reserved@a :=#3\do{
-% \if s\reserved@a
-% \let\mb@l\relax\let\mb@r\relax
-% \else
-% \expandafter\let\csname mb@\reserved@a\endcsname\relax
-% \fi}%
-% }
-% \mb@t
-% \hb@xt@ #1\unitlength{\mb@l #4\mb@r}
-% \mb@b
-% \kern\z@}
-% }
-% }
-%\end{verbatim}
-% \end{macro}
-%
-%
-%
-% \begin{macro}{\ltx@maketextbox}
-% For the text case the internal function could take the following
-% mandatory arguments:
-% \begin{enumerate}
-% \item width of the box or |\NoValue| (denoting to build the box at
-% natural width)
-% \item placement specifier, e.g., |l|. (No test for |\NoValue| being undertaken)
-% \item text of box
-% \item the token |\fbox| (if a frame should surround the box) or the
-% token |\mbox|
-% \end{enumerate}
-% The actual code is taken straight from the current \LaTeX{} kernel
-% and looks kind of scary.
-%\begin{verbatim}
-%\def\ltx@maketextbox#1#2#3#4
-% {
-% \IfNoValueTF{#1}
-% {#4{#3}}
-% {
-% \leavevmode
-% \@begin@tempboxa\hbox{#3}
-% \setlength\@tempdima{#1}
-% \ifx#4\fbox
-% \setbox\@tempboxa\hb@xt@\@tempdima
-% {\kern\fboxsep\csname bm@#2\endcsname\kern\fboxsep}
-% \@frameb@x{\kern-\fboxrule}
-% \else
-% \hb@xt@\@tempdima{\csname bm@#2\endcsname}
-% \fi
-% \@end@tempboxa
-% }
-% }
-%\end{verbatim}
-% \end{macro}
-%
-% \begin{macro}{\makebox}
-% \begin{macro}{\framebox}
-% Given the above internal functions the declarations of |\makebox|
-% and |\framebox| would then look like this:
-%\begin{verbatim}
-%\DeclareDocumentCommand \makebox { C{\NoValue} o O{c} m}
-% { \IfNoValueTF{#1}
-% { \ltx@maketextbox{#2}{#3}{#4}\mbox }
-% { \ltx@makepicbox #1 {#2}{#4}\@firstofone } }
-%
-%\DeclareDocumentCommand \framebox { C{\NoValue} o O{c} m}
-% { \IfNoValueTF{#1}
-% { \ltx@maketextbox{#2}{#3}{#4}\fbox }
-% { \ltx@makepicbox #1 {#2}{#4}\frame } }
-%\end{verbatim}
-% \end{macro}
-% \end{macro}
-%
-%
-%
-% Here's another example which shows how one can use the |W| specifier.
-% The \textsf{amsmath} environments use their own definition of |\\|
-% which goes under the name |\math@cr|. As there is a good chance the
-% next line of math begins with either an asterisk or something in
-% square brackets this often leads to errors. The following example
-% definition works (I \emph{did} try it).
-% \begin{verbatim}
-% \ExplSyntaxOn
-% \makeatletter
-% \cs_gundefine:N \math@cr
-% \DeclareDocumentCommand\math@cr{>{W}s >{W}O{\z@}}{
-% \IfBooleanTF{#1}
-% { \global\@eqpen\@M }{
-% \global\@eqpen
-% \ifnum\dspbrk@lvl <\z@
-% \interdisplaylinepenalty
-% \else
-% -\@getpen\dspbrk@lvl
-% \fi
-% }
-% \math@cr@@@
-% \noalign{\vskip#2\relax}
-% }
-% \makeatother
-% \ExplSyntaxOn
-% \end{verbatim}
-% Note that this definition automatically avoids problems within the
-% alignments even if it is called as |\\&|.
-%
-%
-%
-%
-% \subsection{Open issues}
-%
-% In this section unresolved issues or ideas to think about and
-% perhaps implement are collected. There is no particular order to
-% them.
-%
-% \begin{itemize}
-% \item
-% Support for parsing verbatim type of arguments was considered (and
-% actually implemented at one stage. E.g.,
-% |g{|\meta{prepare-parsing}|}| where |g| first run
-% \meta{prepare-parsing} (which might involve |catcode|
-% changes)\footnote{urg horror!}, then look at the next token: if
-% that would be a |{| it would scan a brace delimited argument
-% (reverting catcodes of |{| and |}| if needed) otherwise would scan
-% for an argument delimited by that token so that something like
-% |\verb+%\+| would scan |%\| as its argument assuming that the
-% \meta{prepare-parsing} turned |%| and |\| into non-letters.
-%
-% All kind of nasty problems lurking especially no proper error
-% checks possible and of course as we all know such commands would
-% then not work inside arguments of other commands. At least they
-% would have some restrictions.
-%
-% Also no way to make the parsing smart by not accepting newlines as
-% part of the code (|\verb| does this right now and this is really
-% helpful as it catches runaways nicely).
-%
-%
-% \item
-% \textsf{xparse} should probably go into the \LaTeX3 kernel in which
-% case it should also provide the definitions of |\begin| and |\end|
-% and this raises a few questions: Will environments be defined as
-% control sequences |\foo| and |\endfoo|? If they are do we then want
-% to include support for a separate command |\foo| and if so what
-% about using the environment forms in special scanner mechanisms
-% where we \emph{can't} use |\begin{foo}|? In those cases one could
-% use a special command like what the \textsf{fancyvrb} package
-% provides with the command |\VerbatimEnvironment| and all packages
-% that define such special arguments should then also make sure that
-% the |\foo| command issued on its own should cause an error.
-% Another solution would be to simply define environments as
-% |\beginfoo| and |\endfoo| and then let |\begin| check if it was
-% used to call an environment or a command. If the latter is the
-% case then insert grouping as that could be handled by |\beginfoo|
-% itself. When |\end| is reached check if |\endfoo| exists. If it
-% does then use that, otherwise we were probably using a normal
-% command which should just close the group.
-% \end{itemize}
-%
-%
-% \subsection{Rejected ideas---and why}
-%
-% Let's say the document command |\testmo| has signature |mo|. If we
-% call it as |\testmo{arg} [opt]| a following space will be obeyed.
-% However calling it with the mandatory argument only as in
-% |\testmo{arg}| will gobble a following space because the peek ahead
-% in the |o| type ignores spaces. We can record that a space has been
-% gobbled when peeking ahead and we can also put it back in if needed
-% but I have only ever seen one request for this and in that case the
-% better solution was to use a signature |mWo| so that no spaces are
-% allowed between the mandatory and the optional argument. One could
-% even argue that this is the most appropriate thing to do if the user
-% is really that sensitive to spaces! In any case it is not
-% implemented here as it creates an unnecessary overhead for something
-% that is never used and a simple solution exists.
-%
-% \subsection{Experimental features}
-%
-% Experimental features in an experimental packages\dots{} Needless to
-% say that you can't rely on them staying!
