1 divert(-1)# -*- Autoconf -*- 2 # This file is part of Autoconf. 3 # Base M4 layer. 4 # Requires GNU M4. 5 # 6 # Copyright (C) 1999-2012 Free Software Foundation, Inc. 7 8 # This file is part of Autoconf. This program is free 9 # software; you can redistribute it and/or modify it under the 10 # terms of the GNU General Public License as published by the 11 # Free Software Foundation, either version 3 of the License, or 12 # (at your option) 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 # Under Section 7 of GPL version 3, you are granted additional 20 # permissions described in the Autoconf Configure Script Exception, 21 # version 3.0, as published by the Free Software Foundation. 22 # 23 # You should have received a copy of the GNU General Public License 24 # and a copy of the Autoconf Configure Script Exception along with 25 # this program; see the files COPYINGv3 and COPYING.EXCEPTION 26 # respectively. If not, see <http://www.gnu.org/licenses/>. 27 28 # Written by Akim Demaille. 29 30 # Set the quotes, whatever the current quoting system. 31 changequote() 32 changequote([, ]) 33 34 # Some old m4's don't support m4exit. But they provide 35 # equivalent functionality by core dumping because of the 36 # long macros we define. 37 ifdef([__gnu__], , 38 [errprint(M4sugar requires GNU M4. Install it before installing M4sugar or 39 set the M4 environment variable to its absolute file name.) 40 m4exit(2)]) 41 42 43 ## ------------------------------- ## 44 ## 1. Simulate --prefix-builtins. ## 45 ## ------------------------------- ## 46 47 # m4_define 48 # m4_defn 49 # m4_undefine 50 define([m4_define], defn([define])) 51 define([m4_defn], defn([defn])) 52 define([m4_undefine], defn([undefine])) 53 54 m4_undefine([define]) 55 m4_undefine([defn]) 56 m4_undefine([undefine]) 57 58 59 # m4_copy(SRC, DST) 60 # ----------------- 61 # Define DST as the definition of SRC. 62 # What's the difference between: 63 # 1. m4_copy([from], [to]) 64 # 2. m4_define([to], [from($@)]) 65 # Well, obviously 1 is more expensive in space. Maybe 2 is more expensive 66 # in time, but because of the space cost of 1, it's not that obvious. 67 # Nevertheless, one huge difference is the handling of `$0'. If `from' 68 # uses `$0', then with 1, `to''s `$0' is `to', while it is `from' in 2. 69 # The user would certainly prefer to see `to'. 70 # 71 # This definition is in effect during m4sugar initialization, when 72 # there are no pushdef stacks; later on, we redefine it to something 73 # more powerful for all other clients to use. 74 m4_define([m4_copy], 75 [m4_define([$2], m4_defn([$1]))]) 76 77 78 # m4_rename(SRC, DST) 79 # ------------------- 80 # Rename the macro SRC to DST. 81 m4_define([m4_rename], 82 [m4_copy([$1], [$2])m4_undefine([$1])]) 83 84 85 # m4_rename_m4(MACRO-NAME) 86 # ------------------------ 87 # Rename MACRO-NAME to m4_MACRO-NAME. 88 m4_define([m4_rename_m4], 89 [m4_rename([$1], [m4_$1])]) 90 91 92 # m4_copy_unm4(m4_MACRO-NAME) 93 # --------------------------- 94 # Copy m4_MACRO-NAME to MACRO-NAME. 95 m4_define([m4_copy_unm4], 96 [m4_copy([$1], m4_bpatsubst([$1], [^m4_\(.*\)], [[\1]]))]) 97 98 99 # Some m4 internals have names colliding with tokens we might use. 100 # Rename them a` la `m4 --prefix-builtins'. Conditionals first, since 101 # some subsequent renames are conditional. 102 m4_rename_m4([ifdef]) 103 m4_rename([ifelse], [m4_if]) 104 105 m4_rename_m4([builtin]) 106 m4_rename_m4([changecom]) 107 m4_rename_m4([changequote]) 108 m4_ifdef([changeword],dnl conditionally available in 1.4.x 109 [m4_undefine([changeword])]) 110 m4_rename_m4([debugfile]) 111 m4_rename_m4([debugmode]) 112 m4_rename_m4([decr]) 113 m4_rename_m4([divnum]) 114 m4_rename_m4([dumpdef]) 115 m4_rename_m4([errprint]) 116 m4_rename_m4([esyscmd]) 117 m4_rename_m4([eval]) 118 m4_rename_m4([format]) 119 m4_undefine([include]) 120 m4_rename_m4([incr]) 121 m4_rename_m4([index]) 122 m4_rename_m4([indir]) 123 m4_rename_m4([len]) 124 m4_rename([m4exit], [m4_exit]) 125 m4_undefine([m4wrap]) 126 m4_ifdef([mkstemp],dnl added in M4 1.4.8 127 [m4_rename_m4([mkstemp]) 128 m4_copy([m4_mkstemp], [m4_maketemp]) 129 m4_undefine([maketemp])], 130 [m4_rename_m4([maketemp]) 131 m4_copy([m4_maketemp], [m4_mkstemp])]) 132 m4_rename([patsubst], [m4_bpatsubst]) 133 m4_rename_m4([popdef]) 134 m4_rename_m4([pushdef]) 135 m4_rename([regexp], [m4_bregexp]) 136 m4_rename_m4([shift]) 137 m4_undefine([sinclude]) 138 m4_rename_m4([substr]) 139 m4_ifdef([symbols],dnl present only in alpha-quality 1.4o 140 [m4_rename_m4([symbols])]) 141 m4_rename_m4([syscmd]) 142 m4_rename_m4([sysval]) 143 m4_rename_m4([traceoff]) 144 m4_rename_m4([traceon]) 145 m4_rename_m4([translit]) 146 147 # _m4_defn(ARG) 148 # ------------- 149 # _m4_defn is for internal use only - it bypasses the wrapper, so it 150 # must only be used on one argument at a time, and only on macros 151 # known to be defined. Make sure this still works if the user renames 152 # m4_defn but not _m4_defn. 153 m4_copy([m4_defn], [_m4_defn]) 154 155 # _m4_divert_raw(NUM) 156 # ------------------- 157 # _m4_divert_raw is for internal use only. Use this instead of 158 # m4_builtin([divert], NUM), so that tracing diversion flow is easier. 