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1 divert(-1)# -*- Autoconf -*-
2 # This file is part of Autoconf.
3 # Base M4 layer.
4 # Requires GNU M4.
5 #
6 # Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software
7 # Foundation, Inc.
8 #
9 # This program is free software; you can redistribute it and/or modify
10 # it under the terms of the GNU General Public License as published by
11 # the Free Software Foundation; either version 2, or (at your option)
12 # any later version.
13 #
14 # This program is distributed in the hope that it will be useful,
15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 # GNU General Public License for more details.
18 #
19 # You should have received a copy of the GNU General Public License
20 # along with this program; if not, write to the Free Software
21 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 # 02110-1301, USA.
23 #
24 # As a special exception, the Free Software Foundation gives unlimited
25 # permission to copy, distribute and modify the configure scripts that
26 # are the output of Autoconf. You need not follow the terms of the GNU
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30 # that constitutes the Autoconf program.
31 #
32 # Certain portions of the Autoconf source text are designed to be copied
33 # (in certain cases, depending on the input) into the output of
34 # Autoconf. We call these the "data" portions. The rest of the Autoconf
35 # source text consists of comments plus executable code that decides which
36 # of the data portions to output in any given case. We call these
37 # comments and executable code the "non-data" portions. Autoconf never
38 # copies any of the non-data portions into its output.
39 #
40 # This special exception to the GPL applies to versions of Autoconf
41 # released by the Free Software Foundation. When you make and
42 # distribute a modified version of Autoconf, you may extend this special
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44 # your modified version has the potential to copy into its output some
45 # of the text that was the non-data portion of the version that you started
46 # with. (In other words, unless your change moves or copies text from
47 # the non-data portions to the data portions.) If your modification has
48 # such potential, you must delete any notice of this special exception
49 # to the GPL from your modified version.
50 #
51 # Written by Akim Demaille.
52 #
53
54 # Set the quotes, whatever the current quoting system.
55 changequote()
56 changequote([, ])
57
58 # Some old m4's don't support m4exit. But they provide
59 # equivalent functionality by core dumping because of the
60 # long macros we define.
61 ifdef([__gnu__], ,
62 [errprint(M4sugar requires GNU M4. Install it before installing M4sugar or
63 set the M4 environment variable to its absolute file name.)
64 m4exit(2)])
65
66
67 ## ------------------------------- ##
68 ## 1. Simulate --prefix-builtins. ##
69 ## ------------------------------- ##
70
71 # m4_define
72 # m4_defn
73 # m4_undefine
74 define([m4_define], defn([define]))
75 define([m4_defn], defn([defn]))
76 define([m4_undefine], defn([undefine]))
77
78 m4_undefine([define])
79 m4_undefine([defn])
80 m4_undefine([undefine])
81
82
83 # m4_copy(SRC, DST)
84 # -----------------
85 # Define DST as the definition of SRC.
86 # What's the difference between:
87 # 1. m4_copy([from], [to])
88 # 2. m4_define([to], [from($@)])
89 # Well, obviously 1 is more expensive in space. Maybe 2 is more expensive
90 # in time, but because of the space cost of 1, it's not that obvious.
91 # Nevertheless, one huge difference is the handling of `$0'. If `from'
92 # uses `$0', then with 1, `to''s `$0' is `to', while it is `from' in 2.
93 # The user will certainly prefer to see `to'.
94 m4_define([m4_copy],
95 [m4_define([$2], m4_defn([$1]))])
96
97
98 # m4_rename(SRC, DST)
99 # -------------------
100 # Rename the macro SRC as DST.
101 m4_define([m4_rename],
102 [m4_copy([$1], [$2])m4_undefine([$1])])
103
104
105 # m4_rename_m4(MACRO-NAME)
106 # ------------------------
107 # Rename MACRO-NAME as m4_MACRO-NAME.
108 m4_define([m4_rename_m4],
109 [m4_rename([$1], [m4_$1])])
110
111
112 # m4_copy_unm4(m4_MACRO-NAME)
113 # ---------------------------
114 # Copy m4_MACRO-NAME as MACRO-NAME.
115 m4_define([m4_copy_unm4],
116 [m4_copy([$1], m4_bpatsubst([$1], [^m4_\(.*\)], [[\1]]))])
117
118
119 # Some m4 internals have names colliding with tokens we might use.
120 # Rename them a` la `m4 --prefix-builtins'.
121 m4_rename_m4([builtin])
122 m4_rename_m4([changecom])
123 m4_rename_m4([changequote])
124 m4_rename_m4([debugfile])
125 m4_rename_m4([debugmode])
126 m4_rename_m4([decr])
127 m4_undefine([divert])
128 m4_rename_m4([divnum])
129 m4_rename_m4([dumpdef])
130 m4_rename_m4([errprint])
131 m4_rename_m4([esyscmd])
132 m4_rename_m4([eval])
133 m4_rename_m4([format])
134 m4_rename_m4([ifdef])
135 m4_rename([ifelse], [m4_if])
136 m4_undefine([include])
137 m4_rename_m4([incr])
138 m4_rename_m4([index])
139 m4_rename_m4([indir])
140 m4_rename_m4([len])
141 m4_rename([m4exit], [m4_exit])
142 m4_rename([m4wrap], [m4_wrap])
143 m4_rename_m4([maketemp])
144 m4_rename([patsubst], [m4_bpatsubst])
145 m4_undefine([popdef])
146 m4_rename_m4([pushdef])
147 m4_rename([regexp], [m4_bregexp])
148 m4_rename_m4([shift])
149 m4_undefine([sinclude])
150 m4_rename_m4([substr])
151 m4_rename_m4([symbols])
152 m4_rename_m4([syscmd])
153 m4_rename_m4([sysval])
154 m4_rename_m4([traceoff])
155 m4_rename_m4([traceon])
156 m4_rename_m4([translit])
157 m4_undefine([undivert])
158
159
160 ## ------------------- ##
161 ## 2. Error messages. ##
162 ## ------------------- ##
163
164
165 # m4_location
166 # -----------
167 m4_define([m4_location],
168 [__file__:__line__])
169
170
171 # m4_errprintn(MSG)
172 # -----------------
173 # Same as `errprint', but with the missing end of line.
174 m4_define([m4_errprintn],
175 [m4_errprint([$1
176 ])])
177
178
179 # m4_warning(MSG)
180 # ---------------
181 # Warn the user.
182 m4_define([m4_warning],
183 [m4_errprintn(m4_location[: warning: $1])])
184
185
186 # m4_fatal(MSG, [EXIT-STATUS])
187 # ----------------------------
188 # Fatal the user. :)
189 m4_define([m4_fatal],
190 [m4_errprintn(m4_location[: error: $1])dnl
191 m4_expansion_stack_dump()dnl
192 m4_exit(m4_if([$2],, 1, [$2]))])
193
194
195 # m4_assert(EXPRESSION, [EXIT-STATUS = 1])
196 # ----------------------------------------
197 # This macro ensures that EXPRESSION evaluates to true, and exits if
198 # EXPRESSION evaluates to false.
199 m4_define([m4_assert],
200 [m4_if(m4_eval([$1]), 0,
201 [m4_fatal([assert failed: $1], [$2])])])
202
203
204
205 ## ------------- ##
206 ## 3. Warnings. ##
207 ## ------------- ##
208
209
210 # _m4_warn(CATEGORY, MESSAGE, STACK-TRACE)
211 # ----------------------------------------
212 # Report a MESSAGE to the user if the CATEGORY of warnings is enabled.
213 # This is for traces only.
214 # The STACK-TRACE is a \n-separated list of "LOCATION: MESSAGE".
215 m4_define([_m4_warn], [])
216
217
218 # m4_warn(CATEGORY, MESSAGE)
219 # --------------------------
220 # Report a MESSAGE to the user if the CATEGORY of warnings is enabled.
221 m4_define([m4_warn],
222 [_m4_warn([$1], [$2],
223 m4_ifdef([m4_expansion_stack],
224 [m4_defn([m4_expansion_stack])
225 m4_location[: the top level]]))dnl
226 ])
227
228
229
230 ## ------------------- ##
231 ## 4. File inclusion. ##
232 ## ------------------- ##
233
234
235 # We also want to neutralize include (and sinclude for symmetry),
236 # but we want to extend them slightly: warn when a file is included
237 # several times. This is in general a dangerous operation because
238 # quite nobody quotes the first argument of m4_define.
239 #
240 # For instance in the following case:
241 # m4_define(foo, [bar])
242 # then a second reading will turn into
243 # m4_define(bar, [bar])
244 # which is certainly not what was meant.
245
246 # m4_include_unique(FILE)
247 # -----------------------
248 # Declare that the FILE was loading; and warn if it has already
249 # been included.