-%
-%
-% One new feature is what I decided to call ``pseudo
-% arguments''. Strictly speaking these aren't real arguments but
-% instead read by removing a begin group token and then using
-% |\tex_aftergroup:D| to regain control. The definition of |\footnote|
-% in plain \TeX\ uses this so that people can use
-% |\verb| and the like inside the footnotes. The command
-% |\DeclarePseudoArgument|\DescribeMacro{\DeclarePseudoArgument} takes
-% four arguments: |#1| is a name for the pseudo argument, |#2| is the
-% number of arguments it takes, |#3| is the action to be taken right
-% before the left brace is removed and |#4| is what to be done when
-% the right brace has been read and we regain control. Note that both
-% |#3| and |#4| may use arguments! Here is a silly example:
-% \begin{verbatim}
-% \DeclarePseudoArgument{boxtest}{1}
-% {Before:~`#1',\hbox_set_inline_begin:N \l_tmpa_box }
-% {\hbox_set_inline_end: \text_put_sp: the~ box:~
-% \hbox_unpack_and_clear:N\l_tmpa_box ,~
-% After:~`#1'}
-% \end{verbatim}
-% Now when you want to use it, you simply call it with the macro
-% |\UsePseudoArgument|\DescribeMacro{\UsePseudoArgument}, which as its
-% first argument takes a name and the remaining depend on how many
-% arguments the pseudo argument was defined to have. Hence we could
-% use our |boxtest| definition like this:
-% \begin{verbatim}
-% \DeclareDocumentCommand\sillyboxtest{m}{
-% Testing~#1:~\UsePseudoArgument{boxtest}{#1}
-% }
-% \end{verbatim}
-% Then calling |\sillyboxtest{AB}{a\verb*+% $%&\+b}| produces
-% \begin{quote}
-% Testing AB: Before: `AB', the box:
-% a\verb*+% $%&\+b, After: `AB'
-% \end{quote}
-% |\UsePseudoArgument| should always come last in the document
-% command definition.
-%
-% \StopEventually{}
-%
-% \section{Implementation}
-%
-% Versions prior to and including 1.19 contained several different
-% implementations. These are gone now but can be looked at by
-% getting an older version of the package from the CVS repository.
-%
-% First the required packages.
-% \begin{macrocode}
-%<*package>
-\ProvidesExplPackage
- {\filename}{\filedate}{\fileversion}{\filedescription}
-\RequirePackage{l3tlp,l3num,l3toks,l3prg,l3int,l3seq,l3token}
-% \end{macrocode}
-%
-%
-%
-% \subsection{Error and warning messages}
-%
-% Here we define the error message we're going to use in this package.
-%
-% \begin{macro}{\xparse_already_defined_error_msg:N}
-% \begin{macro}{\xparse_not_yet_defined_error_msg:N}
-% \begin{macro}{\xparse_begins_with_end_error_msg:N}
-% \begin{macro}{\xparse_unknown_arg_type_error_msg:N}
-% \begin{macro}{\xparse_number_of_arguments_error_msg:Nn}
-% \begin{macro}{\xparse_no_command_implementation_warning:n}
-% The names should give the function's purpose away.
-% \begin{macrocode}
-\def_new:NNn \xparse_already_defined_error_msg:N 1 {
- \xparse_error:x {
- Command~name~`\token_to_string:N #1'~ already~defined!
- }
-}
-\def_new:NNn \xparse_not_yet_defined_error_msg:N 1 {
- \xparse_error:x {
- Command~`\token_to_string:N #1'~ not~ yet~defined!
- }
-}
-\def_new:NNn \xparse_begins_with_end_error_msg:N 1 {
- \xparse_error:x {
- Command~`\token_to_string:N #1'~begins~with~
- `\token_to_string:N \end'!
- }
-}
-% \end{macrocode}
-% This one is for when we've encountered an unknown argument type in
-% the argument specification. We can try to recover by putting in an
-% |m| type instead and hope for the best.
-% \begin{macrocode}
-\def_new:NNn \xparse_unknown_arg_type_error_msg:N 1{
- \xparse_error:x {
- Unknown~ argument~ type~ `#1'~
- I'll~ substitute~ it~ with~ `m'~ for~ now.~ Fingers~ crossed...
- }
-}
-% \end{macrocode}
-% A message for people using the wrong number of arguments.
-% \begin{macrocode}
-\def_new:NNn \xparse_no_command_implementation_warning:n 1 {
- \xparse_warning:x {No~ implementation~ for~ `#1'~ defined}
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\xparse_error:x}
-% \begin{macro}{\xparse_warning:x}
-% Here's how we produce the error messages and warnings currently.
-% This awaits a proper error message module!
-% \begin{macrocode}
-\def_new:NNn \xparse_error:x 1{\tex_errmessage:D {xparse~error:~#1}}
-\def_new:NNn \xparse_warning:x 1{\io_put_term:x{xparse~warning:~#1}}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-%
-% \subsection{Checking for valid command names}
-%
-%
-% \begin{macro}{\xparse_if_definable:NT}
-% \begin{macro}{\xparse_if_definable:cT}
-% A definable command is either |\c_undefined| or |\scan_stop:| and
-% furthermore we won't allow it to start with |\end|.
-% If the command is definable we do what was asked for otherwise
-% we give an appropriate error message.
-% \begin{macrocode}
-\def_new:NNn \xparse_if_definable:NTF 1 {
-% \end{macrocode}
-% First check if the control sequence is free.
-% \begin{macrocode}
- \cs_free:NTF #1
-% \end{macrocode}
-% If free check if it begins with |\end|.
-% \begin{macrocode}
- {
- \xparse_begins_with_end:NTF #1
- { \xparse_begins_with_end_error_msg:N #1 \use_arg_ii:nn }
- \use_arg_i:nn
- }
-% \end{macrocode}
-% If not free give an error message.
-% \begin{macrocode}
- { \xparse_already_defined_error_msg:N #1 \use_arg_ii:nn }
-}
-\def_new:NNn \xparse_if_definable:cTF 0 {
- \exp_args:Nc \xparse_if_definable:NTF
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \begin{macro}{\xparse_if_redefinable:NTF}
-% \begin{macro}{\xparse_if_redefinable:cTF}
-% A re-definable command is almost the same as above but here we
-% demand that it already exists.
-% \begin{macrocode}
-\def_new:NNn \xparse_if_redefinable:NTF 1 {
- \cs_free:NTF #1
- { \xparse_not_yet_defined_error_msg:N #1 \use_arg_ii:nn }
- {
- \xparse_begins_with_end:NTF #1
- { \xparse_begins_with_end_error_msg:N #1 \use_arg_ii:nn }
- \use_arg_i:nn
- }
-}
-\def_new:NNn \xparse_if_redefinable:cTF 0 {
- \exp_args:Nc \xparse_if_redefinable:NTF
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-% \begin{macro}{\xparse_begins_with_end:NTF}
-% \begin{macro}{\xparse_begins_with_end_aux:N}
-% Finally we need the magic function for checking if the control
-% sequence begins with |\end|.
-% We wish to determine if the control sequence in question begins with
-% |\end| which is forbidden. The end goal is to get a control sequence
-% consisting of the first three letters to test against |\end| with
-% |\cs_if_eq_name_p:NN|. The function |\cs_to_str:N| will remove the |\|
-% from a command name and return the rest of the characters with
-% category code 12. Thus using an |f| type expansion to get the first
-% three characters is perfectly safe as it'll stop right there. Then
-% we turn these three letters into a control sequence with a simple
-% expansion which is then tested with |\xparse_begins_with_end_aux:N|.
-% \begin{macrocode}
-\def_new:NNn \xparse_begins_with_end:NTF 1 {
-% \end{macrocode}
-% We do it all in a group as there is no need to fill up the hash
-% table with weird three letter control sequences.
-% \begin{macrocode}
- \group_begin:
- \exp_args:Nc \xparse_begins_with_end_aux:N {
- \tlist_head_iii:f { \cs_to_str:N #1 ??}
- }
-}
-% \end{macrocode}
-% After the above expansion tricks we now have a real control sequence
-% to test against |\end|. We end the group again.