159 m4_rename([divert], [_m4_divert_raw]) 160 161 # _m4_popdef(ARG...) 162 # ------------------ 163 # _m4_popdef is for internal use only - it bypasses the wrapper, so it 164 # must only be used on macros known to be defined. Make sure this 165 # still works if the user renames m4_popdef but not _m4_popdef. 166 m4_copy([m4_popdef], [_m4_popdef]) 167 168 # _m4_undefine(ARG...) 169 # -------------------- 170 # _m4_undefine is for internal use only - it bypasses the wrapper, so 171 # it must only be used on macros known to be defined. Make sure this 172 # still works if the user renames m4_undefine but not _m4_undefine. 173 m4_copy([m4_undefine], [_m4_undefine]) 174 175 # _m4_undivert(NUM...) 176 # -------------------- 177 # _m4_undivert is for internal use only, and should always be given 178 # arguments. Use this instead of m4_builtin([undivert], NUM...), so 179 # that tracing diversion flow is easier. 180 m4_rename([undivert], [_m4_undivert]) 181 182 183 ## ------------------- ## 184 ## 2. Error messages. ## 185 ## ------------------- ## 186 187 188 # m4_location 189 # ----------- 190 # Output the current file, colon, and the current line number. 191 m4_define([m4_location], 192 [__file__:__line__]) 193 194 195 # m4_errprintn(MSG) 196 # ----------------- 197 # Same as `errprint', but with the missing end of line. 198 m4_define([m4_errprintn], 199 [m4_errprint([$1 200 ])]) 201 202 203 # m4_warning(MSG) 204 # --------------- 205 # Warn the user. 206 m4_define([m4_warning], 207 [m4_errprintn(m4_location[: warning: $1])]) 208 209 210 # m4_fatal(MSG, [EXIT-STATUS]) 211 # ---------------------------- 212 # Fatal the user. :) 213 m4_define([m4_fatal], 214 [m4_errprintn(m4_location[: error: $1] 215 m4_expansion_stack)m4_exit(m4_if([$2],, 1, [$2]))]) 216 217 218 # m4_assert(EXPRESSION, [EXIT-STATUS = 1]) 219 # ---------------------------------------- 220 # This macro ensures that EXPRESSION evaluates to true, and exits if 221 # EXPRESSION evaluates to false. 222 m4_define([m4_assert], 223 [m4_if(m4_eval([$1]), 0, 224 [m4_fatal([assert failed: $1], [$2])])]) 225 226 227 228 ## ------------- ## 229 ## 3. Warnings. ## 230 ## ------------- ## 231 232 233 # _m4_warn(CATEGORY, MESSAGE, [STACK-TRACE]) 234 # ------------------------------------------ 235 # Report a MESSAGE to the user if the CATEGORY of warnings is enabled. 236 # This is for traces only. 237 # If present, STACK-TRACE is a \n-separated list of "LOCATION: MESSAGE", 238 # where the last line (and no other) ends with "the top level". 239 # 240 # Within m4, the macro is a no-op. This macro really matters 241 # when autom4te post-processes the trace output. 242 m4_define([_m4_warn], []) 243 244 245 # m4_warn(CATEGORY, MESSAGE) 246 # -------------------------- 247 # Report a MESSAGE to the user if the CATEGORY of warnings is enabled. 248 m4_define([m4_warn], 249 [_m4_warn([$1], [$2], 250 m4_ifdef([_m4_expansion_stack], [m4_expansion_stack]))]) 251 252 253 254 ## ------------------- ## 255 ## 4. File inclusion. ## 256 ## ------------------- ## 257 258 259 # We also want to neutralize include (and sinclude for symmetry), 260 # but we want to extend them slightly: warn when a file is included 261 # several times. This is, in general, a dangerous operation, because 262 # too many people forget to quote the first argument of m4_define. 263 # 264 # For instance in the following case: 265 # m4_define(foo, [bar]) 266 # then a second reading will turn into 267 # m4_define(bar, [bar]) 268 # which is certainly not what was meant. 269 270 # m4_include_unique(FILE) 271 # ----------------------- 272 # Declare that the FILE was loading; and warn if it has already 273 # been included. 274 m4_define([m4_include_unique], 275 [m4_ifdef([m4_include($1)], 276 [m4_warn([syntax], [file `$1' included several times])])dnl 277 m4_define([m4_include($1)])]) 278 279 280 # m4_include(FILE) 281 # ---------------- 282 # Like the builtin include, but warns against multiple inclusions. 283 m4_define([m4_include], 284 [m4_include_unique([$1])dnl 285 m4_builtin([include], [$1])]) 286 287 288 # m4_sinclude(FILE) 289 # ----------------- 290 # Like the builtin sinclude, but warns against multiple inclusions. 291 m4_define([m4_sinclude], 292 [m4_include_unique([$1])dnl 293 m4_builtin([sinclude], [$1])]) 294 295 296 297 ## ------------------------------------ ## 298 ## 5. Additional branching constructs. ## 299 ## ------------------------------------ ## 300 301 # Both `m4_ifval' and `m4_ifset' tests against the empty string. The 302 # difference is that `m4_ifset' is specialized on macros. 303 # 304 # In case of arguments of macros, eg. $1, it makes little difference. 305 # In the case of a macro `FOO', you don't want to check `m4_ifval(FOO, 306 # TRUE)', because if `FOO' expands with commas, there is a shifting of 307 # the arguments. So you want to run `m4_ifval([FOO])', but then you just 308 # compare the *string* `FOO' against `', which, of course fails. 309 # 310 # So you want the variation `m4_ifset' that expects a macro name as $1. 