250 m4_define([m4_include_unique],
251 [m4_ifdef([m4_include($1)],
252 [m4_warn([syntax], [file `$1' included several times])])dnl
253 m4_define([m4_include($1)])])
254
255
256 # m4_include(FILE)
257 # ----------------
258 # As the builtin include, but warns against multiple inclusions.
259 m4_define([m4_include],
260 [m4_include_unique([$1])dnl
261 m4_builtin([include], [$1])])
262
263
264 # m4_sinclude(FILE)
265 # -----------------
266 # As the builtin sinclude, but warns against multiple inclusions.
267 m4_define([m4_sinclude],
268 [m4_include_unique([$1])dnl
269 m4_builtin([sinclude], [$1])])
270
271
272
273 ## ------------------------------------ ##
274 ## 5. Additional branching constructs. ##
275 ## ------------------------------------ ##
276
277 # Both `m4_ifval' and `m4_ifset' tests against the empty string. The
278 # difference is that `m4_ifset' is specialized on macros.
279 #
280 # In case of arguments of macros, eg $[1], it makes little difference.
281 # In the case of a macro `FOO', you don't want to check `m4_ifval(FOO,
282 # TRUE)', because if `FOO' expands with commas, there is a shifting of
283 # the arguments. So you want to run `m4_ifval([FOO])', but then you just
284 # compare the *string* `FOO' against `', which, of course fails.
285 #
286 # So you want a variation of `m4_ifset' that expects a macro name as $[1].
287 # If this macro is both defined and defined to a non empty value, then
288 # it runs TRUE etc.
289
290
291 # m4_ifval(COND, [IF-TRUE], [IF-FALSE])
292 # -------------------------------------
293 # If COND is not the empty string, expand IF-TRUE, otherwise IF-FALSE.
294 # Comparable to m4_ifdef.
295 m4_define([m4_ifval],
296 [m4_if([$1], [], [$3], [$2])])
297
298
299 # m4_n(TEXT)
300 # ----------
301 # If TEXT is not empty, return TEXT and a new line, otherwise nothing.
302 m4_define([m4_n],
303 [m4_if([$1],
304 [], [],
305 [$1
306 ])])
307
308
309 # m4_ifvaln(COND, [IF-TRUE], [IF-FALSE])
310 # --------------------------------------
311 # Same as `m4_ifval', but add an extra newline to IF-TRUE or IF-FALSE
312 # unless that argument is empty.
313 m4_define([m4_ifvaln],
314 [m4_if([$1],
315 [], [m4_n([$3])],
316 [m4_n([$2])])])
317
318
319 # m4_ifset(MACRO, [IF-TRUE], [IF-FALSE])
320 # --------------------------------------
321 # If MACRO has no definition, or of its definition is the empty string,
322 # expand IF-FALSE, otherwise IF-TRUE.
323 m4_define([m4_ifset],
324 [m4_ifdef([$1],
325 [m4_ifval(m4_defn([$1]), [$2], [$3])],
326 [$3])])
327
328
329 # m4_ifndef(NAME, [IF-NOT-DEFINED], [IF-DEFINED])
330 # -----------------------------------------------
331 m4_define([m4_ifndef],
332 [m4_ifdef([$1], [$3], [$2])])
333
334
335 # m4_case(SWITCH, VAL1, IF-VAL1, VAL2, IF-VAL2, ..., DEFAULT)
336 # -----------------------------------------------------------
337 # m4 equivalent of
338 # switch (SWITCH)
339 # {
340 # case VAL1:
341 # IF-VAL1;
342 # break;
343 # case VAL2:
344 # IF-VAL2;
345 # break;
346 # ...
347 # default:
348 # DEFAULT;
349 # break;
350 # }.
351 # All the values are optional, and the macro is robust to active
352 # symbols properly quoted.
353 m4_define([m4_case],
354 [m4_if([$#], 0, [],
355 [$#], 1, [],
356 [$#], 2, [$2],
357 [$1], [$2], [$3],
358 [$0([$1], m4_shiftn(3, $@))])])
359
360
361 # m4_bmatch(SWITCH, RE1, VAL1, RE2, VAL2, ..., DEFAULT)
362 # -----------------------------------------------------
363 # m4 equivalent of
364 #
365 # if (SWITCH =~ RE1)
366 # VAL1;
367 # elif (SWITCH =~ RE2)
368 # VAL2;
369 # elif ...
370 # ...
371 # else
372 # DEFAULT
373 #
374 # All the values are optional, and the macro is robust to active symbols
375 # properly quoted.
376 m4_define([m4_bmatch],
377 [m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])],
378 [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])],
379 [$#], 2, [$2],
380 [m4_if(m4_bregexp([$1], [$2]), -1, [$0([$1], m4_shiftn(3, $@))],
381 [$3])])])
382
383
384 # m4_car(LIST)
385 # m4_cdr(LIST)
386 # ------------
387 # Manipulate m4 lists.
388 m4_define([m4_car], [[$1]])
389 m4_define([m4_cdr],
390 [m4_if([$#], 0, [m4_fatal([$0: cannot be called without arguments])],
391 [$#], 1, [],
392 [m4_dquote(m4_shift($@))])])
393
394
395 # m4_map(MACRO, LIST)
396 # -------------------
397 # Invoke MACRO($1), MACRO($2) etc. where $1, $2... are the elements
398 # of LIST (which can be lists themselves, for multiple arguments MACROs).
399 m4_define([m4_fst], [$1])
400 m4_define([m4_map],
401 [m4_if([$2], [[]], [],
402 [_m4_map([$1], [$2])])])
403 m4_define([_m4_map],
404 [m4_ifval([$2],
405 [$1(m4_fst($2))[]_m4_map([$1], m4_cdr($2))])])
406
407
408 # m4_map_sep(MACRO, SEPARATOR, LIST)
409 # ----------------------------------
410 # Invoke MACRO($1), SEPARATOR, MACRO($2), ..., MACRO($N) where $1, $2... $N
411 # are the elements of LIST (which can be lists themselves, for multiple
412 # arguments MACROs).
413 m4_define([m4_map_sep],
414 [m4_if([$3], [[]], [],
415 [$1(m4_fst($3))[]_m4_map([$2[]$1], m4_cdr($3))])])
416
417
418 ## ---------------------------------------- ##
419 ## 6. Enhanced version of some primitives. ##
420 ## ---------------------------------------- ##
421
422 # m4_bpatsubsts(STRING, RE1, SUBST1, RE2, SUBST2, ...)
423 # ----------------------------------------------------
424 # m4 equivalent of
425 #
426 # $_ = STRING;
427 # s/RE1/SUBST1/g;
428 # s/RE2/SUBST2/g;
429 # ...
430 #
431 # All the values are optional, and the macro is robust to active symbols
432 # properly quoted.
433 #
434 # I would have liked to name this macro `m4_bpatsubst', unfortunately,
435 # due to quotation problems, I need to double quote $1 below, therefore
436 # the anchors are broken :( I can't let users be trapped by that.
437 m4_define([m4_bpatsubsts],
438 [m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])],
439 [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])],
440 [$#], 2, [m4_builtin([patsubst], $@)],
441 [$0(m4_builtin([patsubst], [[$1]], [$2], [$3]),
442 m4_shiftn(3, $@))])])
443
444
445
446 # m4_do(STRING, ...)
447 # ------------------
448 # This macro invokes all its arguments (in sequence, of course). It is
449 # useful for making your macros more structured and readable by dropping
450 # unnecessary dnl's and have the macros indented properly.
451 m4_define([m4_do],
452 [m4_if($#, 0, [],
453 $#, 1, [$1],
454 [$1[]m4_do(m4_shift($@))])])
455
456
457 # m4_define_default(MACRO, VALUE)
458 # -------------------------------
459 # If MACRO is undefined, set it to VALUE.
460 m4_define([m4_define_default],
461 [m4_ifndef([$1], [m4_define($@)])])
462
463
464 # m4_default(EXP1, EXP2)
465 # ----------------------
466 # Returns EXP1 if non empty, otherwise EXP2.
467 m4_define([m4_default],
468 [m4_ifval([$1], [$1], [$2])])
469
470
471 # m4_defn(NAME)
472 # -------------
473 # Unlike to the original, don't tolerate popping something which is
474 # undefined.