-% \begin{macrocode}
-\def_new:NNn \xparse_begins_with_end_aux:N 1 {
- \if:w \cs_if_eq_name_p:NN #1 \end
- \group_end:
- \exp_after:NN \use_arg_i:nn
- \else:
- \group_end:
- \exp_after:NN \use_arg_ii:nn
- \fi:
-}
-% \end{macrocode}
-% Note that these definitions make no use of temporary variables.
-% \end{macro}
-% \end{macro}
-%
-%
-%
-% \subsection{The high level commands}
-%
-%
-% Here we set up the functions for defining and redefining document
-% commands and environments. It's all rather straight forward here so
-% I've saved on the comments.
-%
-% \begin{macro}{\DeclareDocumentCommand}
-% \begin{macro}{\ReDeclareDocumentCommand}
-% In case we can't do what the user wanted we gobble the next
-% arguments from the input stream. For commands there are two
-% arguments waiting.
-% \begin{macrocode}
-\def_new:NNn \DeclareDocumentCommand 1 {
- \xparse_if_definable:NTF #1
- { \xparse_declare_document_command:Nnn #1 }
- \use_none:nn
-}
-\def_new:NNn \ReDeclareDocumentCommand 1 {
- \xparse_if_redefinable:NTF #1
- { \xparse_declare_document_command:Nnn #1 }
- \use_none:nn
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\DeclareDocumentEnvironment}
-% \begin{macro}{\ReDeclareDocumentEnvironment}
-% Three arguments for environments.
-% \begin{macrocode}
-\def_new:NNn \DeclareDocumentEnvironment 1 {
- \xparse_if_definable:cTF {#1}
- { \xparse_declare_document_environment:nnnn {#1} }
- \use_none:nnn
-}
-\def_new:NNn \ReDeclareDocumentEnvironment 1 {
- \xparse_if_redefinable:cTF {#1}
- { \xparse_declare_document_environment:nnnn {#1} }
- \use_none:nnn
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\ProvideDocumentCommand}
-% \begin{macro}{\ProvideDocumentEnvironment}
-% When providing a command we just check if the control sequence is
-% free. If it is let |\DeclareDocument...| do the rest, otherwise
-% gobble the next arguments.
-% \begin{macrocode}
-\def_new:NNn \ProvideDocumentCommand 1{
- \cs_free:NTF #1
- { \DeclareDocumentCommand #1}
- \use_none:nn
-}
-\def_new:NNn \ProvideDocumentEnvironment 1{
- \cs_free:cTF {#1}
- { \DeclareDocumentEnvironment {#1} }
- \use_none:nnn
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-%
-% \subsection{The low level definitions}
-%
-%
-% First some helper functions
-% \begin{macro}{\l_xparse_grabbed_args_toks}
-% \begin{macro}{\l_xparse_end_environment_args_toks}
-% \begin{macro}{\l_xparse_mandatory_args_int}
-% \begin{macro}{\l_xparse_total_args_int}
-% We need some \meta{token} registers to keep track of things. We also
-% allocate an \meta{int} register to keep track of the number of
-% arguments.
-% \begin{macrocode}
-\toks_new:N \l_xparse_grabbed_args_toks
-\toks_new:N \l_xparse_end_environment_args_toks
-\int_new:N \l_xparse_mandatory_args_int
-\int_new:N \l_xparse_total_args_int
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \begin{macro}{\xparse_declare_document_command:Nnn}
-% \begin{macro}{\xparse_declare_document_command:cnn}
-% |\xparse_declare_document_command:Nnn| is a two step procedure. The
-% user level command |\|\meta{cmd} contains the argument grabbers
-% while the internal command |\\|\meta{cmd} holds the actual
-% definition of what to do with the arguments. Naturally this calls
-% for every such user level command to be robust which is done using
-% the \eTeX{} protection feature.
-% \begin{macrocode}
-\def_long:NNn \xparse_declare_document_command:Nnn 3{
-% \end{macrocode}
-% First we prepare the signature.
-% \begin{macrocode}
- \xparse_prepare_signature:n {#2}
-% \end{macrocode}
-% Now for the document command. Make it robust and make sure it starts
-% with |\toks_set:Nn \l_xparse_grabbed_args_toks {\\|\meta{cmd}|}|.
-% \begin{macrocode}
- \def_protected:Npx #1 {
- \exp_not:n { \toks_set:Nn \l_xparse_grabbed_args_toks }
- {\exp_not:c {\token_to_string:N #1}}
-% \end{macrocode}
-% Then add the argument grabbers which contain code gathered when
-% preparing the signature.
-% \begin{macrocode}
- \toks_use:N \l_xparse_grabbed_args_toks
-% \end{macrocode}
-% Finally execute |\toks_use:N \l_xparse_grabbed_args_toks| which now
-% holds the grabbed arguments enclosed in braces and starts with the
-% internal command |\\|\meta{cmd}.
-% \begin{macrocode}
- \exp_not:n{ \toks_use:N \l_xparse_grabbed_args_toks}
- }
-% \end{macrocode}
-% Define the internal command by making it a |\long| macro with number
-% of arguments equal to |\l_xparse_total_args_int| and definition as
-% given by |#3|. Even though this internal macro allows |\par| in its
-% argument the decision is left to the individual argument grabbers.
-% \begin{macrocode}
- \def_long:cNn {\token_to_string:N #1}\l_xparse_total_args_int{#3}
-}
-\def_new:Npn \xparse_declare_document_command:cnn {
- \exp_args:Nc \xparse_declare_document_command:Nnn
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\xparse_declare_document_environment:nnnn}
-% |\xparse_declare_document_environment:nnnn| is almost the same. In
-% order to use the grabbed arguments we take them from
-% |\l_xparse_grabbed_args_toks| just before they are executed. We
-% also insert a |\group_begin:| as it will otherwise fail miserably
-% in case a user tries to use it without |\begin ... \end|.
-% \begin{macrocode}
-\def_long_new:NNn \xparse_declare_document_environment:nnnn 4 {
- \xparse_declare_document_command:cnn {#1}{#2}
- { \group_begin:
- \toks_set_eq:NN \l_xparse_end_environment_args_toks
- \l_xparse_grabbed_args_toks
- #3
- }
-% \end{macrocode}
-% We let |\end|\meta{envir} equal to a standard version which will do
-% all the work.
-% \begin{macrocode}
- \let:cN {end #1} \xparse_parsed_end_environment:
-% \end{macrocode}
-% Now define |\end\\|\meta{envir}.
-% \begin{macrocode}
- \def_long:cNn {end \token_to_string:N \\ #1}
- \l_xparse_total_args_int{#4}
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_parsed_end_environment:}
-% \begin{macro}{\xparse_parsed_end_environment_aux:N}
-% |\end|\meta{envir} is set equal to |\xparse_parsed_end_environment:|
-% which then executes |\end\\|\meta{envir}. The |\\|\meta{envir} comes
-% from the argument grabbing. The remainder of the token list is the
-% grabbed arguments. We better make this robust as well.
-% \begin{macrocode}
-\def_protected_new:NNn \xparse_parsed_end_environment: 0{
- \exp_after:NN \xparse_parsed_end_environment_aux:N
- \toks_use:N \l_xparse_end_environment_args_toks
- \group_end:
-}
-\def_new:NNn \xparse_parsed_end_environment_aux:N 1{
- \cs_use:c {end \token_to_string:N #1 }
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsubsection{A class designer interface}
-%
-% Below is the implementation of |\DeclareDocumentCommandInterface|
-% and the close cousin |\DeclareDocumentCommandImplementation|.
-% It is an open issue whether this concept should be supported.