311 # If this macro is both defined and defined to a non empty value, then 312 # it runs TRUE, etc. 313 314 315 # m4_ifblank(COND, [IF-BLANK], [IF-TEXT]) 316 # m4_ifnblank(COND, [IF-TEXT], [IF-BLANK]) 317 # ---------------------------------------- 318 # If COND is empty, or consists only of blanks (space, tab, newline), 319 # then expand IF-BLANK, otherwise expand IF-TEXT. This differs from 320 # m4_ifval only if COND has just whitespace, but it helps optimize in 321 # spite of users who mistakenly leave trailing space after what they 322 # thought was an empty argument: 323 # macro( 324 # [] 325 # ) 326 # 327 # Writing one macro in terms of the other causes extra overhead, so 328 # we inline both definitions. 329 m4_define([m4_ifblank], 330 [m4_if(m4_translit([[$1]], [ ][ ][ 331 ]), [], [$2], [$3])]) 332 333 m4_define([m4_ifnblank], 334 [m4_if(m4_translit([[$1]], [ ][ ][ 335 ]), [], [$3], [$2])]) 336 337 338 # m4_ifval(COND, [IF-TRUE], [IF-FALSE]) 339 # ------------------------------------- 340 # If COND is not the empty string, expand IF-TRUE, otherwise IF-FALSE. 341 # Comparable to m4_ifdef. 342 m4_define([m4_ifval], 343 [m4_if([$1], [], [$3], [$2])]) 344 345 346 # m4_n(TEXT) 347 # ---------- 348 # If TEXT is not empty, return TEXT and a new line, otherwise nothing. 349 m4_define([m4_n], 350 [m4_if([$1], 351 [], [], 352 [$1 353 ])]) 354 355 356 # m4_ifvaln(COND, [IF-TRUE], [IF-FALSE]) 357 # -------------------------------------- 358 # Same as `m4_ifval', but add an extra newline to IF-TRUE or IF-FALSE 359 # unless that argument is empty. 360 m4_define([m4_ifvaln], 361 [m4_if([$1], 362 [], [m4_n([$3])], 363 [m4_n([$2])])]) 364 365 366 # m4_ifset(MACRO, [IF-TRUE], [IF-FALSE]) 367 # -------------------------------------- 368 # If MACRO has no definition, or of its definition is the empty string, 369 # expand IF-FALSE, otherwise IF-TRUE. 370 m4_define([m4_ifset], 371 [m4_ifdef([$1], 372 [m4_ifval(_m4_defn([$1]), [$2], [$3])], 373 [$3])]) 374 375 376 # m4_ifndef(NAME, [IF-NOT-DEFINED], [IF-DEFINED]) 377 # ----------------------------------------------- 378 m4_define([m4_ifndef], 379 [m4_ifdef([$1], [$3], [$2])]) 380 381 382 # m4_case(SWITCH, VAL1, IF-VAL1, VAL2, IF-VAL2, ..., DEFAULT) 383 # ----------------------------------------------------------- 384 # m4 equivalent of 385 # switch (SWITCH) 386 # { 387 # case VAL1: 388 # IF-VAL1; 389 # break; 390 # case VAL2: 391 # IF-VAL2; 392 # break; 393 # ... 394 # default: 395 # DEFAULT; 396 # break; 397 # }. 398 # All the values are optional, and the macro is robust to active 399 # symbols properly quoted. 400 # 401 # Please keep foreach.m4 in sync with any adjustments made here. 402 m4_define([m4_case], 403 [m4_if([$#], 0, [], 404 [$#], 1, [], 405 [$#], 2, [$2], 406 [$1], [$2], [$3], 407 [$0([$1], m4_shift3($@))])]) 408 409 410 # m4_bmatch(SWITCH, RE1, VAL1, RE2, VAL2, ..., DEFAULT) 411 # ----------------------------------------------------- 412 # m4 equivalent of 413 # 414 # if (SWITCH =~ RE1) 415 # VAL1; 416 # elif (SWITCH =~ RE2) 417 # VAL2; 418 # elif ... 419 # ... 420 # else 421 # DEFAULT 422 # 423 # All the values are optional, and the macro is robust to active symbols 424 # properly quoted. 425 # 426 # Please keep foreach.m4 in sync with any adjustments made here. 427 m4_define([m4_bmatch], 428 [m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], 429 [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], 430 [$#], 2, [$2], 431 [m4_if(m4_bregexp([$1], [$2]), -1, [$0([$1], m4_shift3($@))], 432 [$3])])]) 433 434 # m4_argn(N, ARGS...) 435 # ------------------- 436 # Extract argument N (greater than 0) from ARGS. Example: 437 # m4_define([b], [B]) 438 # m4_argn([2], [a], [b], [c]) => b 439 # 440 # Rather than using m4_car(m4_shiftn([$1], $@)), we exploit the fact that 441 # GNU m4 can directly reference any argument, through an indirect macro. 442 m4_define([m4_argn], 443 [m4_assert([0 < $1])]dnl 444 [m4_pushdef([_$0], [_m4_popdef([_$0])]m4_dquote([$]m4_incr([$1])))_$0($@)]) 445 446 447 # m4_car(ARGS...) 448 # m4_cdr(ARGS...) 449 # --------------- 450 # Manipulate m4 lists. m4_car returns the first argument. m4_cdr 451 # bundles all but the first argument into a quoted list. These two 452 # macros are generally used with list arguments, with quoting removed 453 # to break the list into multiple m4 ARGS. 454 m4_define([m4_car], [[$1]]) 455 m4_define([m4_cdr], 456 [m4_if([$#], 0, [m4_fatal([$0: cannot be called without arguments])], 457 [$#], 1, [], 458 [m4_dquote(m4_shift($@))])]) 459 460 # _m4_cdr(ARGS...) 461 # ---------------- 462 # Like m4_cdr, except include a leading comma unless only one argument 463 # remains. Why? Because comparing a large list against [] is more 464 # expensive in expansion time than comparing the number of arguments; so 465 # _m4_cdr can be used to reduce the number of arguments when it is time 466 # to end recursion. 467 m4_define([_m4_cdr], 468 [m4_if([$#], 1, [], 469 [, m4_dquote(m4_shift($@))])]) 470 471 472 473 # m4_cond(TEST1, VAL1, IF-VAL1, TEST2, VAL2, IF-VAL2, ..., [DEFAULT]) 474 # ------------------------------------------------------------------- 475 # Similar to m4_if, except that each TEST is expanded when encountered. 