475 m4_define([m4_defn],
476 [m4_ifndef([$1],
477 [m4_fatal([$0: undefined macro: $1])])dnl
478 m4_builtin([defn], $@)])
479
480
481 # _m4_dumpdefs_up(NAME)
482 # ---------------------
483 m4_define([_m4_dumpdefs_up],
484 [m4_ifdef([$1],
485 [m4_pushdef([_m4_dumpdefs], m4_defn([$1]))dnl
486 m4_dumpdef([$1])dnl
487 m4_popdef([$1])dnl
488 _m4_dumpdefs_up([$1])])])
489
490
491 # _m4_dumpdefs_down(NAME)
492 # -----------------------
493 m4_define([_m4_dumpdefs_down],
494 [m4_ifdef([_m4_dumpdefs],
495 [m4_pushdef([$1], m4_defn([_m4_dumpdefs]))dnl
496 m4_popdef([_m4_dumpdefs])dnl
497 _m4_dumpdefs_down([$1])])])
498
499
500 # m4_dumpdefs(NAME)
501 # -----------------
502 # Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its
503 # value stack (most recent displayed first).
504 m4_define([m4_dumpdefs],
505 [_m4_dumpdefs_up([$1])dnl
506 _m4_dumpdefs_down([$1])])
507
508
509 # m4_popdef(NAME)
510 # ---------------
511 # Unlike to the original, don't tolerate popping something which is
512 # undefined.
513 m4_define([m4_popdef],
514 [m4_ifndef([$1],
515 [m4_fatal([$0: undefined macro: $1])])dnl
516 m4_builtin([popdef], $@)])
517
518
519 # m4_quote(ARGS)
520 # --------------
521 # Return ARGS as a single arguments.
522 #
523 # It is important to realize the difference between `m4_quote(exp)' and
524 # `[exp]': in the first case you obtain the quoted *result* of the
525 # expansion of EXP, while in the latter you just obtain the string
526 # `exp'.
527 m4_define([m4_quote], [[$*]])
528 m4_define([m4_dquote], [[$@]])
529
530
531 # m4_noquote(STRING)
532 # ------------------
533 # Return the result of ignoring all quotes in STRING and invoking the
534 # macros it contains. Amongst other things useful for enabling macro
535 # invocations inside strings with [] blocks (for instance regexps and
536 # help-strings).
537 m4_define([m4_noquote],
538 [m4_changequote(-=<{,}>=-)$1-=<{}>=-m4_changequote([,])])
539
540
541 # m4_shiftn(N, ...)
542 # -----------------
543 # Returns ... shifted N times. Useful for recursive "varargs" constructs.
544 m4_define([m4_shiftn],
545 [m4_assert(($1 >= 0) && ($# > $1))dnl
546 _m4_shiftn($@)])
547
548 m4_define([_m4_shiftn],
549 [m4_if([$1], 0,
550 [m4_shift($@)],
551 [_m4_shiftn(m4_eval([$1]-1), m4_shift(m4_shift($@)))])])
552
553
554 # m4_undefine(NAME)
555 # -----------------
556 # Unlike to the original, don't tolerate undefining something which is
557 # undefined.
558 m4_define([m4_undefine],
559 [m4_ifndef([$1],
560 [m4_fatal([$0: undefined macro: $1])])dnl
561 m4_builtin([undefine], $@)])
562
563
564 ## -------------------------- ##
565 ## 7. Implementing m4 loops. ##
566 ## -------------------------- ##
567
568
569 # m4_for(VARIABLE, FIRST, LAST, [STEP = +/-1], EXPRESSION)
570 # --------------------------------------------------------
571 # Expand EXPRESSION defining VARIABLE to FROM, FROM + 1, ..., TO.
572 # Both limits are included, and bounds are checked for consistency.
573 m4_define([m4_for],
574 [m4_case(m4_sign(m4_eval($3 - $2)),
575 1, [m4_assert(m4_sign(m4_default($4, 1)) == 1)],
576 -1, [m4_assert(m4_sign(m4_default($4, -1)) == -1)])dnl
577 m4_pushdef([$1], [$2])dnl
578 m4_if(m4_eval([$3 > $2]), 1,
579 [_m4_for([$1], [$3], m4_default([$4], 1), [$5])],
580 [_m4_for([$1], [$3], m4_default([$4], -1), [$5])])dnl
581 m4_popdef([$1])])
582
583
584 # _m4_for(VARIABLE, FIRST, LAST, STEP, EXPRESSION)
585 # ------------------------------------------------
586 # Core of the loop, no consistency checks.
587 m4_define([_m4_for],
588 [$4[]dnl
589 m4_if($1, [$2], [],
590 [m4_define([$1], m4_eval($1+[$3]))_m4_for([$1], [$2], [$3], [$4])])])
591
592
593 # Implementing `foreach' loops in m4 is much more tricky than it may
594 # seem. Actually, the example of a `foreach' loop in the m4
595 # documentation is wrong: it does not quote the arguments properly,
596 # which leads to undesirable expansions.
597 #
598 # The example in the documentation is:
599 #
600 # | # foreach(VAR, (LIST), STMT)
601 # | m4_define([foreach],
602 # | [m4_pushdef([$1])_foreach([$1], [$2], [$3])m4_popdef([$1])])
603 # | m4_define([_arg1], [$1])
604 # | m4_define([_foreach],
605 # | [m4_if([$2], [()], ,
606 # | [m4_define([$1], _arg1$2)$3[]_foreach([$1],
607 # | (shift$2),
608 # | [$3])])])
609 #
610 # But then if you run
611 #
612 # | m4_define(a, 1)
613 # | m4_define(b, 2)
614 # | m4_define(c, 3)
615 # | foreach([f], [([a], [(b], [c)])], [echo f
616 # | ])
617 #
618 # it gives
619 #
620 # => echo 1
621 # => echo (2,3)
622 #
623 # which is not what is expected.
624 #
625 # Of course the problem is that many quotes are missing. So you add
626 # plenty of quotes at random places, until you reach the expected
627 # result. Alternatively, if you are a quoting wizard, you directly
628 # reach the following implementation (but if you really did, then
629 # apply to the maintenance of m4sugar!).
630 #
631 # | # foreach(VAR, (LIST), STMT)
632 # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])])
633 # | m4_define([_arg1], [[$1]])
634 # | m4_define([_foreach],
635 # | [m4_if($2, [()], ,
636 # | [m4_define([$1], [_arg1$2])$3[]_foreach([$1],
637 # | [(shift$2)],
638 # | [$3])])])
639 #
640 # which this time answers
641 #
642 # => echo a
643 # => echo (b
644 # => echo c)
645 #
646 # Bingo!
647 #
648 # Well, not quite.
649 #
650 # With a better look, you realize that the parens are more a pain than
651 # a help: since anyway you need to quote properly the list, you end up
652 # with always using an outermost pair of parens and an outermost pair
653 # of quotes. Rejecting the parens both eases the implementation, and
654 # simplifies the use:
655 #
656 # | # foreach(VAR, (LIST), STMT)
657 # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])])
658 # | m4_define([_arg1], [$1])
659 # | m4_define([_foreach],
660 # | [m4_if($2, [], ,
661 # | [m4_define([$1], [_arg1($2)])$3[]_foreach([$1],
662 # | [shift($2)],
663 # | [$3])])])
664 #
665 #
666 # Now, just replace the `$2' with `m4_quote($2)' in the outer `m4_if'
667 # to improve robustness, and you come up with a quite satisfactory
668 # implementation.
669
670
671 # m4_foreach(VARIABLE, LIST, EXPRESSION)
672 # --------------------------------------
673 #
674 # Expand EXPRESSION assigning each value of the LIST to VARIABLE.
675 # LIST should have the form `item_1, item_2, ..., item_n', i.e. the
676 # whole list must *quoted*. Quote members too if you don't want them
677 # to be expanded.
678 #
679 # This macro is robust to active symbols:
680 # | m4_define(active, [ACT, IVE])
681 # | m4_foreach(Var, [active, active], [-Var-])
682 # => -ACT--IVE--ACT--IVE-
683 #
684 # | m4_foreach(Var, [[active], [active]], [-Var-])
685 # => -ACT, IVE--ACT, IVE-
686 #
687 # | m4_foreach(Var, [[[active]], [[active]]], [-Var-])
688 # => -active--active-
689 m4_define([m4_foreach],
690 [m4_pushdef([$1])_m4_foreach($@)m4_popdef([$1])])
691
692 m4_define([_m4_foreach],
693 [m4_ifval([$2],
694 [m4_define([$1], m4_car($2))$3[]dnl
695 _m4_foreach([$1], m4_cdr($2), [$3])])])
696
697
698 # m4_foreach_w(VARIABLE, LIST, EXPRESSION)
699 # ----------------------------------------
700 #
701 # Like m4_foreach, but the list is whitespace separated.
702 #
703 # This macro is robust to active symbols:
704 # m4_foreach_w([Var], [ active
705 # b act\
706 # ive ], [-Var-])end
707 # => -active--b--active-end
708 #
709 m4_define([m4_foreach_w],
710 [m4_foreach([$1], m4_split(m4_normalize([$2])), [$3])])
711
712
713
714 ## --------------------------- ##
715 ## 8. More diversion support. ##
716 ## --------------------------- ##
717
718
719 # _m4_divert(DIVERSION-NAME or NUMBER)
720 # ------------------------------------
721 # If DIVERSION-NAME is the name of a diversion, return its number,
722 # otherwise if it is a NUMBER return it.