-%
-% \begin{macro}{\DeclareDocumentCommandInterface}
-% With this macro we define the document command |#1| to have
-% signature |#3| which does the argument grabbing. The arguments are
-% passed on to the internal command |\impl-#2|.
-% \begin{macrocode}
-\def_long_new:NNn \DeclareDocumentCommandInterface 3{
- \xparse_prepare_signature:n {#3}
- \def_protected:Npx #1 {
- \exp_not:n { \toks_set:Nn \l_xparse_grabbed_args_toks }
- {\exp_not:c {impl-#2}}
- \toks_use:N\l_xparse_grabbed_args_toks
- \exp_not:n{ \toks_use:N \l_xparse_grabbed_args_toks}
- }
-% \end{macrocode}
-% Define the internal command by making it a |\long| macro as we did
-% for |\DeclareDocumentCommand| but give it just a default definition
-% instead (usually an error message).
-% \begin{macrocode}
- \def_long:cNn {impl-#2} \l_xparse_total_args_int
- {\xparse_undefined_command_implementation:n{#2}}
-}
-% \end{macrocode}
-% \end{macro}
-% \begin{macro}{\xparse_undefined_command_implementation:n}
-% What to do if no implementation is made and the command is
-% called. Let's just typeset the name in quotes indicating that
-% something is wrong.
-% \begin{macrocode}
-\def_new:NNn \xparse_undefined_command_implementation:n 1{
- ``#1''
-% \ensuremath{\langle\textit{#1}\rangle}
- \xparse_no_command_implementation_warning:n {#1}
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\DeclareDocumentCommandImplementation}
-% Defines the internal command |\impl-#1| with |#2| arguments
-% and definition |#3|.
-% \begin{macrocode}
-\def_long_new:NNn \DeclareDocumentCommandImplementation 3{
- \def_long:cNn {impl-#1}#2{#3}
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{Creating the signature}
-%
-%
-% \begin{macro}{\xparse_prepare_signature:n}
-% The actual preparation of the signature is always the same but we
-% have different ways of handling it afterwards, so we make it a
-% separate function.
-% \begin{macrocode}
-\def_new:NNn \xparse_prepare_signature:n 1 {
-% \end{macrocode}
-% Initialize the counter taking care of the number of arguments. In
-% case we reach more than nine we will give an error message later on.
-% \begin{macrocode}
- \int_zero:N \l_xparse_total_args_int
-% \end{macrocode}
-% Clear the token register we use when building the signature and the
-% number of ``normal'' mandatory arguments. Also clear out the special
-% markers and initialize the two booleans to \meta{false}.
-% \begin{macrocode}
- \toks_clear:N \l_xparse_grabbed_args_toks
- \int_zero:N \l_xparse_mandatory_args_int
- \bool_gset_false:N \g_xparse_insert_marker_bool
- \bool_gset_false:N \g_xparse_allow_par_bool
- \tlp_gset_eq:NN \g_xparse_ignore_marker_tlp
- \g_xparse_ignore_spaces_marker_tlp
-% \end{macrocode}
-% Then call |\xparse_parse_signature:n|.
-% \begin{macrocode}
- \xparse_parse_signature:n #1 \q_nil
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{The argument types}
-%
-%
-%
-% All argument types must be denoted by single letters.\footnote{You
-% can use a multi-letter sequence to denote a shorthand but it
-% requires you to put two brace groups around it in the signature and
-% it's not officially supported.} We have three categories of letters:
-% Special markers, basic argument types, and shorthands.
-%
-% For certain argument types where we peek ahead in the token stream
-% we have a multitude of choices for how the macro should work:
-% Should it ignore spaces or other tokens? Which test should it use
-% for comparing tokens: meaning, catcode or charcode? Because of
-% these difficulties every argument that require peeking ahead must
-% be declared as one of the three test types.
-%
-% \subsubsection{Special markers}
-%
-% Since there are different markers that may be used at the same
-% time, we use the a special ``insert'' marker |>| to do this.
-%
-% \begin{macro}{\g_xparse_ignore_marker_tlp}
-% The current ignore marker is contained in this string.
-% \begin{macrocode}
-\tlp_new:Nn \g_xparse_ignore_marker_tlp {}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\g_xparse_ignore_marker_seq}
-% We start out by declaring a new sequence to contain all the
-% different types of ignore functions. Each element should be the
-% missing part of a |\peek_meaning|\meta{text}|:NTF| function.
-% \begin{macrocode}
-\seq_new:N \g_xparse_ignore_marker_seq
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\g_xparse_insert_marker_bool}
-% A boolean to check if we just saw an insert marker.
-% \begin{macrocode}
-\bool_new:N \g_xparse_insert_marker_bool
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_add_arg_type_>:}
-% The insert marker is called when this is seen. Is has a funny
-% definition but it works. |#1| is some test in the loop function
-% and |#2| is the list of markers.
-% \begin{macrocode}
-\def_new:cpn {xparse_add_arg_type_>:} #1
- \xparse_read_arg_type_or_grab_default:n #2{
-% \end{macrocode}
-% Insert pending |m| args first.
-% \begin{macrocode}
- \xparse_add_remaining_m_args:
-% \end{macrocode}
-% Then we set the boolean true and subtract one from the argument
-% count.
-% \begin{macrocode}
- \bool_gset_true:N \g_xparse_insert_marker_bool
- \int_decr:N \l_xparse_total_args_int
-% \end{macrocode}
-% Then go through the list and call each subtype if it exists.
-% \begin{macrocode}
- \tlist_map_inline:nn{#2}{
- \xparse_check_and_add_argument_type:N ##1
- }
-% \end{macrocode}
-% Finally call the loop again.
-% \begin{macrocode}
- \xparse_parse_signature:n
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_add_ignore_marker:Nnn}
-% A small function for adding a new ignore type marker.
-% \begin{macrocode}
-\def_new:NNn \xparse_add_ignore_marker:Nnn 3{
- \tlp_new:cn {g_xparse #2 _marker_tlp}{#3}
- \seq_gpush:NC \g_xparse_ignore_marker_seq {g_xparse #2 _marker_tlp}
- \def_new:cpn {xparse_add_arg_type_#1:}{
- \tlp_gset_eq:Nc \g_xparse_ignore_marker_tlp {g_xparse #2 _marker_tlp}
- }
-}
-% \end{macrocode}
-% \end{macro}
-% Here we add some ignore markers.
-% \begin{macrocode}
-\xparse_add_ignore_marker:Nnn W{_ignore_nothing}{}
-\xparse_add_ignore_marker:Nnn i{_ignore_spaces}{_ignore_spaces}
-\xparse_add_ignore_marker:Nnn I{_ignore_pars}{_ignore_pars}
-% \end{macrocode}
-%
-% \begin{macro}{\xparse_add_arg_type_P:}
-% This is simple, just set a boolean.
-% \begin{macrocode}
-\def_new:NNn \xparse_add_arg_type_P: 0{
- \bool_gset_true:N \g_xparse_allow_par_bool
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\g_xparse_allow_par_bool}
-% The boolean for allowing the |\par| token.
-% \begin{macrocode}
-\bool_new:N \g_xparse_allow_par_bool
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \begin{macro}{\xparse_parse_signature:n}
-% |\xparse_parse_signature:n| reads the signature one token/brace
-% group at a time and builds a list of argument grabbers which is
-% stored in |\l_xparse_grabbed_args_toks|. The function is recursive
-% which is why we use a quark to delimit it.
-% \begin{macrocode}
-\def_new:NNn \xparse_parse_signature:n 1{
-% \end{macrocode}
-% Check if we reached the end of the signature.