476 # If the expansion of TESTn matches the string VALn, the result is IF-VALn. 477 # The result is DEFAULT if no tests passed. This macro allows 478 # short-circuiting of expensive tests, where it pays to arrange quick 479 # filter tests to run first. 480 # 481 # For an example, consider a previous implementation of _AS_QUOTE_IFELSE: 482 # 483 # m4_if(m4_index([$1], [\]), [-1], [$2], 484 # m4_eval(m4_index([$1], [\\]) >= 0), [1], [$2], 485 # m4_eval(m4_index([$1], [\$]) >= 0), [1], [$2], 486 # m4_eval(m4_index([$1], [\`]) >= 0), [1], [$3], 487 # m4_eval(m4_index([$1], [\"]) >= 0), [1], [$3], 488 # [$2]) 489 # 490 # Here, m4_index is computed 5 times, and m4_eval 4, even if $1 contains 491 # no backslash. It is more efficient to do: 492 # 493 # m4_cond([m4_index([$1], [\])], [-1], [$2], 494 # [m4_eval(m4_index([$1], [\\]) >= 0)], [1], [$2], 495 # [m4_eval(m4_index([$1], [\$]) >= 0)], [1], [$2], 496 # [m4_eval(m4_index([$1], [\`]) >= 0)], [1], [$3], 497 # [m4_eval(m4_index([$1], [\"]) >= 0)], [1], [$3], 498 # [$2]) 499 # 500 # In the common case of $1 with no backslash, only one m4_index expansion 501 # occurs, and m4_eval is avoided altogether. 502 # 503 # Please keep foreach.m4 in sync with any adjustments made here. 504 m4_define([m4_cond], 505 [m4_if([$#], [0], [m4_fatal([$0: cannot be called without arguments])], 506 [$#], [1], [$1], 507 m4_eval([$# % 3]), [2], [m4_fatal([$0: missing an argument])], 508 [_$0($@)])]) 509 510 m4_define([_m4_cond], 511 [m4_if(($1), [($2)], [$3], 512 [$#], [3], [], 513 [$#], [4], [$4], 514 [$0(m4_shift3($@))])]) 515 516 517 ## ---------------------------------------- ## 518 ## 6. Enhanced version of some primitives. ## 519 ## ---------------------------------------- ## 520 521 # m4_bpatsubsts(STRING, RE1, SUBST1, RE2, SUBST2, ...) 522 # ---------------------------------------------------- 523 # m4 equivalent of 524 # 525 # $_ = STRING; 526 # s/RE1/SUBST1/g; 527 # s/RE2/SUBST2/g; 528 # ... 529 # 530 # All the values are optional, and the macro is robust to active symbols 531 # properly quoted. 532 # 533 # I would have liked to name this macro `m4_bpatsubst', unfortunately, 534 # due to quotation problems, I need to double quote $1 below, therefore 535 # the anchors are broken :( I can't let users be trapped by that. 536 # 537 # Recall that m4_shift3 always results in an argument. Hence, we need 538 # to distinguish between a final deletion vs. ending recursion. 539 # 540 # Please keep foreach.m4 in sync with any adjustments made here. 541 m4_define([m4_bpatsubsts], 542 [m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], 543 [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], 544 [$#], 2, [m4_unquote(m4_builtin([patsubst], [[$1]], [$2]))], 545 [$#], 3, [m4_unquote(m4_builtin([patsubst], [[$1]], [$2], [$3]))], 546 [_$0($@m4_if(m4_eval($# & 1), 0, [,]))])]) 547 m4_define([_m4_bpatsubsts], 548 [m4_if([$#], 2, [$1], 549 [$0(m4_builtin([patsubst], [[$1]], [$2], [$3]), 550 m4_shift3($@))])]) 551 552 553 # m4_copy(SRC, DST) 554 # ----------------- 555 # Define the pushdef stack DST as a copy of the pushdef stack SRC; 556 # give an error if DST is already defined. This is particularly nice 557 # for copying self-modifying pushdef stacks, where the top definition 558 # includes one-shot initialization that is later popped to the normal 559 # definition. This version intentionally does nothing if SRC is 560 # undefined. 561 # 562 # Some macros simply can't be renamed with this method: namely, anything 563 # involved in the implementation of m4_stack_foreach_sep. 564 m4_define([m4_copy], 565 [m4_ifdef([$2], [m4_fatal([$0: won't overwrite defined macro: $2])], 566 [m4_stack_foreach_sep([$1], [m4_pushdef([$2],], [)])])]dnl 567 [m4_ifdef([m4_location($1)], [m4_define([m4_location($2)], m4_location)])]) 568 569 570 # m4_copy_force(SRC, DST) 571 # m4_rename_force(SRC, DST) 572 # ------------------------- 573 # Like m4_copy/m4_rename, except blindly overwrite any existing DST. 574 # Note that m4_copy_force tolerates undefined SRC, while m4_rename_force 575 # does not. 576 m4_define([m4_copy_force], 577 [m4_ifdef([$2], [_m4_undefine([$2])])m4_copy($@)]) 578 579 m4_define([m4_rename_force], 580 [m4_ifdef([$2], [_m4_undefine([$2])])m4_rename($@)]) 581 582 583 # m4_define_default(MACRO, VALUE) 584 # ------------------------------- 585 # If MACRO is undefined, set it to VALUE. 586 m4_define([m4_define_default], 587 [m4_ifndef([$1], [m4_define($@)])]) 588 589 590 # m4_default(EXP1, EXP2) 591 # m4_default_nblank(EXP1, EXP2) 592 # ----------------------------- 593 # Returns EXP1 if not empty/blank, otherwise EXP2. Expand the result. 594 # 595 # m4_default is called on hot paths, so inline the contents of m4_ifval, 596 # for one less round of expansion. 597 m4_define([m4_default], 598 [m4_if([$1], [], [$2], [$1])]) 599 600 m4_define([m4_default_nblank], 601 [m4_ifblank([$1], [$2], [$1])]) 602 603 604 # m4_default_quoted(EXP1, EXP2) 605 # m4_default_nblank_quoted(EXP1, EXP2) 606 # ------------------------------------ 607 # Returns EXP1 if non empty/blank, otherwise EXP2. Leave the result quoted. 