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% \iffalse
%% File: l3keyval.dtx Copyright (C) 2006-2009 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 ``expl3 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 LaTeX Project Team.
%%
%% -----------------------------------------------------------------------
%<*driver|package>
\RequirePackage{l3names}
%</driver|package>
%\fi
\GetIdInfo$Id: l3keyval.dtx 1412 2009-06-14 17:55:48Z joseph $
       {L3 Experimental keyval processing}
%\iffalse
%<*driver>
%\fi
\ProvidesFile{\filename.\filenameext}
  [\filedate\space v\fileversion\space\filedescription]
%\iffalse
\documentclass[full]{l3doc}
\begin{document}
\DocInput{l3keyval.dtx}
\end{document}
%</driver>
% \fi
%
%
% \title{The \textsf{l3keyval} package\thanks{This file
%         has version number \fileversion, last
%         revised \filedate.}\\
% Key-value parsing}
% \author{\Team}
% \date{\filedate}
% \maketitle
%
% \begin{documentation}
%
% \section{Introduction}
%
% Currently, this module only provides functions for extracting keys
% and values from a list. How this information is used is up to the
% programmer.
%
% A \meta{keyval list} is a list consisting of
% \begin{verbatim}
% key 1 = value 1 ,
% key 2           ,
% key 3 = value 3 ,
% \end{verbatim}
% 
% The function names for retrieving the keys and values are long but
% explain what they do. All these functions start with the name
% |\KV_parse_|. If a value is surrounded by braces, one level (and
% only one) is removed from the value. This is useful if you need to
% input a value which contains |=| or |,|. There are two primary
% actions we can take on a \meta{keyval list}.
% \begin{itemize}
% \item A \meta{keyval list} can be sanitized so that top level active
%   commas or equal signs are converted into catcode 12. When
%   declaring templates in the preamble one can probably safely assume
%   that there are no active commas or equals; these things should
%   only be active in the document. The name for this is either
%   |no_sanitize| or |sanitize|.
% \item Spaces on either side of a key or value can be trimmed. When
%   using the \LaTeX3 programming interface, spaces are automatically
%   ignored so there it would be a waste of time to search for extra
%   spaces since there would be none. At the document level however,
%   spaces must be removed. The name for this is either
%   |no_space_removal| or |space_removal|. Note that when
%   |space_removal| is called you get an additional option where you
%   can decide if one level of braces should be stripped from the key
%   and/or value; see the description of the boolean
%   |\l_KV_remove_one_level_of_braces_bool| for details.
% \end{itemize}
%
% During the parsing process, keys or values are not expanded and no
% |#|s are doubled.  When the parsing process is over, the keys and
% values are executed in the form
% \begin{quote}
% "\KV_key_value_elt:nn{key 1}{value 1}" \\
% "\KV_key_no_value_elt:n{key 2}"        \\
% "\KV_key_value_elt:nn{key 3}{value 3}"
% \end{quote}
% It is up to the programmer to provide a suitable definition of these
% two functions before starting the parsing process.
%
%
% \section{Functions}
%
% \begin{function}{
%     \KV_parse_no_space_removal_no_sanitize:n |
% }
%   \begin{syntax}
%     "\KV_parse_no_space_removal_no_sanitize:n" \Arg{keyval list}
%   \end{syntax}
%   Parses the keys and values literally. For use when spaces are
%   ignored and |=| and |,| have normal catcodes.
% \end{function}
%
% \begin{function}{
%     \KV_parse_space_removal_no_sanitize:n |
% }
%   \begin{syntax}
%     "\KV_parse_space_removal_no_sanitize:n" \Arg{keyval list}
%   \end{syntax}
%   As above but also removes spaces around keys and values. For use
%   when spaces are not ignored.
% \end{function}
%
% \begin{function}{
%     \KV_parse_space_removal_sanitize:n |
% }
%   \begin{syntax}
%     "\KV_parse_space_removal_sanitize:n" \Arg{keyval list}
%   \end{syntax}
%   As above but additionally also replaces top-level active |=| and
%   |,| with harmless versions.
