data/m4sugar/m4sugar.m4

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  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
1519 # m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR])
1520 # -----------------------------------------------
1521 # As `m4_append', but append only if not yet present.
1522 m4_define([m4_append_uniq],
1523 [m4_ifdef([$1],
1524           [m4_bmatch([$3]m4_defn([$1])[$3], m4_re_escape([$3$2$3]), [],
1525                      [m4_append($@)])],
1526           [m4_append($@)])])
1527
1528
1529 # m4_text_wrap(STRING, [PREFIX], [FIRST-PREFIX], [WIDTH])
1530 # -------------------------------------------------------
1531 # Expands into STRING wrapped to hold in WIDTH columns (default = 79).
1532 # If PREFIX is given, each line is prefixed with it.  If FIRST-PREFIX is
1533 # specified, then the first line is prefixed with it.  As a special case,
1534 # if the length of FIRST-PREFIX is greater than that of PREFIX, then
1535 # FIRST-PREFIX will be left alone on the first line.
1536 #
1537 # Typical outputs are:
1538 #
1539 # m4_text_wrap([Short string */], [   ], [/* ], 20)
1540 #  => /* Short string */
1541 #
1542 # m4_text_wrap([Much longer string */], [   ], [/* ], 20)
1543 #  => /* Much longer
1544 #  =>    string */
1545 #
1546 # m4_text_wrap([Short doc.], [          ], [  --short ], 30)
1547 #  =>   --short Short doc.
1548 #
1549 # m4_text_wrap([Short doc.], [          ], [  --too-wide ], 30)
1550 #  =>   --too-wide
1551 #  =>           Short doc.
1552 #
1553 # m4_text_wrap([Super long documentation.], [          ], [  --too-wide ], 30)
1554 #  =>   --too-wide
1555 #  =>      Super long
1556 #  =>      documentation.
1557 #
1558 # FIXME: there is no checking of a longer PREFIX than WIDTH, but do
1559 # we really want to bother with people trying each single corner
1560 # of a software?
1561 #
1562 # more important:
1563 # FIXME: handle quadrigraphs correctly, both in TEXT and in FIRST_PREFIX.
1564 #
1565 # This macro does not leave a trailing space behind the last word,
1566 # what complicates it a bit.  The algorithm is stupid simple: all the
1567 # words are preceded by m4_Separator which is defined to empty for the
1568 # first word, and then ` ' (single space) for all the others.
1569 m4_define([m4_text_wrap],
1570 [m4_pushdef([m4_Prefix], [$2])dnl
1571 m4_pushdef([m4_Prefix1], m4_default([$3], [m4_Prefix]))dnl
1572 m4_pushdef([m4_Width], m4_default([$4], 79))dnl
1573 m4_pushdef([m4_Cursor], m4_len(m4_Prefix1))dnl
1574 m4_pushdef([m4_Separator], [])dnl
1575 m4_Prefix1[]dnl
1576 m4_if(m4_eval(m4_Cursor > m4_len(m4_Prefix)),
1577       1, [m4_define([m4_Cursor], m4_len(m4_Prefix))
1578 m4_Prefix])[]dnl
1579 m4_foreach_w([m4_Word], [$1],
1580 [m4_define([m4_Cursor], m4_eval(m4_Cursor + m4_len(m4_defn([m4_Word])) + 1))dnl
1581 dnl New line if too long, else insert a space unless it is the first
1582 dnl of the words.
1583 m4_if(m4_eval(m4_Cursor > m4_Width),
1584       1, [m4_define([m4_Cursor],
1585                     m4_eval(m4_len(m4_Prefix) + m4_len(m4_defn([m4_Word])) + 1))]
1586 m4_Prefix,
1587        [m4_Separator])[]dnl
1588 m4_defn([m4_Word])[]dnl
1589 m4_define([m4_Separator], [ ])])dnl
1590 m4_popdef([m4_Separator])dnl
1591 m4_popdef([m4_Cursor])dnl
1592 m4_popdef([m4_Width])dnl
1593 m4_popdef([m4_Prefix1])dnl
1594 m4_popdef([m4_Prefix])dnl
1595 ])
1596
1597
1598 # m4_text_box(MESSAGE, [FRAME-CHARACTER = `-'])
1599 # ---------------------------------------------
1600 m4_define([m4_text_box],
1601 [@%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@
1602 @%:@@%:@ $1 @%:@@%:@
1603 @%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@[]dnl
1604 ])
1605
1606
1607 # m4_qlen(STRING)
1608 # ---------------
1609 # Expands to the length of STRING after autom4te converts all quadrigraphs.
1610 m4_define([m4_qlen],
1611 [m4_len(m4_bpatsubsts([[$1]], [@\(<:\|:>\|S|\|%:\)@], [P], [@&t@]))])
1612
1613
1614 # m4_qdelta(STRING)
1615 # -----------------
1616 # Expands to the net change in the length of STRING from autom4te converting the
1617 # quadrigraphs in STRING.  This number is always negative or zero.
1618 m4_define([m4_qdelta],
1619 [m4_eval(m4_qlen([$1]) - m4_len([$1]))])
1620
1621
1622
1623 ## ----------------------- ##
1624 ## 10. Number processing.  ##
1625 ## ----------------------- ##
1626
1627 # m4_sign(A)
1628 # ----------
1629 #
1630 # The sign of the integer A.
1631 m4_define([m4_sign],
1632 [m4_bmatch([$1],
1633            [^-], -1,
1634            [^0+], 0,
1635                   1)])
1636
1637 # m4_cmp(A, B)
1638 # ------------
1639 #
1640 # Compare two integers.