608 # 609 # For comparison: 610 # m4_define([active], [ACTIVE]) 611 # m4_default([active], [default]) => ACTIVE 612 # m4_default([], [active]) => ACTIVE 613 # -m4_default([ ], [active])- => - - 614 # -m4_default_nblank([ ], [active])- => -ACTIVE- 615 # m4_default_quoted([active], [default]) => active 616 # m4_default_quoted([], [active]) => active 617 # -m4_default_quoted([ ], [active])- => - - 618 # -m4_default_nblank_quoted([ ], [active])- => -active- 619 # 620 # m4_default macro is called on hot paths, so inline the contents of m4_ifval, 621 # for one less round of expansion. 622 m4_define([m4_default_quoted], 623 [m4_if([$1], [], [[$2]], [[$1]])]) 624 625 m4_define([m4_default_nblank_quoted], 626 [m4_ifblank([$1], [[$2]], [[$1]])]) 627 628 629 # m4_defn(NAME) 630 # ------------- 631 # Like the original, except guarantee a warning when using something which is 632 # undefined (unlike M4 1.4.x). This replacement is not a full-featured 633 # replacement: if any of the defined macros contain unbalanced quoting, but 634 # when pasted together result in a well-quoted string, then only native m4 635 # support is able to get it correct. But that's where quadrigraphs come in 636 # handy, if you really need unbalanced quotes inside your macros. 637 # 638 # This macro is called frequently, so minimize the amount of additional 639 # expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, 640 # (added in M4 1.6), then let m4 do the job for us (see m4_init). 641 m4_define([m4_defn], 642 [m4_if([$#], [0], [[$0]], 643 [$#], [1], [m4_ifdef([$1], [_m4_defn([$1])], 644 [m4_fatal([$0: undefined macro: $1])])], 645 [m4_map_args([$0], $@)])]) 646 647 648 # m4_dumpdef(NAME...) 649 # ------------------- 650 # In m4 1.4.x, dumpdef writes to the current debugfile, rather than 651 # stderr. This in turn royally confuses autom4te; so we follow the 652 # lead of newer m4 and always dump to stderr. Unlike the original, 653 # this version requires an argument, since there is no convenient way 654 # in m4 1.4.x to grab the names of all defined macros. Newer m4 655 # always dumps to stderr, regardless of the current debugfile; it also 656 # provides m4symbols as a way to grab all current macro names. But 657 # dumpdefs is not frequently called, so we don't need to worry about 658 # conditionally using these newer features. Also, this version 659 # doesn't sort multiple arguments. 660 # 661 # If we detect m4 1.6 or newer, then provide an alternate definition, 662 # installed during m4_init, that allows builtins through. 663 # Unfortunately, there is no nice way in m4 1.4.x to dump builtins. 664 m4_define([m4_dumpdef], 665 [m4_if([$#], [0], [m4_fatal([$0: missing argument])], 666 [$#], [1], [m4_ifdef([$1], [m4_errprintn( 667 [$1: ]m4_dquote(_m4_defn([$1])))], [m4_fatal([$0: undefined macro: $1])])], 668 [m4_map_args([$0], $@)])]) 669 670 m4_define([_m4_dumpdef], 671 [m4_if([$#], [0], [m4_fatal([$0: missing argument])], 672 [$#], [1], [m4_builtin([dumpdef], [$1])], 673 [m4_map_args_sep([m4_builtin([dumpdef],], [)], [], $@)])]) 674 675 676 # m4_dumpdefs(NAME...) 677 # -------------------- 678 # Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its 679 # value stack (most recent displayed first). Also, this version silently 680 # ignores undefined macros, rather than erroring out. 681 # 682 # This macro cheats, because it relies on the current definition of NAME 683 # while the second argument of m4_stack_foreach_lifo is evaluated (which 684 # would be undefined according to the API). 685 m4_define([m4_dumpdefs], 686 [m4_if([$#], [0], [m4_fatal([$0: missing argument])], 687 [$#], [1], [m4_stack_foreach_lifo([$1], [m4_dumpdef([$1])m4_ignore])], 688 [m4_map_args([$0], $@)])]) 689 690 # m4_esyscmd_s(COMMAND) 691 # --------------------- 692 # Like m4_esyscmd, except strip any trailing newlines, thus behaving 693 # more like shell command substitution. 694 m4_define([m4_esyscmd_s], 695 [m4_chomp_all(m4_esyscmd([$1]))]) 696 697 698 # m4_popdef(NAME) 699 # --------------- 700 # Like the original, except guarantee a warning when using something which is 701 # undefined (unlike M4 1.4.x). 702 # 703 # This macro is called frequently, so minimize the amount of additional 704 # expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, 705 # (added in M4 1.6), then let m4 do the job for us (see m4_init). 706 m4_define([m4_popdef], 707 [m4_if([$#], [0], [[$0]], 708 [$#], [1], [m4_ifdef([$1], [_m4_popdef([$1])], 709 [m4_fatal([$0: undefined macro: $1])])], 710 [m4_map_args([$0], $@)])]) 711 712 713 # m4_shiftn(N, ...) 714 # ----------------- 715 # Returns ... shifted N times. Useful for recursive "varargs" constructs. 716 # 717 # Autoconf does not use this macro, because it is inherently slower than 718 # calling the common cases of m4_shift2 or m4_shift3 directly. But it 719 # might as well be fast for other clients, such as Libtool. One way to 720 # do this is to expand $@ only once in _m4_shiftn (otherwise, for long 721 # lists, the expansion of m4_if takes twice as much memory as what the 722 # list itself occupies, only to throw away the unused branch). The end 723 # result is strictly equivalent to 724 # m4_if([$1], 1, [m4_shift(,m4_shift(m4_shift($@)))], 725 # [_m4_shiftn(m4_decr([$1]), m4_shift(m4_shift($@)))]) 726 # but with the final `m4_shift(m4_shift($@)))' shared between the two 727 # paths. The first leg uses a no-op m4_shift(,$@) to balance out the (). 