% \end{function}
%
% \begin{variable}{
%     \l_KV_remove_one_level_of_braces_bool  |
% }
%   \begin{syntax}
%   \end{syntax}
%   This boolean controls whether or not one level of braces is
%   stripped from the key and value. The default value for this
%   boolean is \meta{true} so that exactly one level of braces is
%   stripped. For certain applications it is desirable to keep the
%   braces in which case the programmer just has to set the boolean
%   false temporarily. Setting this boolean has no effect when you
%   call the |no_space_removal| functions since not stripping braces
%   is a rare request and would clutter the otherwise elegant code of
%   the |no_space_removal| functions for very little gain. If you need
%   to preserve braces choose the slower |space_removal| functions.
% \end{variable}
%
% \begin{function}{
%     \KV_key_no_value_elt:n |
%     \KV_key_value_elt:nn |
% }
%   \begin{syntax}
%     "\KV_key_no_value_elt:n" \Arg{key} \\
%     "\KV_key_value_elt:n" \Arg{key} \Arg{value}
%   \end{syntax}
%   Functions returned by the |\KV_parse_| functions. The default
%   definition of these two functions is an error message!
% \end{function}
%
% \end{documentation}
%
% \begin{implementation}
%
% \section{\pkg{l3keyval} implementation}
%
% \subsection{Internal functions and variables}
%
% \begin{variable}{ \l_KV_tmpa_tl | \l_KV_tmpb_tl |
%                   \c_KV_single_equal_sign_tl |
%                   \l_KV_parse_toks | \l_KV_currkey_toks |
%                   \l_KV_currval_toks }
% Token list variables and token registers used internally.
% \end{variable}
%
% \begin{function}{ \KV_sanitize_outerlevel_active_equals:N |
%                   \KV_sanitize_outerlevel_active_commas:N }
% \begin{syntax}
% "\KV_sanitize_outerlevel_active_equals:N" <tl var.>
% \end{syntax}
% Replaces catcode other "=" and "," within a <tl var.> with active characters.
% \end{function}
%
% \begin{function}{ \KV_remove_surrounding_spaces:nw |
%                   \KV_remove_surrounding_spaces_auxi:w / (EXP) }
% \begin{syntax}
%
% "\KV_remove_surrounding_spaces:nw" <toks> <token list> "\q_nil"
% "\KV_remove_surrounding_spaces_auxi:w" <token list> \verb*" Q"$\sb3$
% \end{syntax}
%   Removes a possible
%   leading space plus a possible ending space from a <token list>.
%   The first version (which is not used in the code) stores it in <toks>.
% \end{function}
%
% \begin{function}{ \KV_add_value_element:w | \KV_set_key_element:w }
% \begin{syntax}
% "\KV_set_key_element:w" <token list> "\q_nil"
% "\KV_add_value_element:w" "\q_stop" <token list> "\q_nil"
% \end{syntax}
% Specialised functions to strip spaces from their input and set the
% token registers "\l_KV_currkey_toks" or "\l_KV_currval_toks"
% respectively.
% \end{function}
%
% \begin{function}{ \KV_split_key_value_current:w                      |
%                   \KV_split_key_value_space_removal:w                |
%                   \KV_split_key_value_space_removal_detect_error:wTF |
%                   \KV_split_key_value_no_space_removal:w             }
% \begin{syntax}
% "\KV_split_key_value_current:w" \dots
% \end{syntax}
% These functions split keyval lists into chunks depending which 
% sanitising method is being used. "\KV_split_key_value_current:w" is "\cs_set_eq:NN"
% to whichever is appropriate.
% \end{function}
%
% \subsection{Module code}
%
%    We start by ensuring that the required packages are loaded.
%    \begin{macrocode}
%<*package>
\ProvidesExplPackage
  {\filename}{\filedate}{\fileversion}{\filedescription}
\package_check_loaded_expl:
%</package>
%<*initex|package>
%    \end{macrocode}
%
%
% \begin{macro}{\l_KV_tmpa_tl}
% \begin{macro}{\l_KV_tmpb_tl}
% \begin{macro}{\c_KV_single_equal_sign_tl}
% Various useful things.
%    \begin{macrocode}
\tl_new:N  \l_KV_tmpa_tl
\tl_new:N  \l_KV_tmpb_tl
\tl_new:Nn \c_KV_single_equal_sign_tl{=}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\l_KV_parse_toks}
% \begin{macro}{\l_KV_currkey_toks}
% \begin{macro}{\l_KV_currval_toks}
% Some more useful things.