-% \begin{macrocode}
- \quark_if_nil:NTF #1
-% \end{macrocode}
-% If we did we may have pending |m| type arguments so we clear them
-% out here. Also check if the insert marker is true because if it is,
-% something is wrong. Otherwise we just continue.
-% \begin{macrocode}
- {
- \xparse_add_remaining_m_args:
- }
-% \end{macrocode}
-% Then proceed with adding arguments.
-% \begin{macrocode}
- {
- \int_incr:N \l_xparse_total_args_int
- \xparse_check_and_add_argument_type:N #1
-% \end{macrocode}
-% If the insert marker is true at this point we reset it again and
-% also disallow |\par| in arguments and make all |\peek| functions use
-% the |_ignore_spaces| versions.
-% \begin{macrocode}
- \bool_if:NT \g_xparse_insert_marker_bool
- {
- \bool_gset_false:N \g_xparse_insert_marker_bool
- \bool_gset_false:N \g_xparse_allow_par_bool
- \tlp_gset_eq:NN \g_xparse_ignore_marker_tlp
- \g_xparse_ignore_spaces_marker_tlp
- }
-% \end{macrocode}
-% After adding arguments we better set the boolean false in case we
-% don't have an insert marker.
-% \begin{macrocode}
-% \end{macrocode}
-% First we add the remaining |m| arguments.
-% \begin{macrocode}
-% \end{macrocode}
-% Then we run the loop again.
-% \begin{macrocode}
- \xparse_read_arg_type_or_grab_default:n
- }
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \begin{macro}{\xparse_check_and_add_argument_type:N}
-% This function checks if the argument type actually exists and gives
-% an error if it doesn't.
-% \begin{macrocode}
-\def_new:NNn \xparse_check_and_add_argument_type:N 1 {
- \cs_free:cTF {xparse_add_arg_type_#1:}
- { \xparse_unknown_arg_type_error_msg:N #1
- \int_incr:N \l_xparse_mandatory_args_int
- }
-% \end{macrocode}
-% Otherwise we just add it with its dedicated function.
-% \begin{macrocode}
- { \cs_use:c {xparse_add_arg_type_#1:} }
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-%
-% \begin{macro}{\xparse_read_arg_type_or_grab_default:n}
-% \begin{macro}{\xparse_grab_default_arg:n}
-% \begin{macro}{\xparse_grab_default_arg_allow_par:n}
-% The function for grabbing a default value. The default setting is
-% just to tun the loop again. However, some argument types need to
-% add a default argument so we add these as well.
-% \begin{macrocode}
-\let_new:NN \xparse_read_arg_type_or_grab_default:n
- \xparse_parse_signature:n
-\def_new:NNn \xparse_grab_default_arg:n 1{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks {{#1}}
- \let:NN \xparse_read_arg_type_or_grab_default:n
- \xparse_parse_signature:n
- \xparse_parse_signature:n
-}
-\def_long_new:NNn \xparse_grab_default_arg_allow_par:n 1{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks {{#1}}
- \let:NN \xparse_read_arg_type_or_grab_default:n
- \xparse_parse_signature:n
- \xparse_parse_signature:n
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-%
-%
-%
-%
-% \subsubsection{The default argument types}
-%
-%
-%
-% When scanning the signature we need to add the argument type which
-% is done by a function |\xparse_add_arg_type_|\meta{X}|:|, where
-% \meta{X} is the letter denoting the argument type. If not found an
-% error message is issued ny |\xparse_unknown_arg_type_error_msg:N|.
-%
-% By default the package implements the argument types |m|, |S|, |c|,
-% |C|, |o|, and |O| argument types as low level ones. The |s| type is
-% a shorthand as we shall see later.
-%
-% As we don't make every single |m| argument a separate grabber all
-% other types must clear out any pending |m|s.
-%
-% \paragraph{Mandatory arguments}
-%
-% Below follows the implementation of mandatory arguments.
-%
-% \begin{macro}{\xparse_add_arg_type_m:}
-% Check if the user asked for an |m| argument allowing |\par|
-% tokens and insert it. Otherwise increment the number of
-% non-|\long| argument grabbers.
-% \begin{macrocode}
-\def_new:Npn \xparse_add_arg_type_m: {
- \bool_if:NTF \g_xparse_allow_par_bool
- {
- \toks_put_right:Nn \l_xparse_grabbed_args_toks {\xparse_allow_par_m:w}
- }
- { \int_incr:N \l_xparse_mandatory_args_int }
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_add_remaining_m_args:}
-% And here is the function for clearing out normal pending |m|
-% arguments. There is little point in adding any arguments if none
-% are required.
-% \begin{macrocode}
-\def_new:Npn \xparse_add_remaining_m_args: {
- \int_compare:nNnF \l_xparse_mandatory_args_int = \c_zero
- {
- \toks_put_right:Nx \l_xparse_grabbed_args_toks {
- \exp_not:c{xparse_m
- \int_use:N \l_xparse_mandatory_args_int
- :w }
- }
- \int_zero:N \l_xparse_mandatory_args_int
- }
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \begin{macro}{\xparse_m1:w}
-% \begin{macro}{\xparse_m2:w}
-% \begin{macro}{\xparse_m3:w}
-% \begin{macro}{\xparse_m4:w}
-% \begin{macro}{\xparse_m5:w}
-% \begin{macro}{\xparse_m6:w}
-% \begin{macro}{\xparse_m7:w}
-% \begin{macro}{\xparse_m8:w}
-% \begin{macro}{\xparse_m9:w}
-% Grabbing 1--9 mandatory arguments. The one grabbing nine arguments
-% will automatically end with
-% |\toks_use:N \l_xparse_grabbed_args_toks| anyway so we avoid
-% problems with that one.
-% \begin{macrocode}
-\def_new:cpn {xparse_m1:w} #1 \l_xparse_grabbed_args_toks#2{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m2:w} #1 \l_xparse_grabbed_args_toks #2#3{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}{#3}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m3:w} #1 \l_xparse_grabbed_args_toks #2#3#4{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}{#3}{#4}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m4:w} #1 \l_xparse_grabbed_args_toks #2#3#4#5{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}{#3}{#4}{#5}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m5:w} #1 \l_xparse_grabbed_args_toks #2#3#4#5#6{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}{#3}{#4}{#5}{#6}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m6:w} #1 \l_xparse_grabbed_args_toks #2#3#4#5#6#7{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks
- {{#2}{#3}{#4}{#5}{#6}{#7}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m7:w} #1 \l_xparse_grabbed_args_toks#2#3#4#5#6#7#8{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks
- {{#2}{#3}{#4}{#5}{#6}{#7}{#8}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m8:w} #1\l_xparse_grabbed_args_toks
- #2#3#4#5#6#7#8#9{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks
- {{#2}{#3}{#4}{#5}{#6}{#7}{#8}{#9}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_new:cpn {xparse_m9:w} \toks_use:N \l_xparse_grabbed_args_toks
- #1#2#3#4#5#6#7#8#9{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks
- {{#1}{#2}{#3}{#4}{#5}{#6}{#7}{#8}{#9}}
- \toks_use:N \l_xparse_grabbed_args_toks
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\xparse_allow_par_m:w}
-% The |m| type allowing |\par| tokens. We only define one of them as
-% two in a row would be quite rare.
-% \begin{macrocode}
-\def_long_new:Npn \xparse_allow_par_m:w #1 \l_xparse_grabbed_args_toks#2{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}}
- #1 \l_xparse_grabbed_args_toks
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \paragraph{Arguments delimited by a left brace}
-%
-% \begin{macro}{\xparse_add_arg_type_l:}
-% \begin{macro}{\xparse_l:w}
-% \begin{macro}{\xparse_allow_par_l:w}
-% This is almost exactly the same as the |m| type except we read
-% everything up to the first left brace.
