summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/source/latex/l3kernel/l3keyval.dtx
blob: 999ae7e5b08711480156a771f98d39bf8f4e406c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
% \iffalse meta-comment
%
%% File: l3keyval.dtx Copyright (C) 2006-2011 The LaTeX3 Project
%%
%% It may be distributed and/or modified under the conditions of the
%% LaTeX Project Public License (LPPL), either version 1.3c of this
%% license or (at your option) any later version.  The latest version
%% of this license is in the file
%%
%%    http://www.latex-project.org/lppl.txt
%%
%% This file is part of the "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 LaTeX3 Project.
%%
%% -----------------------------------------------------------------------
%
%<*driver|package>
\RequirePackage{l3names}
\GetIdInfo$Id: l3keyval.dtx 2478 2011-06-19 21:34:23Z joseph $
  {L3 Experimental key-value parsing}
%</driver|package>
%<*driver>
\documentclass[full]{l3doc}
\begin{document}
  \DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \title{^^A
%   The \pkg{l3keyval} package\\ Key--value parsing^^A
%   \thanks{This file describes v\ExplFileVersion,
%      last revised \ExplFileDate.}^^A
% }
%
% \author{^^A
%  The \LaTeX3 Project\thanks
%    {^^A
%      E-mail:
%        \href{mailto:latex-team@latex-project.org}
%          {latex-team@latex-project.org}^^A
%    }^^A
% }
%
% \date{Released \ExplFileDate}
%
% \maketitle
%
% \begin{documentation}
% 
% A key--value list is input of the form
% \begin{verbatim}
%   KeyOne = ValueOne ,
%   KeyTwo = ValueTwo ,
%   KeyThree   
% \end{verbatim} 
% where each key--value pair is separated by a comma from the rest of
% the list, and each key--value pair does not necessarily contain an
% equals sign or a value! Processing this type of input correctly 
% requires a number of careful steps, to correctly account for
% braces, spaces and the category codes of separators.
% 
% This module provides the low-level machinery for processing arbitrary
% key--value lists. The \pkg{l3keys} module provides a higher-level
% interface for managing run-time settings using key--value input,
% while other parts of \LaTeX3 also use key--value input based on
% \pkg{l3keyval} (for example the \pkg{xtemplate} module).
% 
 %\section{Parsing key--value lists}
%
% The low-level parsing system converts a \meta{key--value list}
% into \meta{keys} and associated \meta{values}. After the parsing phase
% is completed, the resulting keys and values (or keys alone) are
% available for further processing. This is not carried out by the
% low-level parser, and so the parser requires the names of
% two functions along with the key--value list. One function is
% needed to process key--value pairs (\emph{i.e}~two arguments), 
% and a second function if required for keys given without arguments
% (\emph{i.e.}~a single argument).
% 
% The parser does not double |#| tokens or expand any input. The tokens
% |=| and |,| are corrected so that the parser does not \enquote{miss}
% any due to category code changes. Spaces are removed from the ends
% of the keys and values. Values which are given in braces will have
% exactly one set removed, thus
% \begin{verbatim}
%    key = {value here},
% \end{verbatim}
% and
% \begin{verbatim}
%   key = value here,
% \end{verbatim}
% are treated identically.
% 
 %\begin{function}{\keyval_parse:NNn}
%   \begin{syntax}
%     \cs{keyval_parse:NNn} \meta{function1} \meta{function2}
%     ~~\Arg{key--value list}
%   \end{syntax}
%   Parses the \meta{key--value list} into a series of \meta{keys} and
%   associated \meta{values}, or keys alone (if no \meta{value} was
%   given).  \meta{function1} should take one argument, while
%   \meta{function2} should absorb two arguments. After
%   \cs{keyval_parse:NNn} has parsed the \meta{key--value list}, 
%   \meta{function1} will be used to process keys given with no value
%   and \meta{function2} will be used to process keys given with a
%   value. The order of the \meta{keys} in the \meta{key--value list}
%   will be preserved. Thus
%   \begin{verbatim}
%     \keyval_parse:NNn \function:n \function:nn
%       { key1 = value1 , key2 = value2, key3 = , key4 }
%   \end{verbatim}
%   will be converted into an input stream
%   \begin{verbatim}
%     \function:nn { key1 } { value1 }
%     \function:nn { key2 } { value2 }
%     \function:nn { key3 } { }
%     \function:n  { key4 }
%   \end{verbatim}
%   Note that there is a difference between an empty value (an equals
%   sign followed by nothing) and a missing value (no equals sign at
%   all). 
% \end{function}
%
% \end{documentation}
%
% \begin{implementation}
%
% \section{\pkg{l3keyval} implementation}
%
%    \begin{macrocode}
%<*initex|package>
%    \end{macrocode}
%    
%    \begin{macrocode}
%<*package>
\ProvidesExplPackage
  {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
\package_check_loaded_expl:
%</package>
%    \end{macrocode}
%    
% \begin{variable}{\g_keyval_level_int}
%   For nesting purposes an integer is needed for the current level.