%    \begin{macrocode}
\toks_new:N \l_KV_parse_toks
\toks_new:N \l_KV_currkey_toks
\toks_new:N \l_KV_currval_toks
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\l_KV_remove_one_level_of_braces_bool}
% A boolean to control 
%    \begin{macrocode}
\bool_new:N \l_KV_remove_one_level_of_braces_bool
\bool_set_true:N \l_KV_remove_one_level_of_braces_bool
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\KV_sanitize_outerlevel_active_equals:N}
% \begin{macro}{\KV_sanitize_outerlevel_active_commas:N}
%   Some functions for sanitizing top level equals and commas. Replace
%   |=|$\sb{13}$ and |,|$\sb{13}$ with |=|$\sb{12}$ and |,|$\sb{12}$
%   resp.
%    \begin{macrocode}
\group_begin:
\char_set_catcode:nn{`\=}{13}
\char_set_catcode:nn{`\,}{13}
\char_set_lccode:nn{`\8}{`\=}
\char_set_lccode:nn{`\9}{`\,}
\tl_to_lowercase:n{\group_end:
\cs_new_nopar:Npn \KV_sanitize_outerlevel_active_equals:N #1{
  \tl_replace_all_in:Nnn #1 = 8
}
\cs_new_nopar:Npn \KV_sanitize_outerlevel_active_commas:N #1{
  \tl_replace_all_in:Nnn #1 , 9
}
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
%
%
%
% \begin{macro}{\KV_remove_surrounding_spaces:nw}
% \begin{macro}{\KV_remove_surrounding_spaces_auxi:w}
% \begin{macro}[aux]{\KV_remove_surrounding_spaces_auxii:w}
% \begin{macro}{\KV_set_key_element:w}
% \begin{macro}{\KV_add_value_element:w}
%   The macro |\KV_remove_surrounding_spaces:nw| removes a possible
%   leading space plus a possible ending space from its second
%   argument and stores it in the token register |#1|.
%
%   Based on Around the Bend No.~15 but with some enhancements. For
%   instance, this definition is purely expandable.
%
%   We use a funny token |Q|$\sb3$ as a delimiter.
%    \begin{macrocode}
\group_begin:
\char_set_catcode:nn{`\Q}{3}
%    \end{macrocode}
%    \begin{macrocode}
\cs_gnew:Npn\KV_remove_surrounding_spaces:nw#1#2\q_nil{
%    \end{macrocode}
% The idea in this processing is to use a Q with strange catcode to
% remove a trailing space. But first, how to get this expansion going?
%
% If you have read the fine print in the \textsf{l3expan} module,
% you'll know that the |f| type expansion will expand until the first
% non-expandable token is seen and if this token is a space, it will
% be gobbled. Sounds useful for removing a leading space but we also
% need to make sure that it does nothing but removing that space!
% Therefore we prepend the argument to be trimmed with an
% |\exp_not:N|. Now why is that? |\exp_not:N| in itself is an
% expandable command so will allow the |f| expansion to continue. If
% the first token in the argument to be trimmed is a space, it will be
% gobbled and the expansion stop. If the first token isn't a space,
% the |\exp_not:N| turns it temporarily into |\scan_stop:| which is
% unexpandable. The processing stops but the token following directly
% after |\exp_not:N| is now back to normal.
%
% The function here allows you to insert arbitrary functions in the
% first argument but they should all be with an |f| type
% expansion. For the application in this module, we use
% |\toks_set:Nf|.
%
% Once the expansion has been kick-started, we apply
% |\KV_remove_surrounding_spaces_auxi:w| to the replacement text of
% |#2|, adding a leading |\exp_not:N|. Note that no braces are
% stripped off of the original argument.
%    \begin{macrocode}
  #1{\KV_remove_surrounding_spaces_auxi:w \exp_not:N#2Q~Q}
}
%    \end{macrocode}
% |\KV_remove_surrounding_spaces_auxi:w| removes a trailing space if
% present, then calls |\KV_remove_surrounding_spaces_auxii:w| to clean
% up any leftover bizarre Qs. In order for
% |\KV_remove_surrounding_spaces_auxii:w| to work properly we need to
% put back a Q first.
%    \begin{macrocode}
\cs_gnew:Npn\KV_remove_surrounding_spaces_auxi:w#1~Q{
  \KV_remove_surrounding_spaces_auxii:w #1 Q
}
%    \end{macrocode}
% Now all that is left to do is remove a leading space which should be
% taken care of by the function used to initiate the expansion. Simply
% return the argument before the funny Q.