-% \begin{macrocode}
-\def_new:Npn \xparse_add_arg_type_l: {
- \xparse_add_remaining_m_args:
- \bool_if:NTF \g_xparse_allow_par_bool
- {
- \toks_put_right:Nn \l_xparse_grabbed_args_toks {\xparse_allow_par_l:w}
- }
- { \toks_put_right:Nn \l_xparse_grabbed_args_toks {\xparse_l:w} }
-}
-\def_new:Npn \xparse_l:w #1 \l_xparse_grabbed_args_toks#2#{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}}
- #1 \l_xparse_grabbed_args_toks
-}
-\def_long_new:Npn \xparse_allow_par_l:w #1 \l_xparse_grabbed_args_toks#2#{
- \toks_put_right:Nn \l_xparse_grabbed_args_toks{{#2}}
- #1 \l_xparse_grabbed_args_toks
-}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \paragraph{Adding a symbol argument type}
-%
-%
-% \begin{macro}{\DeclareSymbolArgument}
-% The actual grabber functions just issue a |\peek_meaning_remove:NTF|
-% or similar on the symbol chosen. If found, we put a |\c_true| on the
-% argument stack and |\c_false| otherwise.
-% \begin{macrocode}
-\def_new:NNn \DeclareSymbolArgument 2{
- \seq_map_variable:NNn \g_xparse_ignore_marker_seq \l_tmpa_tlp {
- \def:cpx {xparse \l_tmpa_tlp _#1:w}##1##2\l_xparse_grabbed_args_toks{
- \exp_not:c{peek_ #2 _remove \l_tmpa_tlp :NTF} ##1
- {
- \exp_not:N \toks_put_right:Nn \exp_not:N
- \l_xparse_grabbed_args_toks \exp_not:N \c_true
- ##2 \exp_not:N\l_xparse_grabbed_args_toks
- }
- {
- \exp_not:N \toks_put_right:Nn \exp_not:N
- \l_xparse_grabbed_args_toks \exp_not:N \c_false
- ##2 \exp_not:N\l_xparse_grabbed_args_toks
- }
- }
- }
-% \end{macrocode}
-% Implementing a symbol type is fairly straight forward. It needs to
-% grab a default argument. First we must clear out any pending |m|
-% arguments.
-% \begin{macrocode}
- \def:cpn {xparse_add_arg_type_#1:} {
- \xparse_add_remaining_m_args:
- \toks_put_right:Nx \l_xparse_grabbed_args_toks
- { \exp_not:c {xparse \g_xparse_ignore_marker_tlp _#1:w } }
-% \end{macrocode}
-% Nothing special when building the signature: We always grab a single
-% default argument.
-% \begin{macrocode}
- \let:NN \xparse_read_arg_type_or_grab_default:n \xparse_grab_default_arg:n
- }
-}
-% \end{macrocode}
-% It is this easy now:
-% \begin{macrocode}
-\DeclareSymbolArgument S{meaning}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \paragraph{Adding delimited arguments}
-%
-%
-% \begin{macro}{\DeclareArgumentType}
-% Argument types that read their argument delimited as the |o| type
-% can be defined with this function. |#1| is the letter associated
-% with the type, |#3| is the test type we should use, i.e.,
-% meaning, charcode or catcode. |#2| is the left delimiter \LaTeX{}
-% will look for, |#4| can be used for an error message or such in
-% case of a missing value, and |#5| the value inserted in case the
-% optional argument is missing. The last two arguments control how
-% the arguments are picked up and parsed on to the inner parsing.
-% \begin{macrocode}
-\def_new:NNn \DeclareArgumentType 7{
-% \end{macrocode}
-% For instance, we want |\DeclareArgumentType a{charcode}[...| to
-% define the function |\xparse_ignore_spaces_a:w| with meaning
-% |\peek_charcode_ignore_spaces:NTF [{...}{...}|. We want to define a
-% series of functions for each of these delimited argument types. One
-% for each of the |ignore| types plus an identical version of each of
-% these allowing the |\par| token in the argument. All the different
-% ignore types are stored in the sequence
-% |\g_xparse_ignore_marker_seq| so we go through that when doing the
-% definitions.
-% \begin{macrocode}
- \seq_map_variable:NNn \g_xparse_ignore_marker_seq \l_tmpa_tlp {
- \def:cpx {xparse \l_tmpa_tlp _#1:w}##1\l_xparse_grabbed_args_toks{
- \exp_not:c{peek_#3 \l_tmpa_tlp :NTF} \exp_not:N #2
- { \exp_not:c{xparse_#1_#3_help:nw}{##1} }
- {
- \exp_not:n {
- #4 \toks_put_right:Nn \l_xparse_grabbed_args_toks {#5}
- }
- ##1 \exp_not:N\l_xparse_grabbed_args_toks
- }
- }
-% \end{macrocode}
-% And now an almost identical version which allows the |\par| token.
-% \begin{macrocode}
- \def_long:cpx {xparse_allow_par \l_tmpa_tlp _#1:w}##1
- \l_xparse_grabbed_args_toks{
- \exp_not:c{peek_#3 \l_tmpa_tlp :NTF} \exp_not:N #2
- { \exp_not:c{xparse_allow_par_#1_#3_help:nw}{##1} }
- {
- \exp_not:n {
- #4 \toks_put_right:Nn \l_xparse_grabbed_args_toks {#5}
- }
- ##1 \exp_not:N\l_xparse_grabbed_args_toks
- }
- }
- }
-% \end{macrocode}
-% Here is the function for building the argument grabbing. We clear
-% out the remaining |m| arguments first.
-% \begin{macrocode}
- \def:cpn {xparse_add_arg_type_#1:} {
- \xparse_add_remaining_m_args:
- \toks_put_right:Nx \l_xparse_grabbed_args_toks {
- \exp_not:c {xparse
-% \end{macrocode}
-% Insert |_allow_par| in the csname if needed. This also applies to
-% the argument grabber (although this should probably just be the
-% default).
-% \begin{macrocode}
- \bool_if:NT \g_xparse_allow_par_bool {_allow_par}
- \g_xparse_ignore_marker_tlp
- _#1:w
- }
- }
- \let:NN \xparse_read_arg_type_or_grab_default:n \xparse_parse_signature:n
- }
-% \end{macrocode}
-% Now all we need to do is to define the helper functions.
-% \begin{macrocode}
- \xparse_define_helper:Nnnn #1{#3}{#6}{#7}
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\DeclareArgumentTypeDefaultValue}
-% The same as above but expects a default value in the signature.
-% Therefore it doesn't have the arguments of the default value and
-% what to do if it is missing like the above.
-% \begin{macrocode}
-\def_new:NNn \DeclareArgumentTypeDefaultValue 5{
- \seq_map_variable:NNn \g_xparse_ignore_marker_seq \l_tmpa_tlp {
- \def:cpx {xparse \l_tmpa_tlp _#1:w}##1##2\l_xparse_grabbed_args_toks{
- \exp_not:c{peek_#3 \l_tmpa_tlp :NTF} \exp_not:N #2
- { \exp_not:c{xparse_#1_#3_help:nw}{##2} }
- {
- \exp_not:N \toks_put_right:Nn
- \exp_not:N \l_xparse_grabbed_args_toks {{##1}}
- ##2 \exp_not:N \l_xparse_grabbed_args_toks
- }
- }
-% \end{macrocode}
-% And now an almost identical version which allows the |\par| token.