%    \begin{macrocode}
\int_new:N \g_keyval_level_int
%    \end{macrocode}
% \end{variable}
%
% \begin{variable}{\l_keyval_key_tl, \l_keyval_value_tl}
%   The current key name and value.
%    \begin{macrocode}
\tl_new:N \l_keyval_key_tl
\tl_new:N \l_keyval_value_tl
%    \end{macrocode}
% \end{variable}
%
% \begin{variable}{\l_keyval_sanitise_tl}
% \begin{variable}{\l_keyval_parse_tl}
%   Token list variables for dealing with awkward category codes in the
%   input.
%    \begin{macrocode}
\tl_new:N \l_keyval_sanitise_tl
\tl_new:N \l_keyval_parse_tl
%    \end{macrocode}
%\end{variable}
%\end{variable}
%
% \begin{macro}{\keyval_parse:n}
%   The parsing function first deals with the category codes for
%   |=| and |,|, so that there are no odd events. The input is then
%   handed off to the element by element system. 
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_active:n { `\= }
  \char_set_catcode_active:n { `\, }
  \char_set_lccode:nn { `\8 } { `\= }
  \char_set_lccode:nn { `\9 } { `\, }
\tl_to_lowercase:n
  {
    \group_end:
    \cs_new_protected:Npn \keyval_parse:n #1
      {
        \group_begin:
          \tl_clear:N \l_keyval_sanitise_tl
          \tl_set:Nn \l_keyval_sanitise_tl {#1}
          \tl_replace_all_in:Nnn \l_keyval_sanitise_tl { = } { 8 }
          \tl_replace_all_in:Nnn \l_keyval_sanitise_tl { , } { 9 }
          \tl_clear:N \l_keyval_parse_tl
          \exp_after:wN \keyval_parse_elt:w \exp_after:wN
            \q_no_value \l_keyval_sanitise_tl 9 \q_nil 9
        \exp_after:wN \group_end:
        \l_keyval_parse_tl
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\keyval_parse_elt:w}
%   Each item to be parsed will have \cs{q_no_value} added to the front.
%   Hence the blank test here can always be used to find a totally
%   empty argument. If this is the case, the system loops round. If there
%   is something to parse, there is a check for the \cs{q_nil} marker
%   and if not a hand-off.
%    \begin{macrocode}
\cs_new_protected:Npn \keyval_parse_elt:w #1 ,
  {
    \tl_if_blank:oTF { \use_none:n #1 }
      { \keyval_parse_elt:w \q_no_value }
      {
        \quark_if_nil:oF { \use_ii:nn #1 }
          {
            \keyval_split_key_value:w #1 = = \q_stop
            \keyval_parse_elt:w \q_no_value
          }
      }
  }
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\keyval_split_key_value:w}
% \begin{macro}[aux]{\keyval_split_key_value_aux:wTF}
%   The key and value are handled separately. First the key is grabbed and
%   saved as \cs{l_keyval_key_tl}. Then a check is need to see if there is
%   a value at all: if not then the key name is simply added to the output.
%   If there is a value then there is a check to ensure that there was
%   only one |=| in the input (remembering some extra ones are around at
%   the moment to prevent errors). All being well, there is an
%   hand-off to find the value: the \cs{q_nil} is there to prevent loss
%   of braces.
%    \begin{macrocode}
\cs_new_protected:Npn \keyval_split_key_value:w #1 = #2 \q_stop
  {
    \keyval_split_key:w #1 \q_stop
    \str_if_eq:nnTF {#2} { = }
      {
        \tl_put_right:Nx \l_keyval_parse_tl
          {
            \exp_not:c { keyval_key_no_value_elt_ \int_use:N \g_keyval_level_int :n }
              { \exp_not:o \l_keyval_key_tl }
          }
      }
      {
        \keyval_split_key_value_aux:wTF #2 \q_no_value \q_stop
          { \keyval_split_value:w \q_nil #2 }
          { \msg_kernel_error:nn { keyval } { misplaced-equals-sign } }
      }
  }
\cs_new:Npn \keyval_split_key_value_aux:wTF #1 = #2#3 \q_stop
  { \tl_if_head_eq_meaning:nNTF {#3} \q_no_value }
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\keyval_split_key:w}
% \begin{macro}{\keyval_remove_spaces:w}
% \begin{macro}[aux]{\keyval_split_key_aux:w}
% \begin{macro}[aux]{\keyval_remove_spaces_aux:w}
%   The aim here is to remove spaces and also exactly one set of braces.