728 # 729 # Please keep foreach.m4 in sync with any adjustments made here. 730 m4_define([m4_shiftn], 731 [m4_assert(0 < $1 && $1 < $#)_$0($@)]) 732 733 m4_define([_m4_shiftn], 734 [m4_if([$1], 1, [m4_shift(], 735 [$0(m4_decr([$1])]), m4_shift(m4_shift($@)))]) 736 737 # m4_shift2(...) 738 # m4_shift3(...) 739 # -------------- 740 # Returns ... shifted twice, and three times. Faster than m4_shiftn. 741 m4_define([m4_shift2], [m4_shift(m4_shift($@))]) 742 m4_define([m4_shift3], [m4_shift(m4_shift(m4_shift($@)))]) 743 744 # _m4_shift2(...) 745 # _m4_shift3(...) 746 # --------------- 747 # Like m4_shift2 or m4_shift3, except include a leading comma unless shifting 748 # consumes all arguments. Why? Because in recursion, it is nice to 749 # distinguish between 1 element left and 0 elements left, based on how many 750 # arguments this shift expands to. 751 m4_define([_m4_shift2], 752 [m4_if([$#], [2], [], 753 [, m4_shift(m4_shift($@))])]) 754 m4_define([_m4_shift3], 755 [m4_if([$#], [3], [], 756 [, m4_shift(m4_shift(m4_shift($@)))])]) 757 758 759 # m4_undefine(NAME) 760 # ----------------- 761 # Like the original, except guarantee a warning when using something which is 762 # undefined (unlike M4 1.4.x). 763 # 764 # This macro is called frequently, so minimize the amount of additional 765 # expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, 766 # (added in M4 1.6), then let m4 do the job for us (see m4_init). 767 m4_define([m4_undefine], 768 [m4_if([$#], [0], [[$0]], 769 [$#], [1], [m4_ifdef([$1], [_m4_undefine([$1])], 770 [m4_fatal([$0: undefined macro: $1])])], 771 [m4_map_args([$0], $@)])]) 772 773 # _m4_wrap(PRE, POST) 774 # ------------------- 775 # Helper macro for m4_wrap and m4_wrap_lifo. Allows nested calls to 776 # m4_wrap within wrapped text. Use _m4_defn and _m4_popdef for speed. 777 m4_define([_m4_wrap], 778 [m4_ifdef([$0_text], 779 [m4_define([$0_text], [$1]_m4_defn([$0_text])[$2])], 780 [m4_builtin([m4wrap], [m4_unquote( 781 _m4_defn([$0_text])_m4_popdef([$0_text]))])m4_define([$0_text], [$1$2])])]) 782 783 # m4_wrap(TEXT) 784 # ------------- 785 # Append TEXT to the list of hooks to be executed at the end of input. 786 # Whereas the order of the original may be LIFO in the underlying m4, 787 # this version is always FIFO. 788 m4_define([m4_wrap], 789 [_m4_wrap([], [$1[]])]) 790 791 # m4_wrap_lifo(TEXT) 792 # ------------------ 793 # Prepend TEXT to the list of hooks to be executed at the end of input. 794 # Whereas the order of m4_wrap may be FIFO in the underlying m4, this 795 # version is always LIFO. 796 m4_define([m4_wrap_lifo], 797 [_m4_wrap([$1[]])]) 798 799 ## ------------------------- ## 800 ## 7. Quoting manipulation. ## 801 ## ------------------------- ## 802 803 804 # m4_apply(MACRO, LIST) 805 # --------------------- 806 # Invoke MACRO, with arguments provided from the quoted list of 807 # comma-separated quoted arguments. If LIST is empty, invoke MACRO 808 # without arguments. The expansion will not be concatenated with 809 # subsequent text. 810 m4_define([m4_apply], 811 [m4_if([$2], [], [$1], [$1($2)])[]]) 812 813 # _m4_apply(MACRO, LIST) 814 # ---------------------- 815 # Like m4_apply, except do nothing if LIST is empty. 816 m4_define([_m4_apply], 817 [m4_if([$2], [], [], [$1($2)[]])]) 818 819 820 # m4_count(ARGS) 821 # -------------- 822 # Return a count of how many ARGS are present. 823 m4_define([m4_count], [$#]) 824 825 826 # m4_curry(MACRO, ARG...) 827 # ----------------------- 828 # Perform argument currying. The expansion of this macro is another 829 # macro that takes exactly one argument, appends it to the end of the 830 # original ARG list, then invokes MACRO. For example: 831 # m4_curry([m4_curry], [m4_reverse], [1])([2])([3]) => 3, 2, 1 832 # Not quite as practical as m4_incr, but you could also do: 833 # m4_define([add], [m4_eval(([$1]) + ([$2]))]) 834 # m4_define([add_one], [m4_curry([add], [1])]) 835 # add_one()([2]) => 3 836 m4_define([m4_curry], [$1(m4_shift($@,)_$0]) 837 m4_define([_m4_curry], [[$1])]) 838 839 840 # m4_do(STRING, ...) 841 # ------------------ 842 # This macro invokes all its arguments (in sequence, of course). It is 843 # useful for making your macros more structured and readable by dropping 844 # unnecessary dnl's and have the macros indented properly. No concatenation 845 # occurs after a STRING; use m4_unquote(m4_join(,STRING)) for that. 846 # 847 # Please keep foreach.m4 in sync with any adjustments made here. 848 m4_define([m4_do], 849 [m4_if([$#], 0, [], 850 [$#], 1, [$1[]], 851 [$1[]$0(m4_shift($@))])]) 852 853 854 # m4_dquote(ARGS) 855 # --------------- 856 # Return ARGS as a quoted list of quoted arguments. 857 m4_define([m4_dquote], [[$@]]) 858 859 860 # m4_dquote_elt(ARGS) 861 # ------------------- 862 # Return ARGS as an unquoted list of double-quoted arguments. 