%    \begin{macrocode}
\cs_gnew:Npn\KV_remove_surrounding_spaces_auxii:w#1Q#2{#1}
%    \end{macrocode}
% 
% Here are some specialized versions of the above. They do exactly
% what we want in one go. First trim spaces from the value and then
% put the result surrounded in braces onto |\l_KV_parse_toks|.
%    \begin{macrocode}
\cs_gnew:Npn\KV_add_value_element:w\q_stop#1\q_nil{
  \toks_set:Nf\l_KV_currval_toks { 
    \KV_remove_surrounding_spaces_auxi:w \exp_not:N#1Q~Q
  }
  \toks_put_right:No\l_KV_parse_toks{
    \exp_after:wN {\toks_use:N \l_KV_currval_toks}
  }
}
%    \end{macrocode}
% When storing the key we firstly remove spaces plus the prepended
% |\q_no_value|.
%    \begin{macrocode}
\cs_gnew:Npn\KV_set_key_element:w#1\q_nil{
  \toks_set:Nf\l_KV_currkey_toks
  {
    \exp_last_unbraced:NNo \KV_remove_surrounding_spaces_auxi:w
      \exp_not:N \use_none:n #1Q~Q
  }
%    \end{macrocode}
% Afterwards we gobble an extra level of braces if that's what we are
% asked to do.  
%    \begin{macrocode}
  \bool_if:NT \l_KV_remove_one_level_of_braces_bool 
  {
    \exp_args:NNo \toks_set:No \l_KV_currkey_toks {
      \exp_after:wN \KV_add_element_aux:w 
        \toks_use:N \l_KV_currkey_toks \q_nil
    }
  }
}
\group_end:
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% 
% \begin{macro}[aux]{\KV_add_element_aux:w}
%   A helper function for fixing braces around keys and values.
%    \begin{macrocode}
\cs_new:Npn \KV_add_element_aux:w#1\q_nil{#1}
%    \end{macrocode}
% \end{macro}
%
%
% Parse a list of keyvals, put them into list form with entries like
% |\KV_key_no_value_elt:n{key1}| and |\KV_key_value_elt:nn{key2}{val2}|.
%
% \begin{macro}[aux]{\KV_parse_sanitize_aux:n}
%   The slow parsing algorithm sanitizes active commas and equal signs
%   at the top level first. Then uses |#1| as inspector of each
%   element in the comma list.
%    \begin{macrocode}
\cs_new:Npn \KV_parse_sanitize_aux:n #1 {
  \group_begin:
    \toks_clear:N \l_KV_parse_toks
    \tl_set:Nx \l_KV_tmpa_tl { \exp_not:n {#1} }
    \KV_sanitize_outerlevel_active_equals:N \l_KV_tmpa_tl
    \KV_sanitize_outerlevel_active_commas:N \l_KV_tmpa_tl
    \exp_last_unbraced:NNV \KV_parse_elt:w \q_no_value 
      \l_KV_tmpa_tl , \q_nil ,
%    \end{macrocode}
% We evaluate the parsed keys and values outside the group so the
% token register is restored to its previous value.
%    \begin{macrocode}
  \exp_last_unbraced:NV \group_end:
  \l_KV_parse_toks
}
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}[aux]{\KV_parse_no_sanitize_aux:n}
%   Like above but we don't waste time sanitizing. This is probably
%   the one we will use for preamble parsing where catcodes of |=| and
%   |,| are as expected!
%    \begin{macrocode}
\cs_new:Npn \KV_parse_no_sanitize_aux:n #1{
  \group_begin:
    \toks_clear:N \l_KV_parse_toks
    \KV_parse_elt:w \q_no_value #1 , \q_nil ,
  \exp_last_unbraced:NV \group_end:
  \l_KV_parse_toks
}
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}[aux]{\KV_parse_elt:w}
%   This function will always have a |\q_no_value| stuffed in as the
%   rightmost token in |#1|. In case there was a blank entry in the
%   comma separated list we just run it again. The |\use_none:n| makes
%   sure to gobble the quark |\q_no_value|. A similar test is made to
%   check if we hit the end of the recursion.
%    \begin{macrocode}
\cs_set:Npn \KV_parse_elt:w #1,{
  \tl_if_blank:oTF{\use_none:n #1}
  { \KV_parse_elt:w \q_no_value }
  {
    \quark_if_nil:oF {\use_ii:nn #1 }
%    \end{macrocode}
% If we made it to here we can start parsing the key and value. When
% done try, try again.