%   The spaces are trimmed off from each end using a \enquote{funny}
%   |Q|, which will never turn up in normal use. The idea is that
%   the \texttt{f}-type expansion will stop if it finds an unexpandable
%   token or a space, and will gobble the space. To avoid expanding
%   anything else, the \cs{exp_not:N} works by ensuring that the first
%   non-space token in the setting will stop the \texttt{f}-type
%   expansion. The \cs{use_none:n} is needed to remove the leading
%   quark, while the second setting of \cs{l_keyval_key_tl}
%   removes exactly one set of braces.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_math_toggle:n { `\Q }
  \cs_new_protected:Npn \keyval_split_key:w #1 \q_stop
    {
      \exp_args:NNf \tl_set:Nn \l_keyval_key_tl
        {
          \exp_after:wN \keyval_remove_spaces:w \exp_after:wN
            \exp_not:N \use_none:n #1 Q ~ Q
        }
      \tl_set:Nx \l_keyval_key_tl
        { \exp_after:wN \keyval_split_key_aux:w \l_keyval_key_tl \q_stop }
    }
  \cs_gset:Npn \keyval_split_key_aux:w #1 \q_stop { \exp_not:n {#1} }
  \cs_gset:Npn \keyval_remove_spaces:w #1 ~ Q { \keyval_remove_spaces_aux:w #1 Q }
  \cs_gset:Npn \keyval_remove_spaces_aux:w #1 Q #2 {#1}
\group_end:
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\keyval_split_value:w}
%   Here the value has to be separated from the equals signs and the
%   leading \cs{q_nil} added in to keep the brace levels. Fist the
%   processing function can be added to the output list. If there is no
%   value, setting \cs{l_keyval_value_tl} with three groups removed will
%   leave nothing at all, and so an empty group can be added to the
%   parsed list. On the other hand, if the value is entirely contained
%   within a set of braces then \cs{l_keyval_value_tl} will contain
%   \cs{q_nil} only. In that case, strip off the leading quark using
%   \cs{use_ii:nnn}, which also deals with any spaces.
%    \begin{macrocode}
\cs_new_protected:Npn \keyval_split_value:w #1 = =
  {
    \tl_put_right:Nx \l_keyval_parse_tl
      {
        \exp_not:c { keyval_key_value_elt_ \int_use:N \g_keyval_level_int :nn }
          { \exp_not:o \l_keyval_key_tl }
      }
    \tl_set:Nx \l_keyval_value_tl { \exp_not:o { \use_none:nnn #1 \q_nil \q_nil } }
    \tl_if_empty:NTF \l_keyval_value_tl
      { \tl_put_right:Nn \l_keyval_parse_tl { { } } }
      {
        \quark_if_nil:NTF \l_keyval_value_tl
          {
            \tl_put_right:Nx \l_keyval_parse_tl
              { { \exp_not:o { \use_ii:nnn #1 \q_nil } } }
          }
          { \keyval_split_value_aux:w #1 \q_stop }
      }
  }
%    \end{macrocode}
%   A similar idea to the key code: remove the spaces from each end and
%   deal with one set of braces.
%    \begin{macrocode}
\group_begin:
  \char_set_catcode_math_toggle:n { `\Q }
  \cs_new_protected:Npn \keyval_split_value_aux:w \q_nil #1 \q_stop
    {
      \exp_args:NNf \tl_set:Nn \l_keyval_value_tl
        { \keyval_remove_spaces:w \exp_not:N #1 Q ~ Q }
      \tl_put_right:Nx \l_keyval_parse_tl { { \exp_not:o \l_keyval_value_tl } }
    }
\group_end:
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\keyval_parse:NNn}
%   The outer parsing routine just sets up the processing functions and
%   hands off.
%    \begin{macrocode}
\cs_new_protected:Npn \keyval_parse:NNn #1#2#3
  {
    \int_gincr:N \g_keyval_level_int
    \cs_gset_eq:cN { keyval_key_no_value_elt_ \int_use:N \g_keyval_level_int :n } #1
    \cs_gset_eq:cN { keyval_key_value_elt_ \int_use:N \g_keyval_level_int :nn }   #2
    \keyval_parse:n {#3}
    \int_gdecr:N \g_keyval_level_int
  }
%    \end{macrocode}
% \end{macro}
%
% One message for the low level parsing system.
%    \begin{macrocode}
\msg_kernel_new:nnnn { keyval } { misplaced-equals-sign }
  { Misplaced~equals~sign~in~key-value~input~\msg_line_number: }
  {
    LaTeX~is~attempting~to~parse~some~key-value~input~but~found~
    two~equals~signs~not~separated~by~a~comma.
  }
%    \end{macrocode}
%    
% \subsection{Deprecated functions}
% 
% Deprecated on 2011-05-27, for removal by 2011-08-31.
%
% \begin{macro}{\KV_process_space_removal_sanitize:NNn}
% \begin{macro}{\KV_process_space_removal_no_sanitize:NNn}
% \begin{macro}{\KV_process_no_space_removal_no_sanitize:NNn}
% There is just one function for this now.
%    \begin{macrocode}
\cs_new_eq:NN \KV_process_space_removal_sanitize:NNn       \keyval_parse:NNn
\cs_new_eq:NN \KV_process_space_removal_no_sanitize:NNn    \keyval_parse:NNn
\cs_new_eq:NN \KV_process_no_space_removal_no_sanitize:NNn \keyval_parse:NNn
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%    \begin{macrocode}
%</initex|package>
%    \end{macrocode}
% 
% \end{implementation}
% 
% \PrintIndex