723 m4_define([_m4_divert],
724 [m4_ifdef([_m4_divert($1)],
725 [m4_indir([_m4_divert($1)])],
726 [$1])])
727
728 # KILL is only used to suppress output.
729 m4_define([_m4_divert(KILL)], -1)
730
731
732 # _m4_divert_n_stack
733 # ------------------
734 # Print m4_divert_stack with newline prepended, if it's nonempty.
735 m4_define([_m4_divert_n_stack],
736 [m4_ifdef([m4_divert_stack], [
737 m4_defn([m4_divert_stack])])])
738
739
740 # m4_divert(DIVERSION-NAME)
741 # -------------------------
742 # Change the diversion stream to DIVERSION-NAME.
743 m4_define([m4_divert],
744 [m4_define([m4_divert_stack], m4_location[: $0: $1]_m4_divert_n_stack)dnl
745 m4_builtin([divert], _m4_divert([$1]))dnl
746 ])
747
748
749 # m4_divert_push(DIVERSION-NAME)
750 # ------------------------------
751 # Change the diversion stream to DIVERSION-NAME, while stacking old values.
752 m4_define([m4_divert_push],
753 [m4_pushdef([m4_divert_stack], m4_location[: $0: $1]_m4_divert_n_stack)dnl
754 m4_pushdef([_m4_divert_diversion], [$1])dnl
755 m4_builtin([divert], _m4_divert([$1]))dnl
756 ])
757
758
759 # m4_divert_pop([DIVERSION-NAME])
760 # -------------------------------
761 # Change the diversion stream to its previous value, unstacking it.
762 # If specified, verify we left DIVERSION-NAME.
763 # When we pop the last value from the stack, we divert to -1.
764 m4_define([m4_divert_pop],
765 [m4_ifndef([_m4_divert_diversion],
766 [m4_fatal([too many m4_divert_pop])])dnl
767 m4_if([$1], [], [],
768 [$1], m4_defn([_m4_divert_diversion]), [],
769 [m4_fatal([$0($1): diversion mismatch: ]_m4_divert_n_stack)])dnl
770 m4_popdef([m4_divert_stack])dnl
771 m4_popdef([_m4_divert_diversion])dnl
772 m4_builtin([divert],
773 m4_ifdef([_m4_divert_diversion],
774 [_m4_divert(m4_defn([_m4_divert_diversion]))],
775 -1))dnl
776 ])
777
778
779 # m4_divert_text(DIVERSION-NAME, CONTENT)
780 # ---------------------------------------
781 # Output CONTENT into DIVERSION-NAME (which may be a number actually).
782 # An end of line is appended for free to CONTENT.
783 m4_define([m4_divert_text],
784 [m4_divert_push([$1])dnl
785 $2
786 m4_divert_pop([$1])dnl
787 ])
788
789
790 # m4_divert_once(DIVERSION-NAME, CONTENT)
791 # ---------------------------------------
792 # Output once CONTENT into DIVERSION-NAME (which may be a number
793 # actually). An end of line is appended for free to CONTENT.
794 m4_define([m4_divert_once],
795 [m4_expand_once([m4_divert_text([$1], [$2])])])
796
797
798 # m4_undivert(DIVERSION-NAME)
799 # ---------------------------
800 # Undivert DIVERSION-NAME.
801 m4_define([m4_undivert],
802 [m4_builtin([undivert], _m4_divert([$1]))])
803
804
805 ## -------------------------------------------- ##
806 ## 8. Defining macros with bells and whistles. ##
807 ## -------------------------------------------- ##
808
809 # `m4_defun' is basically `m4_define' but it equips the macro with the
810 # needed machinery for `m4_require'. A macro must be m4_defun'd if
811 # either it is m4_require'd, or it m4_require's.
812 #
813 # Two things deserve attention and are detailed below:
814 # 1. Implementation of m4_require
815 # 2. Keeping track of the expansion stack
816 #
817 # 1. Implementation of m4_require
818 # ===============================
819 #
820 # Of course m4_defun AC_PROVIDE's the macro, so that a macro which has
821 # been expanded is not expanded again when m4_require'd, but the
822 # difficult part is the proper expansion of macros when they are
823 # m4_require'd.
824 #
825 # The implementation is based on two ideas, (i) using diversions to
826 # prepare the expansion of the macro and its dependencies (by Franc,ois
827 # Pinard), and (ii) expand the most recently m4_require'd macros _after_
828 # the previous macros (by Axel Thimm).
829 #
830 #
831 # The first idea: why using diversions?
832 # -------------------------------------
833 #
834 # When a macro requires another, the other macro is expanded in new
835 # diversion, GROW. When the outer macro is fully expanded, we first
836 # undivert the most nested diversions (GROW - 1...), and finally
837 # undivert GROW. To understand why we need several diversions,
838 # consider the following example:
839 #
840 # | m4_defun([TEST1], [Test...REQUIRE([TEST2])1])
841 # | m4_defun([TEST2], [Test...REQUIRE([TEST3])2])
842 # | m4_defun([TEST3], [Test...3])
843 #
844 # Because m4_require is not required to be first in the outer macros, we
845 # must keep the expansions of the various level of m4_require separated.
846 # Right before executing the epilogue of TEST1, we have:
847 #
848 # GROW - 2: Test...3
849 # GROW - 1: Test...2
850 # GROW: Test...1
851 # BODY:
852 #
853 # Finally the epilogue of TEST1 undiverts GROW - 2, GROW - 1, and
854 # GROW into the regular flow, BODY.
855 #
856 # GROW - 2:
857 # GROW - 1:
858 # GROW:
859 # BODY: Test...3; Test...2; Test...1
860 #
861 # (The semicolons are here for clarification, but of course are not
862 # emitted.) This is what Autoconf 2.0 (I think) to 2.13 (I'm sure)
863 # implement.
864 #
865 #
866 # The second idea: first required first out
867 # -----------------------------------------
868 #
869 # The natural implementation of the idea above is buggy and produces
870 # very surprising results in some situations. Let's consider the
871 # following example to explain the bug:
872 #
873 # | m4_defun([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])])
874 # | m4_defun([TEST2a], [])
875 # | m4_defun([TEST2b], [REQUIRE([TEST3])])
876 # | m4_defun([TEST3], [REQUIRE([TEST2a])])
877 # |
878 # | AC_INIT
879 # | TEST1
880 #
881 # The dependencies between the macros are:
882 #
883 # 3 --- 2b
884 # / \ is m4_require'd by
885 # / \ left -------------------- right
886 # 2a ------------ 1
887 #
888 # If you strictly apply the rules given in the previous section you get:
889 #
890 # GROW - 2: TEST3
891 # GROW - 1: TEST2a; TEST2b
892 # GROW: TEST1
893 # BODY:
894 #
895 # (TEST2a, although required by TEST3 is not expanded in GROW - 3
896 # because is has already been expanded before in GROW - 1, so it has
897 # been AC_PROVIDE'd, so it is not expanded again) so when you undivert
898 # the stack of diversions, you get:
899 #
900 # GROW - 2:
901 # GROW - 1:
902 # GROW:
903 # BODY: TEST3; TEST2a; TEST2b; TEST1
904 #
905 # i.e., TEST2a is expanded after TEST3 although the latter required the
906 # former.
907 #
908 # Starting from 2.50, uses an implementation provided by Axel Thimm.
909 # The idea is simple: the order in which macros are emitted must be the
910 # same as the one in which macro are expanded. (The bug above can
911 # indeed be described as: a macro has been AC_PROVIDE'd, but it is
912 # emitted after: the lack of correlation between emission and expansion
913 # order is guilty).
914 #
915 # How to do that? You keeping the stack of diversions to elaborate the
916 # macros, but each time a macro is fully expanded, emit it immediately.
917 #
918 # In the example above, when TEST2a is expanded, but it's epilogue is
919 # not run yet, you have:
920 #
921 # GROW - 2:
922 # GROW - 1: TEST2a
923 # GROW: Elaboration of TEST1
924 # BODY:
925 #
926 # The epilogue of TEST2a emits it immediately:
927 #
928 # GROW - 2:
929 # GROW - 1:
930 # GROW: Elaboration of TEST1
931 # BODY: TEST2a
932 #
933 # TEST2b then requires TEST3, so right before the epilogue of TEST3, you
934 # have:
935 #
936 # GROW - 2: TEST3
937 # GROW - 1: Elaboration of TEST2b
938 # GROW: Elaboration of TEST1
939 # BODY: TEST2a
940 #
941 # The epilogue of TEST3 emits it:
942 #
943 # GROW - 2:
944 # GROW - 1: Elaboration of TEST2b
945 # GROW: Elaboration of TEST1
946 # BODY: TEST2a; TEST3
947 #
948 # TEST2b is now completely expanded, and emitted:
949 #
950 # GROW - 2:
951 # GROW - 1:
952 # GROW: Elaboration of TEST1
953 # BODY: TEST2a; TEST3; TEST2b
954 #
955 # and finally, TEST1 is finished and emitted:
956 #
957 # GROW - 2:
958 # GROW - 1:
959 # GROW:
960 # BODY: TEST2a; TEST3; TEST2b: TEST1
961 #
962 # The idea is simple, but the implementation is a bit evolved. If you
963 # are like me, you will want to see the actual functioning of this
964 # implementation to be convinced. The next section gives the full
965 # details.