863 # 864 # Please keep foreach.m4 in sync with any adjustments made here. 865 m4_define([m4_dquote_elt], 866 [m4_if([$#], [0], [], 867 [$#], [1], [[[$1]]], 868 [[[$1]],$0(m4_shift($@))])]) 869 870 871 # m4_echo(ARGS) 872 # ------------- 873 # Return the ARGS, with the same level of quoting. Whitespace after 874 # unquoted commas are consumed. 875 m4_define([m4_echo], [$@]) 876 877 878 # m4_expand(ARG) 879 # _m4_expand(ARG) 880 # --------------- 881 # Return the expansion of ARG as a single string. Unlike 882 # m4_quote($1), this preserves whitespace following single-quoted 883 # commas that appear within ARG. It also deals with shell case 884 # statements. 885 # 886 # m4_define([active], [ACT, IVE]) 887 # m4_define([active2], [[ACT, IVE]]) 888 # m4_quote(active, active2) 889 # => ACT,IVE,ACT, IVE 890 # m4_expand([active, active2]) 891 # => ACT, IVE, ACT, IVE 892 # 893 # Unfortunately, due to limitations in m4, ARG must expand to 894 # something with balanced quotes (use quadrigraphs to get around 895 # this), and should not contain the unlikely delimiters -=<{( or 896 # )}>=-. It is possible to have unbalanced quoted `(' or `)', as well 897 # as unbalanced unquoted `)'. m4_expand can handle unterminated 898 # comments or dnl on the final line, at the expense of speed; it also 899 # aids in detecting attempts to incorrectly change the current 900 # diversion inside ARG. Meanwhile, _m4_expand is faster but must be 901 # given a terminated expansion, and has no safety checks for 902 # mis-diverted text. 903 # 904 # Exploit that extra unquoted () will group unquoted commas and the 905 # following whitespace. m4_bpatsubst can't handle newlines inside $1, 906 # and m4_substr strips quoting. So we (ab)use m4_changequote, using 907 # temporary quotes to remove the delimiters that conveniently included 908 # the unquoted () that were added prior to the changequote. 909 # 910 # Thanks to shell case statements, too many people are prone to pass 911 # underquoted `)', so we try to detect that by passing a marker as a 912 # fourth argument; if the marker is not present, then we assume that 913 # we encountered an early `)', and re-expand the first argument, but 914 # this time with one more `(' in the second argument and in the 915 # open-quote delimiter. We must also ignore the slop from the 916 # previous try. The final macro is thus half line-noise, half art. 917 m4_define([m4_expand], 918 [m4_pushdef([m4_divert], _m4_defn([_m4_divert_unsafe]))]dnl 919 [m4_pushdef([m4_divert_push], _m4_defn([_m4_divert_unsafe]))]dnl 920 [m4_chomp(_$0([$1 921 ]))_m4_popdef([m4_divert], [m4_divert_push])]) 922 923 m4_define([_m4_expand], [$0_([$1], [(], -=<{($1)}>=-, [}>=-])]) 924 925 m4_define([_m4_expand_], 926 [m4_if([$4], [}>=-], 927 [m4_changequote([-=<{$2], [)}>=-])$3m4_changequote([, ])], 928 [$0([$1], [($2], -=<{($2$1)}>=-, [}>=-])m4_ignore$2])]) 929 930 931 # m4_ignore(ARGS) 932 # --------------- 933 # Expands to nothing. Useful for conditionally ignoring an arbitrary 934 # number of arguments (see _m4_list_cmp for an example). 935 m4_define([m4_ignore]) 936 937 938 # m4_make_list(ARGS) 939 # ------------------ 940 # Similar to m4_dquote, this creates a quoted list of quoted ARGS. This 941 # version is less efficient than m4_dquote, but separates each argument 942 # with a comma and newline, rather than just comma, for readability. 943 # When developing an m4sugar algorithm, you could temporarily use 944 # m4_pushdef([m4_dquote],m4_defn([m4_make_list])) 945 # around your code to make debugging easier. 946 m4_define([m4_make_list], [m4_join([, 947 ], m4_dquote_elt($@))]) 948 949 950 # m4_noquote(STRING) 951 # ------------------ 952 # Return the result of ignoring all quotes in STRING and invoking the 953 # macros it contains. Among other things, this is useful for enabling 954 # macro invocations inside strings with [] blocks (for instance regexps 955 # and help-strings). On the other hand, since all quotes are disabled, 956 # any macro expanded during this time that relies on nested [] quoting 957 # will likely crash and burn. This macro is seldom useful; consider 958 # m4_unquote or m4_expand instead. 959 m4_define([m4_noquote], 960 [m4_changequote([-=<{(],[)}>=-])$1-=<{()}>=-m4_changequote([,])]) 961 962 963 # m4_quote(ARGS) 964 # -------------- 965 # Return ARGS as a single argument. Any whitespace after unquoted commas 966 # is stripped. There is always output, even when there were no arguments. 967 # 968 # It is important to realize the difference between `m4_quote(exp)' and 969 # `[exp]': in the first case you obtain the quoted *result* of the 970 # expansion of EXP, while in the latter you just obtain the string 971 # `exp'. 972 m4_define([m4_quote], [[$*]]) 973 974 975 # _m4_quote(ARGS) 976 # --------------- 977 # Like m4_quote, except that when there are no arguments, there is no 978 # output. For conditional scenarios (such as passing _m4_quote as the 979 # macro name in m4_mapall), this feature can be used to distinguish between 980 # one argument of the empty string vs. no arguments. However, in the 981 # normal case with arguments present, this is less efficient than m4_quote. 982 m4_define([_m4_quote], 983 [m4_if([$#], [0], [], [[$*]])]) 984 985 986 # m4_reverse(ARGS) 987 # ---------------- 988 # Output ARGS in reverse order. 