%    \begin{macrocode}
    {
      \KV_split_key_value_current:w #1==\q_nil
      \KV_parse_elt:w \q_no_value
    }
  }
}
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\KV_split_key_value_current:w}
% The function called to split the keys and values.
%    \begin{macrocode}
\cs_new:Npn \KV_split_key_value_current:w {\ERROR}
%    \end{macrocode}
% \end{macro}
%
% We provide two functions for splitting keys and values. The reason
% being that most of the time, we should probably be in the special
% coding regime where spaces are ignored. Hence it makes no sense to
% spend time searching for extra space tokens and we can do the
% settings directly. When comparing these two versions (neither doing
% any sanitizing) the |no_space_removal| version is more than 40\%
% faster than |space_removal|.
%
% It is up to functions like |\DeclareTemplate| to check which catcode
% regime is active and then pick up the version best suited for it.
%
%
%
% \begin{macro}{\KV_split_key_value_space_removal:w}
% \begin{macro}{\KV_split_key_value_space_removal_detect_error:wTF}
% \begin{macro}[aux]{\KV_split_key_value_space_removal_aux:w}
%   The code below removes extraneous spaces around the keys and
%   values plus one set of braces around the entire value.
%
%   Unlike the version to be used when spaces are ignored, this one
%   only grabs the key which is everything up to the first = and save
%   the rest for closer inspection. Reason is that if a user has
%   entered |mykey={{myval}},| then the outer braces have already been
%   removed before we even look at what might come after the key. So
%   this is slightly more tedious (but only slightly) but at least it
%   always removes only one level of braces.
%    \begin{macrocode}
\cs_new:Npn \KV_split_key_value_space_removal:w #1 = #2\q_nil{
%    \end{macrocode}
%   First grab the key.
%    \begin{macrocode}
  \KV_set_key_element:w#1\q_nil
%    \end{macrocode}
% Then we start checking. If only a key was entered, |#2| contains
% |=| and nothing else, so we test for that first.
%    \begin{macrocode}
  \tl_set:Nx\l_KV_tmpa_tl{\exp_not:n{#2}}
  \tl_if_eq:NNTF\l_KV_tmpa_tl\c_KV_single_equal_sign_tl
%    \end{macrocode}
% Then we just insert the default key.
%    \begin{macrocode}
  {
    \toks_put_right:No\l_KV_parse_toks{
      \exp_after:wN \KV_key_no_value_elt:n 
      \exp_after:wN {\toks_use:N\l_KV_currkey_toks}
    }
  }
%    \end{macrocode}
% Otherwise we must take a closer look at what is left. The remainder
% of the original list up to the comma is now stored in |#2| plus an
% additional |==|, which wasn't gobbled during the initial reading of
% arguments.  If there is an error then we can see at least one more
% |=| so we call an auxiliary function to check for this.
%    \begin{macrocode}
  {
    \KV_split_key_value_space_removal_detect_error:wTF#2\q_no_value\q_nil
    {\KV_split_key_value_space_removal_aux:w \q_stop #2}
    {\ERROR}
  }
}
%    \end{macrocode}
% The error test.
%    \begin{macrocode}
\cs_new:Npn
  \KV_split_key_value_space_removal_detect_error:wTF#1=#2#3\q_nil{
    \tl_if_head_eq_meaning:nNTF{#3}\q_no_value
}
%    \end{macrocode}
% Now we can start extracting the value. Recall that |#1| here starts
% with |\q_stop| so all braces are still there! First we try to see
% how much is left if we gobble three brace groups from |#1|. If |#1|
% is empty or blank, all three quarks are gobbled. If |#1| consists of
% exactly one token or brace group, only the latter quark is left.
%    \begin{macrocode}
\cs_new:Npn \KV_val_preserve_braces:NnN #1#2#3{{#2}}
\cs_new:Npn\KV_split_key_value_space_removal_aux:w #1=={
  \tl_set:Nx\l_KV_tmpa_tl{\exp_not:o{\use_none:nnn#1\q_nil\q_nil}}
  \toks_put_right:No\l_KV_parse_toks{
    \exp_after:wN \KV_key_value_elt:nn 
    \exp_after:wN {\toks_use:N\l_KV_currkey_toks}
  }
%    \end{macrocode}
% If there a blank space or nothing at all, |\l_KV_tmpa_tl| is now
% completely empty.