966 #
967 #
968 # The Axel Thimm implementation at work
969 # -------------------------------------
970 #
971 # We consider the macros above, and this configure.ac:
972 #
973 # AC_INIT
974 # TEST1
975 #
976 # You should keep the definitions of _m4_defun_pro, _m4_defun_epi, and
977 # m4_require at hand to follow the steps.
978 #
979 # This implements tries not to assume that the current diversion is
980 # BODY, so as soon as a macro (m4_defun'd) is expanded, we first
981 # record the current diversion under the name _m4_divert_dump (denoted
982 # DUMP below for short). This introduces an important difference with
983 # the previous versions of Autoconf: you cannot use m4_require if you
984 # are not inside an m4_defun'd macro, and especially, you cannot
985 # m4_require directly from the top level.
986 #
987 # We have not tried to simulate the old behavior (better yet, we
988 # diagnose it), because it is too dangerous: a macro m4_require'd from
989 # the top level is expanded before the body of `configure', i.e., before
990 # any other test was run. I let you imagine the result of requiring
991 # AC_STDC_HEADERS for instance, before AC_PROG_CC was actually run....
992 #
993 # After AC_INIT was run, the current diversion is BODY.
994 # * AC_INIT was run
995 # DUMP: undefined
996 # diversion stack: BODY |-
997 #
998 # * TEST1 is expanded
999 # The prologue of TEST1 sets _m4_divert_dump, which is the diversion
1000 # where the current elaboration will be dumped, to the current
1001 # diversion. It also m4_divert_push to GROW, where the full
1002 # expansion of TEST1 and its dependencies will be elaborated.
1003 # DUMP: BODY
1004 # BODY: empty
1005 # diversions: GROW, BODY |-
1006 #
1007 # * TEST1 requires TEST2a
1008 # _m4_require_call m4_divert_pushes another temporary diversion,
1009 # GROW - 1, and expands TEST2a in there.
1010 # DUMP: BODY
1011 # BODY: empty
1012 # GROW - 1: TEST2a
1013 # diversions: GROW - 1, GROW, BODY |-
1014 # Than the content of the temporary diversion is moved to DUMP and the
1015 # temporary diversion is popped.
1016 # DUMP: BODY
1017 # BODY: TEST2a
1018 # diversions: GROW, BODY |-
1019 #
1020 # * TEST1 requires TEST2b
1021 # Again, _m4_require_call pushes GROW - 1 and heads to expand TEST2b.
1022 # DUMP: BODY
1023 # BODY: TEST2a
1024 # diversions: GROW - 1, GROW, BODY |-
1025 #
1026 # * TEST2b requires TEST3
1027 # _m4_require_call pushes GROW - 2 and expands TEST3 here.
1028 # (TEST3 requires TEST2a, but TEST2a has already been m4_provide'd, so
1029 # nothing happens.)
1030 # DUMP: BODY
1031 # BODY: TEST2a
1032 # GROW - 2: TEST3
1033 # diversions: GROW - 2, GROW - 1, GROW, BODY |-
1034 # Than the diversion is appended to DUMP, and popped.
1035 # DUMP: BODY
1036 # BODY: TEST2a; TEST3
1037 # diversions: GROW - 1, GROW, BODY |-
1038 #
1039 # * TEST1 requires TEST2b (contd.)
1040 # The content of TEST2b is expanded...
1041 # DUMP: BODY
1042 # BODY: TEST2a; TEST3
1043 # GROW - 1: TEST2b,
1044 # diversions: GROW - 1, GROW, BODY |-
1045 # ... and moved to DUMP.
1046 # DUMP: BODY
1047 # BODY: TEST2a; TEST3; TEST2b
1048 # diversions: GROW, BODY |-
1049 #
1050 # * TEST1 is expanded: epilogue
1051 # TEST1's own content is in GROW...
1052 # DUMP: BODY
1053 # BODY: TEST2a; TEST3; TEST2b
1054 # GROW: TEST1
1055 # diversions: BODY |-
1056 # ... and it's epilogue moves it to DUMP and then undefines DUMP.
1057 # DUMP: undefined
1058 # BODY: TEST2a; TEST3; TEST2b; TEST1
1059 # diversions: BODY |-
1060 #
1061 #
1062 # 2. Keeping track of the expansion stack
1063 # =======================================
1064 #
1065 # When M4 expansion goes wrong it is often extremely hard to find the
1066 # path amongst macros that drove to the failure. What is needed is
1067 # the stack of macro `calls'. One could imagine that GNU M4 would
1068 # maintain a stack of macro expansions, unfortunately it doesn't, so
1069 # we do it by hand. This is of course extremely costly, but the help
1070 # this stack provides is worth it. Nevertheless to limit the
1071 # performance penalty this is implemented only for m4_defun'd macros,
1072 # not for define'd macros.
1073 #
1074 # The scheme is simplistic: each time we enter an m4_defun'd macros,
1075 # we prepend its name in m4_expansion_stack, and when we exit the
1076 # macro, we remove it (thanks to pushdef/popdef).
1077 #
1078 # In addition, we want to detect circular m4_require dependencies.
1079 # Each time we expand a macro FOO we define _m4_expanding(FOO); and
1080 # m4_require(BAR) simply checks whether _m4_expanding(BAR) is defined.
1081
1082
1083 # m4_expansion_stack_push(TEXT)
1084 # -----------------------------
1085 m4_define([m4_expansion_stack_push],
1086 [m4_pushdef([m4_expansion_stack],
1087 [$1]m4_ifdef([m4_expansion_stack], [
1088 m4_defn([m4_expansion_stack])]))])
1089
1090
1091 # m4_expansion_stack_pop
1092 # ----------------------
1093 m4_define([m4_expansion_stack_pop],
1094 [m4_popdef([m4_expansion_stack])])
1095
1096
1097 # m4_expansion_stack_dump
1098 # -----------------------
1099 # Dump the expansion stack.
1100 m4_define([m4_expansion_stack_dump],
1101 [m4_ifdef([m4_expansion_stack],
1102 [m4_errprintn(m4_defn([m4_expansion_stack]))])dnl
1103 m4_errprintn(m4_location[: the top level])])
1104
1105
1106 # _m4_divert(GROW)
1107 # ----------------
1108 # This diversion is used by the m4_defun/m4_require machinery. It is
1109 # important to keep room before GROW because for each nested
1110 # AC_REQUIRE we use an additional diversion (i.e., two m4_require's
1111 # will use GROW - 2. More than 3 levels has never seemed to be
1112 # needed.)
1113 #
1114 # ...
1115 # - GROW - 2
1116 # m4_require'd code, 2 level deep
1117 # - GROW - 1
1118 # m4_require'd code, 1 level deep
1119 # - GROW
1120 # m4_defun'd macros are elaborated here.
1121
1122 m4_define([_m4_divert(GROW)], 10000)
1123
1124
1125 # _m4_defun_pro(MACRO-NAME)
1126 # -------------------------
1127 # The prologue for Autoconf macros.
1128 m4_define([_m4_defun_pro],
1129 [m4_ifndef([m4_expansion_stack], [_m4_defun_pro_outer[]])dnl
1130 m4_expansion_stack_push(m4_defn([m4_location($1)])[: $1 is expanded from...])dnl
1131 m4_pushdef([_m4_expanding($1)])dnl
1132 ])
1133
1134 m4_define([_m4_defun_pro_outer],
1135 [m4_copy([_m4_divert_diversion], [_m4_divert_dump])dnl
1136 m4_divert_push([GROW])dnl
1137 ])
1138
1139 # _m4_defun_epi(MACRO-NAME)
1140 # -------------------------
1141 # The Epilogue for Autoconf macros. MACRO-NAME only helps tracing
1142 # the PRO/EPI pairs.