1641 # A < B -> -1
1642 # A = B ->  0
1643 # A > B ->  1
1644 m4_define([m4_cmp],
1645 [m4_sign(m4_eval([$1 - $2]))])
1646
1647
1648 # m4_list_cmp(A, B)
1649 # -----------------
1650 #
1651 # Compare the two lists of integers A and B.  For instance:
1652 #   m4_list_cmp((1, 0),     (1))    ->  0
1653 #   m4_list_cmp((1, 0),     (1, 0)) ->  0
1654 #   m4_list_cmp((1, 2),     (1, 0)) ->  1
1655 #   m4_list_cmp((1, 2, 3),  (1, 2)) ->  1
1656 #   m4_list_cmp((1, 2, -3), (1, 2)) -> -1
1657 #   m4_list_cmp((1, 0),     (1, 2)) -> -1
1658 #   m4_list_cmp((1),        (1, 2)) -> -1
1659 m4_define([m4_list_cmp],
1660 [m4_if([$1$2], [()()], 0,
1661        [$1], [()], [$0((0), [$2])],
1662        [$2], [()], [$0([$1], (0))],
1663        [m4_case(m4_cmp(m4_car$1, m4_car$2),
1664                 -1, -1,
1665                  1, 1,
1666                  0, [$0((m4_shift$1), (m4_shift$2))])])])
1667
1668
1669
1670 ## ------------------------ ##
1671 ## 11. Version processing.  ##
1672 ## ------------------------ ##
1673
1674
1675 # m4_version_unletter(VERSION)
1676 # ----------------------------
1677 # Normalize beta version numbers with letters to numbers only for comparison.
1678 #
1679 #   Nl -> (N+1).-1.(l#)
1680 #
1681 #i.e., 2.14a -> 2.15.-1.1, 2.14b -> 2.15.-1.2, etc.
1682 # This macro is absolutely not robust to active macro, it expects
1683 # reasonable version numbers and is valid up to `z', no double letters.
1684 m4_define([m4_version_unletter],
1685 [m4_translit(m4_bpatsubsts([$1],
1686                            [\([0-9]+\)\([abcdefghi]\)],
1687                              [m4_eval(\1 + 1).-1.\2],
1688                            [\([0-9]+\)\([jklmnopqrs]\)],
1689                              [m4_eval(\1 + 1).-1.1\2],
1690                            [\([0-9]+\)\([tuvwxyz]\)],
1691                              [m4_eval(\1 + 1).-1.2\2]),
1692              [abcdefghijklmnopqrstuvwxyz],
1693              [12345678901234567890123456])])
1694
1695
1696 # m4_version_compare(VERSION-1, VERSION-2)
1697 # ----------------------------------------
1698 # Compare the two version numbers and expand into
1699 #  -1 if VERSION-1 < VERSION-2
1700 #   0 if           =
1701 #   1 if           >
1702 m4_define([m4_version_compare],
1703 [m4_list_cmp((m4_split(m4_version_unletter([$1]), [\.])),
1704              (m4_split(m4_version_unletter([$2]), [\.])))])
1705
1706
1707 # m4_PACKAGE_NAME
1708 # m4_PACKAGE_TARNAME
1709 # m4_PACKAGE_VERSION
1710 # m4_PACKAGE_STRING
1711 # m4_PACKAGE_BUGREPORT
1712 # --------------------
1713 #m4_include([m4sugar/version.m4]) # This is needed for Autoconf, but not Bison.
1714
1715
1716 # m4_version_prereq(VERSION, [IF-OK], [IF-NOT = FAIL])
1717 # ----------------------------------------------------
1718 # Check this Autoconf version against VERSION.
1719 m4_define([m4_version_prereq],
1720 [m4_if(m4_version_compare(m4_defn([m4_PACKAGE_VERSION]), [$1]), -1,
1721        [m4_default([$3],
1722                    [m4_fatal([Autoconf version $1 or higher is required],
1723                              63)])],
1724        [$2])[]dnl
1725 ])
1726
1727
1728
1729 ## ------------------- ##
1730 ## 12. File handling.  ##
1731 ## ------------------- ##
1732
1733
1734 # It is a real pity that M4 comes with no macros to bind a diversion
1735 # to a file.  So we have to deal without, which makes us a lot more
1736 # fragile that we should.
1737
1738
1739 # m4_file_append(FILE-NAME, CONTENT)
1740 # ----------------------------------
1741 m4_define([m4_file_append],
1742 [m4_syscmd([cat >>$1 <<_m4eof
1743 $2
1744 _m4eof
1745 ])
1746 m4_if(m4_sysval, [0], [],
1747       [m4_fatal([$0: cannot write: $1])])])
1748
1749
1750
1751 ## ------------------------ ##
1752 ## 13. Setting M4sugar up.  ##
1753 ## ------------------------ ##
1754
1755
1756 # m4_init
1757 # -------
1758 m4_define([m4_init],
1759 [# All the M4sugar macros start with `m4_', except `dnl' kept as is
1760 # for sake of simplicity.
1761 m4_pattern_forbid([^_?m4_])
1762 m4_pattern_forbid([^dnl$])
1763
1764 # Check the divert push/pop perfect balance.
1765 m4_wrap([m4_ifdef([_m4_divert_diversion],
1766            [m4_fatal([$0: unbalanced m4_divert_push:]_m4_divert_n_stack)])[]])
1767
1768 m4_divert_push([KILL])
1769 m4_wrap([m4_divert_pop([KILL])[]])
1770 ])