-% \begin{macrocode}
- \def_long:cpx {xparse_allow_par \l_tmpa_tlp _#1:w}##1##2
- \l_xparse_grabbed_args_toks{
- \exp_not:c{peek_#3 \l_tmpa_tlp :NTF} \exp_not:N #2
- { \exp_not:c{xparse_allow_par_#1_#3_help:nw}{##2} }
- {
- \exp_not:N \toks_put_right:Nn
- \exp_not:N \l_xparse_grabbed_args_toks {{##1}}
- ##2 \exp_not:N \l_xparse_grabbed_args_toks
- }
- }
- }
-% \end{macrocode}
-% Here is the function for building the argument grabbing. We clear
-% out the remaining |m| arguments first.
-% \begin{macrocode}
- \def:cpn {xparse_add_arg_type_#1:} {
- \xparse_add_remaining_m_args:
- \toks_put_right:Nx \l_xparse_grabbed_args_toks {
- \exp_not:c {xparse
-% \end{macrocode}
-% Insert |_allow_par| in the csname if needed. This also applies to
-% the argument grabber (although this should probably just be the
-% default).
-% \begin{macrocode}
- \bool_if:NT \g_xparse_allow_par_bool {_allow_par}
- \g_xparse_ignore_marker_tlp
- _#1:w
- }
- }
- \let:Nc \xparse_read_arg_type_or_grab_default:n
- {xparse_grab_default_arg
- \bool_if:NT \g_xparse_allow_par_bool {_allow_par}
- :n
- }
- }
-% \end{macrocode}
-% Now all we need to do is to define the helper functions.
-% \begin{macrocode}
- \xparse_define_helper:Nnnn #1{#3}{#4}{#5}
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_define_helper:Nnnn}
-% All we need now is the helper functions. We define a generic
-% interface that should be fairly easy to use.
-% \begin{macrocode}
-\def_new:NNn \xparse_define_helper:Nnnn 4{
- \toks_set:Nn \l_tmpa_toks
- {
- #3
- {
-% \end{macrocode}
-% Remember to add an extra set of braces here.
-% \begin{macrocode}
- \toks_put_right:Nn \l_xparse_grabbed_args_toks {{#4}}
- ##1 \l_xparse_grabbed_args_toks
- }
- }
-% \end{macrocode}
-% The next bit looks a little ugly but that's life.
-% \begin{macrocode}
- \toks_set:Nx \l_tmpa_toks {
- \exp_not:n {\def:cpn{xparse_#1_#2_help:nw}}
- \toks_use:N \l_tmpa_toks
- \exp_not:n {\def:cpn{xparse_allow_par_#1_#2_help:nw}}
- \toks_use:N\l_tmpa_toks
- }
- \toks_use:N \l_tmpa_toks
-}
-% \end{macrocode}
-% \end{macro}
-%
-% All the above may seem like an awful lot of trouble but it is
-% general and it allows the following simple definitions:
-% \begin{macrocode}
-\DeclareArgumentType o[{meaning}{}{\NoValue}{#1[#2]}{#2}
-% \end{macrocode}
-% For the |c| type we add give an error message.
-% \begin{macrocode}
-\DeclareArgumentType c({meaning}{
- \xparse_error:x{
- Missing~ coordinate~ argument.~ A~ value~ of~ (0,0)~ is~ assumed}
- }
- {{00}}
- {#1(#2,#3)}{{#2}{#3}}
-\DeclareArgumentTypeDefaultValue O[{meaning}{#1[#2]}{#2}
-\DeclareArgumentTypeDefaultValue C({meaning}{#1(#2,#3)}{{#2}{#3}}
-% \end{macrocode}
-% One could also do
-% \begin{verbatim}
-% \DeclareArgumentTypeDefaultValue O[{charcode}{#1#2#3]}{#3}
-% \end{verbatim}
-% where argument |#2| is the bracket but not requiring it to have
-% catcode~12. However we can't use the same trick for reading the end
-% of the argument.
-%
-% Another interesting one could be
-% \begin{verbatim}
-% \DeclareArgumentType a\c_group_begin_token{catcode}{}{\NoValue}{#1#2}{#2}
-% \end{verbatim}
-% which would basically be an optional argument in braces.
-%
-%
-%
-% \subsubsection{Argument shorthands}
-%
-%
-% \begin{macro}{\DeclareArgumentTypeShorthand}
-% Letting a letter or symbol be a shorthand for a more complicated
-% structure is rather easy actually. All we need to do is to gobble
-% the remainder of the main loop in the signature creation until
-% |\xparse_parse_signature:n|, decrement the argument counter, put
-% in the replacement argument specifiers and start the loop
-% again. The disadvantage of this scheme is that we have to cheat
-% and give it the wrong name as it should have a |w| argument
-% specification but I hope you can forgive this little white lie.
-% \begin{macrocode}
-\def_new:NNn \DeclareArgumentTypeShorthand 2{
- \def_new:cpn {xparse_add_arg_type_#1:}
- ##1 \xparse_read_arg_type_or_grab_default:n {
- \int_decr:N \l_xparse_total_args_int
- \xparse_read_arg_type_or_grab_default:n #2
- }
-}
-% \end{macrocode}
-% \end{macro}
-% \begin{macro}{\xparse_add_arg_type_s:}
-% Defining the |s| type is easy now since it really means |S{*}|.
-% \begin{macrocode}
-\DeclareArgumentTypeShorthand s {S{*}}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \subsection{Checking for optional values}
-%
-%
-% \begin{macro}{\IfBooleanTF}
-% \begin{macro}{\IfBooleanT}
-% \begin{macro}{\IfBooleanF}
-% The logical \meta{true} and \meta{false} statements are just our
-% normal |\c_true| and |\c_false| so testing for them is done with
-% our usual |\bool_if:NTF| functions from \textsf{l3prg}.
-% \begin{macrocode}
-\let_new:NN \IfBooleanTF \bool_if:NTF
-\let_new:NN \IfBooleanT \bool_if:NT
-\let_new:NN \IfBooleanF \bool_if:NF
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\NoValue}
-% \begin{macro}{\c_xparse_hidden_no_value_tlp}
-% |\NoValue| is just a text string and we define it as a token list
-% pointer. However we will actually test for token list pointers
-% with \emph{meaning} |\NoValue|. Hence if an argument is really
-% |-NoValue-| it will not be detected but that shouldn't happen.
-% \begin{macrocode}
-\tlp_new:Nn \NoValue {-NoValue-}
-\tlp_new:Nn \c_xparse_hidden_no_value_tlp {\NoValue}
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\xparse_if_no_value:nTF}
-% The test start by making a token list pointer out of the first
-% argument and then check if it is equal to
-% |\c_xparse_hidden_no_value_tlp| which contains |\NoValue|.
-% \begin{macrocode}
-\def_long_new:Npn \xparse_if_no_value:nTF #1{
- \tlp_set:Nx \l_tmpa_tlp{\exp_not:n{#1}}
- \tlp_if_eq:NNTF \l_tmpa_tlp \c_xparse_hidden_no_value_tlp
-% \end{macrocode}
-% If they are equal we just exit and execute the \meta{true} code.
-% \begin{macrocode}
- { \use_arg_i:nn }
-% \end{macrocode}
-% If not, take a closer look at |#1|. Peek ahead at the first token in
-% |#1| and then call the function |\xparse_if_no_value_aux:| but only
-% if |#1| is not empty or a blank space: in that case we can execute
-% the \meta{false} code immediately. We must use this test at some
-% point otherwise the macros for checking tokens will break since the
-% argument may be empty.