1143 m4_define([_m4_defun_epi],
1144 [m4_popdef([_m4_expanding($1)])dnl
1145 m4_expansion_stack_pop()dnl
1146 m4_ifndef([m4_expansion_stack], [_m4_defun_epi_outer[]])dnl
1147 m4_provide([$1])dnl
1148 ])
1149
1150 m4_define([_m4_defun_epi_outer],
1151 [m4_undefine([_m4_divert_dump])dnl
1152 m4_divert_pop([GROW])dnl
1153 m4_undivert([GROW])dnl
1154 ])
1155
1156
1157 # m4_defun(NAME, EXPANSION)
1158 # -------------------------
1159 # Define a macro which automatically provides itself. Add machinery
1160 # so the macro automatically switches expansion to the diversion
1161 # stack if it is not already using it. In this case, once finished,
1162 # it will bring back all the code accumulated in the diversion stack.
1163 # This, combined with m4_require, achieves the topological ordering of
1164 # macros. We don't use this macro to define some frequently called
1165 # macros that are not involved in ordering constraints, to save m4
1166 # processing.
1167 m4_define([m4_defun],
1168 [m4_define([m4_location($1)], m4_location)dnl
1169 m4_define([$1],
1170 [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])])
1171
1172
1173 # m4_defun_once(NAME, EXPANSION)
1174 # ------------------------------
1175 # As m4_defun, but issues the EXPANSION only once, and warns if used
1176 # several times.
1177 m4_define([m4_defun_once],
1178 [m4_define([m4_location($1)], m4_location)dnl
1179 m4_define([$1],
1180 [m4_provide_if([$1],
1181 [m4_warn([syntax], [$1 invoked multiple times])],
1182 [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])])])
1183
1184
1185 # m4_pattern_forbid(ERE, [WHY])
1186 # -----------------------------
1187 # Declare that no token matching the extended regular expression ERE
1188 # should be seen in the output but if...
1189 m4_define([m4_pattern_forbid], [])
1190
1191
1192 # m4_pattern_allow(ERE)
1193 # ---------------------
1194 # ... but if that token matches the extended regular expression ERE.
1195 # Both used via traces.
1196 m4_define([m4_pattern_allow], [])
1197
1198
1199 ## ----------------------------- ##
1200 ## Dependencies between macros. ##
1201 ## ----------------------------- ##
1202
1203
1204 # m4_before(THIS-MACRO-NAME, CALLED-MACRO-NAME)
1205 # ---------------------------------------------
1206 m4_define([m4_before],
1207 [m4_provide_if([$2],
1208 [m4_warn([syntax], [$2 was called before $1])])])
1209
1210
1211 # m4_require(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK])
1212 # -----------------------------------------------------------
1213 # If NAME-TO-CHECK has never been expanded (actually, if it is not
1214 # m4_provide'd), expand BODY-TO-EXPAND *before* the current macro
1215 # expansion. Once expanded, emit it in _m4_divert_dump. Keep track
1216 # of the m4_require chain in m4_expansion_stack.
1217 #
1218 # The normal cases are:
1219 #
1220 # - NAME-TO-CHECK == BODY-TO-EXPAND
1221 # Which you can use for regular macros with or without arguments, e.g.,
1222 # m4_require([AC_PROG_CC], [AC_PROG_CC])
1223 # m4_require([AC_CHECK_HEADERS(limits.h)], [AC_CHECK_HEADERS(limits.h)])
1224 # which is just the same as
1225 # m4_require([AC_PROG_CC])
1226 # m4_require([AC_CHECK_HEADERS(limits.h)])
1227 #
1228 # - BODY-TO-EXPAND == m4_indir([NAME-TO-CHECK])
1229 # In the case of macros with irregular names. For instance:
1230 # m4_require([AC_LANG_COMPILER(C)], [indir([AC_LANG_COMPILER(C)])])
1231 # which means `if the macro named `AC_LANG_COMPILER(C)' (the parens are
1232 # part of the name, it is not an argument) has not been run, then
1233 # call it.'
1234 # Had you used
1235 # m4_require([AC_LANG_COMPILER(C)], [AC_LANG_COMPILER(C)])
1236 # then m4_require would have tried to expand `AC_LANG_COMPILER(C)', i.e.,
1237 # call the macro `AC_LANG_COMPILER' with `C' as argument.
1238 #
1239 # You could argue that `AC_LANG_COMPILER', when it receives an argument
1240 # such as `C' should dispatch the call to `AC_LANG_COMPILER(C)'. But this
1241 # `extension' prevents `AC_LANG_COMPILER' from having actual arguments that
1242 # it passes to `AC_LANG_COMPILER(C)'.
1243 m4_define([m4_require],
1244 [m4_ifdef([_m4_expanding($1)],
1245 [m4_fatal([$0: circular dependency of $1])])dnl
1246 m4_ifndef([_m4_divert_dump],
1247 [m4_fatal([$0($1): cannot be used outside of an m4_defun'd macro])])dnl
1248 m4_provide_if([$1],
1249 [],
1250 [_m4_require_call([$1], [$2])])dnl
1251 ])
1252
1253
1254 # _m4_require_call(BODY-TO-EXPAND)
1255 # --------------------------------
1256 # If m4_require decides to expand the body, it calls this macro.
1257 m4_define([_m4_require_call],
1258 [m4_define([_m4_divert_grow], m4_decr(_m4_divert_grow))dnl
1259 m4_divert_push(_m4_divert_grow)dnl
1260 m4_default([$2], [$1])
1261 m4_provide_if([$1],
1262 [],
1263 [m4_warn([syntax],
1264 [$1 is m4_require'd but not m4_defun'd])])dnl
1265 m4_divert(m4_defn([_m4_divert_dump]))dnl
1266 m4_undivert(_m4_divert_grow)dnl
1267 m4_divert_pop(_m4_divert_grow)dnl
1268 m4_define([_m4_divert_grow], m4_incr(_m4_divert_grow))dnl
1269 ])
1270
1271
1272 # _m4_divert_grow
1273 # ---------------
1274 # The counter for _m4_require_call.
1275 m4_define([_m4_divert_grow], _m4_divert([GROW]))
1276
1277
1278 # m4_expand_once(TEXT, [WITNESS = TEXT])
1279 # --------------------------------------
1280 # If TEXT has never been expanded, expand it *here*. Use WITNESS as
1281 # as a memory that TEXT has already been expanded.
1282 m4_define([m4_expand_once],
1283 [m4_provide_if(m4_ifval([$2], [[$2]], [[$1]]),
1284 [],
1285 [m4_provide(m4_ifval([$2], [[$2]], [[$1]]))[]$1])])
1286
1287
1288 # m4_provide(MACRO-NAME)
1289 # ----------------------
1290 m4_define([m4_provide],
1291 [m4_define([m4_provide($1)])])
1292
1293
1294 # m4_provide_if(MACRO-NAME, IF-PROVIDED, IF-NOT-PROVIDED)
1295 # -------------------------------------------------------
1296 # If MACRO-NAME is provided do IF-PROVIDED, else IF-NOT-PROVIDED.
1297 # The purpose of this macro is to provide the user with a means to
1298 # check macros which are provided without letting her know how the
1299 # information is coded.
1300 m4_define([m4_provide_if],
1301 [m4_ifdef([m4_provide($1)],
1302 [$2], [$3])])
1303
1304
1305 ## -------------------- ##
1306 ## 9. Text processing. ##
1307 ## -------------------- ##
1308
1309
1310 # m4_cr_letters
1311 # m4_cr_LETTERS
1312 # m4_cr_Letters
1313 # -------------
1314 m4_define([m4_cr_letters], [abcdefghijklmnopqrstuvwxyz])
1315 m4_define([m4_cr_LETTERS], [ABCDEFGHIJKLMNOPQRSTUVWXYZ])
1316 m4_define([m4_cr_Letters],
1317 m4_defn([m4_cr_letters])dnl
1318 m4_defn([m4_cr_LETTERS])dnl
1319 )
1320
1321
1322 # m4_cr_digits
1323 # ------------
1324 m4_define([m4_cr_digits], [0123456789])
1325
1326
1327 # m4_cr_symbols1 & m4_cr_symbols2
1328 # -------------------------------
1329 m4_define([m4_cr_symbols1],
1330 m4_defn([m4_cr_Letters])dnl
1331 _)
1332
1333 m4_define([m4_cr_symbols2],
1334 m4_defn([m4_cr_symbols1])dnl
1335 m4_defn([m4_cr_digits])dnl
1336 )
1337
1338
1339 # m4_re_escape(STRING)
1340 # --------------------
1341 # Escape RE active characters in STRING.
1342 m4_define([m4_re_escape],
1343 [m4_bpatsubst([$1],
1344 [[][*+.?\^$]], [\\\&])])
1345
1346
1347 # m4_re_string
1348 # ------------
1349 # Regexp for `[a-zA-Z_0-9]*'
1350 # m4_dquote provides literal [] for the character class.