%    \begin{macrocode}
    \tl_if_empty:NTF\l_KV_tmpa_tl
%    \end{macrocode}
% We just put an empty value on the stack.
%    \begin{macrocode}
  { \toks_put_right:Nn\l_KV_parse_toks{{}} }
  {
%    \end{macrocode}
% If there was exactly one brace group or token in |#1|,
% |\l_KV_tmpa_tl| is now equal to |\q_nil|. Then we can just pick it
% up as the second argument of |#1|. This will also take care of any
% spaces which might surround it.
%    \begin{macrocode}
    \quark_if_nil:NTF\l_KV_tmpa_tl
    {
      \bool_if:NTF \l_KV_remove_one_level_of_braces_bool
      {
        \toks_put_right:No\l_KV_parse_toks{
          \exp_after:wN{\use_ii:nnn #1\q_nil}
        } 
      }
      {
        \toks_put_right:No\l_KV_parse_toks{
          \exp_after:wN{\KV_val_preserve_braces:NnN #1\q_nil}
        }
      }
    }
%    \end{macrocode}
% Otherwise we grab the value.
%    \begin{macrocode}
    { \KV_add_value_element:w #1\q_nil }
  }
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\KV_split_key_value_no_space_removal:w}
%   This version is for when in the special coding regime where spaces
%   are ignored so there is no need to do any fancy space hacks,
%   however fun they may be. Since there are no spaces, a set of
%   braces around a value is automatically stripped by \TeX.
%    \begin{macrocode}
\cs_new:Npn \KV_split_key_value_no_space_removal:w #1#2=#3=#4\q_nil{
  \tl_set:Nn\l_KV_tmpa_tl{#4}
  \tl_if_empty:NTF \l_KV_tmpa_tl
  {
    \toks_put_right:Nn\l_KV_parse_toks{\KV_key_no_value_elt:n{#2}}
  }
  {
    \tl_if_eq:NNTF\c_KV_single_equal_sign_tl\l_KV_tmpa_tl
    {
      \toks_put_right:Nn\l_KV_parse_toks{\KV_key_value_elt:nn{#2}{#3}}
    }
    {\ERROR}
  }
}
%    \end{macrocode}
% \end{macro}
%
%
%
% \begin{macro}{\KV_key_no_value_elt:n}
% \begin{macro}{\KV_key_value_elt:nn}
%    \begin{macrocode}
\cs_new:Npn \KV_key_no_value_elt:n #1{\ERROR}
\cs_new:Npn \KV_key_value_elt:nn #1#2{\ERROR}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% 
%
% \begin{macro}{\KV_parse_no_space_removal_no_sanitize:n}
%   Finally we can put all the things
%   together. |\KV_parse_no_space_removal_no_sanitize:n| is the
%   version that disallows unmatched conditional and does no space
%   removal.
%    \begin{macrocode}
\cs_new_nopar:Npn \KV_parse_no_space_removal_no_sanitize:n {
  \cs_set_eq:NN \KV_split_key_value_current:w \KV_split_key_value_no_space_removal:w
  \KV_parse_no_sanitize_aux:n
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\KV_parse_space_removal_sanitize:n}
% \begin{macro}{\KV_parse_space_removal_no_sanitize:n}
%   The other varieties can be defined in a similar manner. For the
%   version needed at the document level, we can use this one.
%    \begin{macrocode}
\cs_new_nopar:Npn \KV_parse_space_removal_sanitize:n {
  \cs_set_eq:NN \KV_split_key_value_current:w \KV_split_key_value_space_removal:w
  \KV_parse_sanitize_aux:n
}
%    \end{macrocode}
% For preamble use by the non-programmer this is probably best.
%    \begin{macrocode}
\cs_new_nopar:Npn \KV_parse_space_removal_no_sanitize:n {
  \cs_set_eq:NN \KV_split_key_value_current:w \KV_split_key_value_space_removal:w
  \KV_parse_no_sanitize_aux:n 
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
%    \begin{macrocode}
%</initex|package>
%    \end{macrocode}
% 
%    \begin{macrocode}
%<*showmemory>
\showMemUsage
%</showmemory>
%    \end{macrocode}
%
% \end{implementation}
% \PrintIndex
%
% \endinput