-% \begin{macrocode}
- { \tlist_if_blank:nTF {#1}
- { \use_arg_ii:nn }
- {\peek_after:NN \xparse_if_no_value_aux: #1 \q_nil {#1} }
- }
-}
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\xparse_if_no_value_aux:}
-% Now we simply check the argument specification of the token. If
-% it is not a macro the function |\token_get_arg_spec:N| returns
-% |\scan_stop:|.
-% \begin{macrocode}
-\def_long_new:Npn \xparse_if_no_value_aux: {
- \tlp_set:Nx \l_tmpa_tlp{\token_get_arg_spec:N \l_peek_token }
-% \end{macrocode}
-% Then check if |\l_tmpa_tlp| is empty, because this means we have a
-% macro taking zero arguments and we can expand it once
-% safely. Otherwise we just exit and execute the false code. Remember
-% that we have the sequence |{#1}| waiting after the |\q_nil| in
-% |\xparse_if_no_value:nTF| above.
-% \begin{macrocode}
- \tlp_if_empty:NTF \l_tmpa_tlp
- {\use_arg_i_delimit_by_q_nil:nw {\exp_args:No\xparse_if_no_value:nTF}}
- {\use_arg_i_delimit_by_q_nil:nw {\use_arg_iii:nnn}}
-}
-% \end{macrocode}
-% \end{macro}
-%
-%
-% \begin{macro}{\IfNoValueTF}
-% \begin{macro}{\IfNoValueT}
-% \begin{macro}{\IfNoValueF}
-% \begin{macro}{\IfValueTF}
-% \begin{macro}{\IfValueT}
-% \begin{macro}{\IfValueF}
-% |\IfNoValueTF| and its varieties are implemented as subcases of
-% |\xparse_if_no_value:nTF|.
-% \begin{macrocode}
-\let_new:NN \IfNoValueTF \xparse_if_no_value:nTF
-\def_long_new:NNn \IfNoValueT 2 {\xparse_if_no_value:nTF{#1}{#2}{}}
-\def_long_new:NNn \IfNoValueF 1 {\xparse_if_no_value:nTF {#1}{}}
-% \end{macrocode}
-% For |\IfValueTF| we just reverse the arguments.
-% \begin{macrocode}
-\def_long_new:NNn \IfValueTF 3{\xparse_if_no_value:nTF {#1}{#3}{#2}}
-\let_new:NN \IfValueT \IfNoValueF
-\let_new:NN \IfValueF \IfNoValueT
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-%
-% \subsection{Pseudo arguments}
-%
-% \begin{macro}{\l_xparse_pseudo_post_arg_tlp}
-% A temporary token list pointer to store the post-arguments.
-% \begin{macrocode}
-\tlp_new:Nn \l_xparse_pseudo_post_arg_tlp {}
-% \end{macrocode}
-% \end{macro}
-% \begin{macro}{\DeclarePseudoArgument}
-% Must be called at the end of the replacement text. Can use the
-% parameters picked up so far. |#1| is a name for it, |#2| is the
-% number of arguments, |#3| is the pre-argument definition, |#4| is
-% the post-argument definition. The idea here is to define two
-% functions: One to execute before the special pseudo argument is
-% found and one to to it afterwards. Hence we define such two
-% functions with |#2| arguments and definitions |#3| and |#4|
-% respectively.
-% \begin{macrocode}
-\def_long_new:NNn \DeclarePseudoArgument 4{
- \def_long:cNn {xparse_pseudo_pre_arg_#1:\prg_replicate:nn{#2}{n}}#2{#3}
- \def_long:cNn {xparse_pseudo_post_arg_#1:\prg_replicate:nn{#2}{n}}#2{#4}
-% \end{macrocode}
-% In case the user doesn't put the argument in braces, it must be a
-% single token which we just grab and then execute the
-% post-argument. Surely it won't be a |\par| token!
-% \begin{macrocode}
- \def:cNn {xparse_pseudo_nobrace_arg_#1:N} 1 {
- ##1 \l_xparse_pseudo_post_arg_tlp
- }
-% \end{macrocode}
-% The regular version of the command is then this:
-% \begin{enumerate}
-% \item Execute the pre-code at level $n$.
-% \item Store the post-code in a token list pointer at level $n$.
-% \item Look for a begin-group token.
-% \item[4a] If found, remove it, start a group (level $n+1$) and make
-% sure the token list pointer from 2) is executed after the group
-% has ended (at level $n$).
-% \item[4b] If not found, call the |nobrace_arg| version which also
-% executes the token list pointer from 2) at level $n$.
-% \end{enumerate}
-% This scheme enables these commands to be nested since they all
-% appear at different grouping levels.
-%
-% Next we define the function. Also make sure that it gets all the
-% arguments carried over to the post-argument.
-% \begin{macrocode}
- \def_long:cNx {xparse_pseudo_arg_#1:w} #2
- {
- \exp_not:c {
- xparse_pseudo_pre_arg_#1: \prg_replicate:nn{#2}{n}
- }
- \cs_use:c{def_aux_use_\int_use:N \int_eval:n{#2}_parameter:}
- \exp_not:n {\tlp_set:Nn \l_xparse_pseudo_post_arg_tlp}
- {
- \exp_not:c {xparse_pseudo_post_arg_#1:\prg_replicate:nn{#2}{n}}
- \cs_use:c{def_aux_use_\int_use:N \int_eval:n{#2}_parameter:}
- }
- \exp_not:n{ \peek_catcode_remove_ignore_spaces:NTF \c_group_begin_token }
- {
-% \end{macrocode}
-% Here we insert the left brace token which was removed removed.
-% In case you're wondering then yes, I know that |\c_group_begin_token|
-% and |\group_execute_after:N| are unexpandable but I prefer this method
-% because I don't want to remember which commands are expandable and
-% which are not.
-% \begin{macrocode}
- \exp_not:n {
- \c_group_begin_token
- \group_execute_after:N \l_xparse_pseudo_post_arg_tlp
- }
- }
- {
- \exp_not:c{xparse_pseudo_nobrace_arg_#1:N}
- }
- }
-}
-% \end{macrocode}
-% \end{macro}
-% \begin{macro}{\UsePseudoArgument}
-% Just a nice wrapper for calling such an argument.
-% \begin{macrocode}
-\def_new:NNn \UsePseudoArgument 1{\cs_use:c{xparse_pseudo_arg_#1:w}}
-% \end{macrocode}
-% \end{macro}
-%
-%
-%
-%
-% \Finale
-%
-\endinput
-%
-% $Log$
-% Revision 1.25 2006/07/17 22:25:53 morten
-% Minor change to reflect change in l3basics.dtx
-%
-% Revision 1.24 2006/07/08 22:44:29 morten
-% Fixed two lurking problems in \xparse_if_no_value:nTF.
-%
-% Revision 1.23 2006/07/06 14:56:04 morten
-% Change to use new \def:NNn syntax
-%
-% Revision 1.22 2006/01/17 23:04:08 morten
-% Added `l' type argument for reading up to a left brace.
-%
-% Revision 1.21 2006/01/04 02:42:35 morten
-% Changed RCS information retrieval. Rewrote \DeclareArgumentType and
-% its relatives in order for them to work properly with the new \peek_
-% functions. Changed how special markers are inserted into the
-% signature. Added `pseudo arguments'. Updated documentation to reflect
-% all these changes. And more which I can't remember right now :-)
-%
-% Revision 1.20 2005/04/06 21:24:47 morten
-% Total rewrite - there is only one implementation in the package
-% now. Documentation updated to match the changes.
-%
-%
-%