1351 m4_define([m4_re_string],
1352 m4_dquote(m4_defn([m4_cr_symbols2]))dnl
1353 [*]dnl
1354 )
1355
1356
1357 # m4_re_word
1358 # ----------
1359 # Regexp for `[a-zA-Z_][a-zA-Z_0-9]*'
1360 m4_define([m4_re_word],
1361 m4_dquote(m4_defn([m4_cr_symbols1]))dnl
1362 m4_defn([m4_re_string])dnl
1363 )
1364
1365
1366 # m4_tolower(STRING)
1367 # m4_toupper(STRING)
1368 # ------------------
1369 # These macros lowercase and uppercase strings.
1370 m4_define([m4_tolower],
1371 [m4_translit([$1], m4_defn([m4_cr_LETTERS]), m4_defn([m4_cr_letters]))])
1372 m4_define([m4_toupper],
1373 [m4_translit([$1], m4_defn([m4_cr_letters]), m4_defn([m4_cr_LETTERS]))])
1374
1375
1376 # m4_split(STRING, [REGEXP])
1377 # --------------------------
1378 #
1379 # Split STRING into an m4 list of quoted elements. The elements are
1380 # quoted with [ and ]. Beginning spaces and end spaces *are kept*.
1381 # Use m4_strip to remove them.
1382 #
1383 # REGEXP specifies where to split. Default is [\t ]+.
1384 #
1385 # If STRING is empty, the result is an empty list.
1386 #
1387 # Pay attention to the m4_changequotes. When m4 reads the definition of
1388 # m4_split, it still has quotes set to [ and ]. Luckily, these are matched
1389 # in the macro body, so the definition is stored correctly.
1390 #
1391 # Also, notice that $1 is quoted twice, since we want the result to
1392 # be quoted. Then you should understand that the argument of
1393 # patsubst is ``STRING'' (i.e., with additional `` and '').
1394 #
1395 # This macro is safe on active symbols, i.e.:
1396 # m4_define(active, ACTIVE)
1397 # m4_split([active active ])end
1398 # => [active], [active], []end
1399
1400 m4_define([m4_split],
1401 [m4_ifval([$1], [_m4_split($@)])])
1402
1403 m4_define([_m4_split],
1404 [m4_changequote(``, '')dnl
1405 [dnl Can't use m4_default here instead of m4_if, because m4_default uses
1406 dnl [ and ] as quotes.
1407 m4_bpatsubst(````$1'''',
1408 m4_if(``$2'',, ``[ ]+'', ``$2''),
1409 ``], ['')]dnl
1410 m4_changequote([, ])])
1411
1412
1413
1414 # m4_flatten(STRING)
1415 # ------------------
1416 # If STRING contains end of lines, replace them with spaces. If there
1417 # are backslashed end of lines, remove them. This macro is safe with
1418 # active symbols.
1419 # m4_define(active, ACTIVE)
1420 # m4_flatten([active
1421 # act\
1422 # ive])end
1423 # => active activeend
1424 m4_define([m4_flatten],
1425 [m4_translit(m4_bpatsubst([[[$1]]], [\\
1426 ]), [
1427 ], [ ])])
1428
1429
1430 # m4_strip(STRING)
1431 # ----------------
1432 # Expands into STRING with tabs and spaces singled out into a single
1433 # space, and removing leading and trailing spaces.
1434 #
1435 # This macro is robust to active symbols.
1436 # m4_define(active, ACTIVE)
1437 # m4_strip([ active <tab> <tab>active ])end
1438 # => active activeend
1439 #
1440 # Because we want to preserve active symbols, STRING must be double-quoted.
1441 #
1442 # Then notice the 2 last patterns: they are in charge of removing the
1443 # leading/trailing spaces. Why not just `[^ ]'? Because they are
1444 # applied to doubly quoted strings, i.e. more or less [[STRING]]. So
1445 # if there is a leading space in STRING, then it is the *third*
1446 # character, since there are two leading `['; equally for the last pattern.
1447 m4_define([m4_strip],
1448 [m4_bpatsubsts([[$1]],
1449 [[ ]+], [ ],
1450 [^\(..\) ], [\1],
1451 [ \(..\)$], [\1])])
1452
1453
1454 # m4_normalize(STRING)
1455 # --------------------
1456 # Apply m4_flatten and m4_strip to STRING.
1457 #
1458 # The argument is quoted, so that the macro is robust to active symbols:
1459 #
1460 # m4_define(active, ACTIVE)
1461 # m4_normalize([ act\
1462 # ive
1463 # active ])end
1464 # => active activeend
1465
1466 m4_define([m4_normalize],
1467 [m4_strip(m4_flatten([$1]))])
1468
1469
1470
1471 # m4_join(SEP, ARG1, ARG2...)
1472 # ---------------------------
1473 # Produce ARG1SEPARG2...SEPARGn.
1474 m4_defun([m4_join],
1475 [m4_case([$#],
1476 [1], [],
1477 [2], [[$2]],
1478 [[$2][$1]$0([$1], m4_shiftn(2, $@))])])
1479
1480
1481
1482 # m4_append(MACRO-NAME, STRING, [SEPARATOR])
1483 # ------------------------------------------
1484 # Redefine MACRO-NAME to hold its former content plus `SEPARATOR`'STRING'
1485 # at the end. It is valid to use this macro with MACRO-NAME undefined,
1486 # in which case no SEPARATOR is added. Be aware that the criterion is
1487 # `not being defined', and not `not being empty'.
1488 #
1489 # This macro is robust to active symbols. It can be used to grow
1490 # strings.
1491 #
1492 # | m4_define(active, ACTIVE)
1493 # | m4_append([sentence], [This is an])
1494 # | m4_append([sentence], [ active ])
1495 # | m4_append([sentence], [symbol.])
1496 # | sentence
1497 # | m4_undefine([active])dnl
1498 # | sentence
1499 # => This is an ACTIVE symbol.
1500 # => This is an active symbol.
1501 #
1502 # It can be used to define hooks.
1503 #
1504 # | m4_define(active, ACTIVE)
1505 # | m4_append([hooks], [m4_define([act1], [act2])])
1506 # | m4_append([hooks], [m4_define([act2], [active])])
1507 # | m4_undefine([active])
1508 # | act1
1509 # | hooks
1510 # | act1
1511 # => act1
1512 # =>
1513 # => active
1514 m4_define([m4_append],
1515 [m4_define([$1],
1516 m4_ifdef([$1], [m4_defn([$1])$3])[$2])])
1517
1518 # m4_prepend(MACRO-NAME, STRING, [SEPARATOR])
1519 # -------------------------------------------
1520 # Same, but prepend.
1521 m4_define([m4_prepend],
1522 [m4_define([$1],
1523 [$2]m4_ifdef([$1], [$3[]m4_defn([$1])]))])
1524
1525 # m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR])
1526 # -----------------------------------------------
1527 # As `m4_append', but append only if not yet present.
1528 m4_define([m4_append_uniq],
1529 [m4_ifdef([$1],
1530 [m4_bmatch([$3]m4_defn([$1])[$3], m4_re_escape([$3$2$3]), [],
1531 [m4_append($@)])],
1532 [m4_append($@)])])
1533
1534
1535 # m4_text_wrap(STRING, [PREFIX], [FIRST-PREFIX], [WIDTH])
1536 # -------------------------------------------------------
1537 # Expands into STRING wrapped to hold in WIDTH columns (default = 79).
1538 # If PREFIX is given, each line is prefixed with it. If FIRST-PREFIX is
1539 # specified, then the first line is prefixed with it. As a special case,
1540 # if the length of FIRST-PREFIX is greater than that of PREFIX, then
1541 # FIRST-PREFIX will be left alone on the first line.
1542 #
1543 # Typical outputs are:
1544 #
1545 # m4_text_wrap([Short string */], [ ], [/* ], 20)
1546 # => /* Short string */
1547 #
1548 # m4_text_wrap([Much longer string */], [ ], [/* ], 20)
1549 # => /* Much longer
1550 # => string */
1551 #
1552 # m4_text_wrap([Short doc.], [ ], [ --short ], 30)
1553 # => --short Short doc.
1554 #
1555 # m4_text_wrap([Short doc.], [ ], [ --too-wide ], 30)
1556 # => --too-wide
1557 # => Short doc.
1558 #
1559 # m4_text_wrap([Super long documentation.], [ ], [ --too-wide ], 30)
1560 # => --too-wide
1561 # => Super long
1562 # => documentation.
1563 #
1564 # FIXME: there is no checking of a longer PREFIX than WIDTH, but do
1565 # we really want to bother with people trying each single corner
1566 # of a software?
1567 #
1568 # more important:
1569 # FIXME: handle quadrigraphs correctly, both in TEXT and in FIRST_PREFIX.
1570 #
1571 # This macro does not leave a trailing space behind the last word,
1572 # what complicates it a bit. The algorithm is stupid simple: all the
1573 # words are preceded by m4_Separator which is defined to empty for the
1574 # first word, and then ` ' (single space) for all the others.
1575 m4_define([m4_text_wrap],
1576 [m4_pushdef([m4_Prefix], [$2])dnl
1577 m4_pushdef([m4_Prefix1], m4_default([$3], [m4_Prefix]))dnl
1578 m4_pushdef([m4_Width], m4_default([$4], 79))dnl
1579 m4_pushdef([m4_Cursor], m4_len(m4_Prefix1))dnl
1580 m4_pushdef([m4_Separator], [])dnl
1581 m4_Prefix1[]dnl
1582 m4_if(m4_eval(m4_Cursor > m4_len(m4_Prefix)),
1583 1, [m4_define([m4_Cursor], m4_len(m4_Prefix))
1584 m4_Prefix])[]dnl
1585 m4_foreach_w([m4_Word], [$1],
1586 [m4_define([m4_Cursor], m4_eval(m4_Cursor + m4_len(m4_defn([m4_Word])) + 1))dnl
1587 dnl New line if too long, else insert a space unless it is the first
1588 dnl of the words.
1589 m4_if(m4_eval(m4_Cursor > m4_Width),
1590 1, [m4_define([m4_Cursor],
1591 m4_eval(m4_len(m4_Prefix) + m4_len(m4_defn([m4_Word])) + 1))]
1592 m4_Prefix,
1593 [m4_Separator])[]dnl
1594 m4_defn([m4_Word])[]dnl
1595 m4_define([m4_Separator], [ ])])dnl
1596 m4_popdef([m4_Separator])dnl
1597 m4_popdef([m4_Cursor])dnl
1598 m4_popdef([m4_Width])dnl
1599 m4_popdef([m4_Prefix1])dnl
1600 m4_popdef([m4_Prefix])dnl
1601 ])
1602
1603
1604 # m4_text_box(MESSAGE, [FRAME-CHARACTER = `-'])
1605 # ---------------------------------------------
1606 m4_define([m4_text_box],
1607 [@%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@
1608 @%:@@%:@ $1 @%:@@%:@
1609 @%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@[]dnl
1610 ])
1611
1612
1613 # m4_qlen(STRING)
1614 # ---------------
1615 # Expands to the length of STRING after autom4te converts all quadrigraphs.
1616 m4_define([m4_qlen],
1617 [m4_len(m4_bpatsubsts([[$1]], [@\(<:\|:>\|S|\|%:\)@], [P], [@&t@]))])
1618
1619
1620 # m4_qdelta(STRING)
1621 # -----------------
1622 # Expands to the net change in the length of STRING from autom4te converting the
1623 # quadrigraphs in STRING. This number is always negative or zero.
1624 m4_define([m4_qdelta],
1625 [m4_eval(m4_qlen([$1]) - m4_len([$1]))])
1626
1627
1628
1629 ## ----------------------- ##
1630 ## 10. Number processing. ##
1631 ## ----------------------- ##
1632
1633 # m4_sign(A)
1634 # ----------
1635 #
1636 # The sign of the integer A.
1637 m4_define([m4_sign],
1638 [m4_bmatch([$1],
1639 [^-], -1,
1640 [^0+], 0,
1641 1)])
1642
1643 # m4_cmp(A, B)
1644 # ------------
1645 #
1646 # Compare two integers.
1647 # A < B -> -1
1648 # A = B -> 0
1649 # A > B -> 1
1650 m4_define([m4_cmp],
1651 [m4_sign(m4_eval([$1 - $2]))])
1652
1653
1654 # m4_list_cmp(A, B)
1655 # -----------------
1656 #
1657 # Compare the two lists of integers A and B. For instance:
1658 # m4_list_cmp((1, 0), (1)) -> 0
1659 # m4_list_cmp((1, 0), (1, 0)) -> 0
1660 # m4_list_cmp((1, 2), (1, 0)) -> 1
1661 # m4_list_cmp((1, 2, 3), (1, 2)) -> 1
1662 # m4_list_cmp((1, 2, -3), (1, 2)) -> -1
1663 # m4_list_cmp((1, 0), (1, 2)) -> -1
1664 # m4_list_cmp((1), (1, 2)) -> -1
1665 m4_define([m4_list_cmp],
1666 [m4_if([$1$2], [()()], 0,
1667 [$1], [()], [$0((0), [$2])],
1668 [$2], [()], [$0([$1], (0))],
1669 [m4_case(m4_cmp(m4_car$1, m4_car$2),
1670 -1, -1,
1671 1, 1,
1672 0, [$0((m4_shift$1), (m4_shift$2))])])])
1673
1674
1675
1676 ## ------------------------ ##
1677 ## 11. Version processing. ##
1678 ## ------------------------ ##
1679
1680
1681 # m4_version_unletter(VERSION)
1682 # ----------------------------
1683 # Normalize beta version numbers with letters to numbers only for comparison.
1684 #
1685 # Nl -> (N+1).-1.(l#)
1686 #
1687 #i.e., 2.14a -> 2.15.-1.1, 2.14b -> 2.15.-1.2, etc.
1688 # This macro is absolutely not robust to active macro, it expects
1689 # reasonable version numbers and is valid up to `z', no double letters.
1690 m4_define([m4_version_unletter],
1691 [m4_translit(m4_bpatsubsts([$1],
1692 [\([0-9]+\)\([abcdefghi]\)],
1693 [m4_eval(\1 + 1).-1.\2],
1694 [\([0-9]+\)\([jklmnopqrs]\)],
1695 [m4_eval(\1 + 1).-1.1\2],
1696 [\([0-9]+\)\([tuvwxyz]\)],
1697 [m4_eval(\1 + 1).-1.2\2]),
1698 [abcdefghijklmnopqrstuvwxyz],
1699 [12345678901234567890123456])])
1700
1701
1702 # m4_version_compare(VERSION-1, VERSION-2)
1703 # ----------------------------------------
1704 # Compare the two version numbers and expand into
1705 # -1 if VERSION-1 < VERSION-2
1706 # 0 if =
1707 # 1 if >
1708 m4_define([m4_version_compare],
1709 [m4_list_cmp((m4_split(m4_version_unletter([$1]), [\.])),
1710 (m4_split(m4_version_unletter([$2]), [\.])))])
1711
1712
1713 # m4_PACKAGE_NAME
1714 # m4_PACKAGE_TARNAME
1715 # m4_PACKAGE_VERSION
1716 # m4_PACKAGE_STRING
1717 # m4_PACKAGE_BUGREPORT
1718 # --------------------
1719 #m4_include([m4sugar/version.m4]) # This is needed for Autoconf, but not Bison.
1720
1721
1722 # m4_version_prereq(VERSION, [IF-OK], [IF-NOT = FAIL])
1723 # ----------------------------------------------------
1724 # Check this Autoconf version against VERSION.
1725 m4_define([m4_version_prereq],
1726 [m4_if(m4_version_compare(m4_defn([m4_PACKAGE_VERSION]), [$1]), -1,
1727 [m4_default([$3],
1728 [m4_fatal([Autoconf version $1 or higher is required],
1729 63)])],
1730 [$2])[]dnl
1731 ])
1732
1733
1734
1735 ## ------------------- ##
1736 ## 12. File handling. ##
1737 ## ------------------- ##
1738
1739
1740 # It is a real pity that M4 comes with no macros to bind a diversion
1741 # to a file. So we have to deal without, which makes us a lot more
1742 # fragile that we should.
1743
1744
1745 # m4_file_append(FILE-NAME, CONTENT)
1746 # ----------------------------------
1747 m4_define([m4_file_append],
1748 [m4_syscmd([cat >>$1 <<_m4eof
1749 $2
1750 _m4eof
1751 ])
1752 m4_if(m4_sysval, [0], [],
1753 [m4_fatal([$0: cannot write: $1])])])
1754
1755
1756
1757 ## ------------------------ ##
1758 ## 13. Setting M4sugar up. ##
1759 ## ------------------------ ##
1760
1761
1762 # m4_init
1763 # -------
1764 m4_define([m4_init],
1765 [# All the M4sugar macros start with `m4_', except `dnl' kept as is
1766 # for sake of simplicity.
1767 m4_pattern_forbid([^_?m4_])
1768 m4_pattern_forbid([^dnl$])
1769
1770 # Check the divert push/pop perfect balance.
1771 m4_wrap([m4_ifdef([_m4_divert_diversion],
1772 [m4_fatal([$0: unbalanced m4_divert_push:]_m4_divert_n_stack)])[]])
1773
1774 m4_divert_push([KILL])
1775 m4_wrap([m4_divert_pop([KILL])[]])
1776 ])
bison