989 # 990 # Please keep foreach.m4 in sync with any adjustments made here. 991 m4_define([m4_reverse], 992 [m4_if([$#], [0], [], [$#], [1], [[$1]], 993 [$0(m4_shift($@)), [$1]])]) 994 995 996 # m4_unquote(ARGS) 997 # ---------------- 998 # Remove one layer of quotes from each ARG, performing one level of 999 # expansion. For one argument, m4_unquote([arg]) is more efficient than 1000 # m4_do([arg]), but for multiple arguments, the difference is that 1001 # m4_unquote separates arguments with commas while m4_do concatenates. 1002 # Follow this macro with [] if concatenation with subsequent text is 1003 # undesired. 1004 m4_define([m4_unquote], [$*]) 1005 1006 1007 ## -------------------------- ## 1008 ## 8. Implementing m4 loops. ## 1009 ## -------------------------- ## 1010 1011 1012 # m4_for(VARIABLE, FIRST, LAST, [STEP = +/-1], EXPRESSION) 1013 # -------------------------------------------------------- 1014 # Expand EXPRESSION defining VARIABLE to FROM, FROM + 1, ..., TO with 1015 # increments of STEP. Both limits are included, and bounds are 1016 # checked for consistency. The algorithm is robust to indirect 1017 # VARIABLE names. Changing VARIABLE inside EXPRESSION will not impact 1018 # the number of iterations. 1019 # 1020 # Uses _m4_defn for speed, and avoid dnl in the macro body. Factor 1021 # the _m4_for call so that EXPRESSION is only parsed once. 1022 m4_define([m4_for], 1023 [m4_pushdef([$1], m4_eval([$2]))]dnl 1024 [m4_cond([m4_eval(([$3]) > ([$2]))], 1, 1025 [m4_pushdef([_m4_step], m4_eval(m4_default_quoted([$4], 1026 1)))m4_assert(_m4_step > 0)_$0(_m4_defn([$1]), 1027 m4_eval((([$3]) - ([$2])) / _m4_step * _m4_step + ([$2])), _m4_step,], 1028 [m4_eval(([$3]) < ([$2]))], 1, 1029 [m4_pushdef([_m4_step], m4_eval(m4_default_quoted([$4], 1030 -1)))m4_assert(_m4_step < 0)_$0(_m4_defn([$1]), 1031 m4_eval((([$2]) - ([$3])) / -(_m4_step) * _m4_step + ([$2])), _m4_step,], 1032 [m4_pushdef([_m4_step])_$0(_m4_defn([$1]), _m4_defn([$1]), 0,])]dnl 1033 [[m4_define([$1],], [)$5])m4_popdef([_m4_step], [$1])]) 1034 1035 # _m4_for(COUNT, LAST, STEP, PRE, POST) 1036 # ------------------------------------- 1037 # Core of the loop, no consistency checks, all arguments are plain 1038 # numbers. Expand PRE[COUNT]POST, then alter COUNT by STEP and 1039 # iterate if COUNT is not LAST. 1040 m4_define([_m4_for], 1041 [$4[$1]$5[]m4_if([$1], [$2], [], 1042 [$0(m4_eval([$1 + $3]), [$2], [$3], [$4], [$5])])]) 1043 1044 1045 # Implementing `foreach' loops in m4 is much more tricky than it may 1046 # seem. For example, the old M4 1.4.4 manual had an incorrect example, 1047 # which looked like this (when translated to m4sugar): 1048 # 1049 # | # foreach(VAR, (LIST), STMT) 1050 # | m4_define([foreach], 1051 # | [m4_pushdef([$1])_foreach([$1], [$2], [$3])m4_popdef([$1])]) 1052 # | m4_define([_arg1], [$1]) 1053 # | m4_define([_foreach], 1054 # | [m4_if([$2], [()], , 1055 # | [m4_define([$1], _arg1$2)$3[]_foreach([$1], (m4_shift$2), [$3])])]) 1056 # 1057 # But then if you run 1058 # 1059 # | m4_define(a, 1) 1060 # | m4_define(b, 2) 1061 # | m4_define(c, 3) 1062 # | foreach([f], [([a], [(b], [c)])], [echo f 1063 # | ]) 1064 # 1065 # it gives 1066 # 1067 # => echo 1 1068 # => echo (2,3) 1069 # 1070 # which is not what is expected. 1071 # 1072 # Of course the problem is that many quotes are missing. So you add 1073 # plenty of quotes at random places, until you reach the expected 1074 # result. Alternatively, if you are a quoting wizard, you directly 1075 # reach the following implementation (but if you really did, then 1076 # apply to the maintenance of m4sugar!). 1077 # 1078 # | # foreach(VAR, (LIST), STMT) 1079 # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])]) 1080 # | m4_define([_arg1], [[$1]]) 1081 # | m4_define([_foreach], 1082 # | [m4_if($2, [()], , 1083 # | [m4_define([$1], [_arg1$2])$3[]_foreach([$1], [(m4_shift$2)], [$3])])]) 1084 # 1085 # which this time answers 1086 # 1087 # => echo a 1088 # => echo (b 1089 # => echo c) 1090 # 1091 # Bingo! 1092 # 1093 # Well, not quite. 1094 # 1095 # With a better look, you realize that the parens are more a pain than 1096 # a help: since anyway you need to quote properly the list, you end up 1097 # with always using an outermost pair of parens and an outermost pair 1098 # of quotes. Rejecting the parens both eases the implementation, and 1099 # simplifies the use: 1100 # 1101 # | # foreach(VAR, (LIST), STMT) 1102 # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])]) 1103 # | m4_define([_arg1], [$1]) 1104 # | m4_define([_foreach], 1105 # | [m4_if($2, [], , 1106 # | [m4_define([$1], [_arg1($2)])$3[]_foreach([$1], [m4_shift($2)], [$3])])]) 1107 # 1108 # 1109 # Now, just replace the `$2' with `m4_quote($2)' in the outer `m4_if' 1110 # to improve robustness, and you come up with a nice implementation 1111 # that doesn't require extra parentheses in the user's LIST. 1112 # 1113 # But wait - now the algorithm is quadratic, because every recursion of 1114 # the algorithm keeps the entire LIST and merely adds another m4_shift to 1115 # the quoted text. If the user has a lot of elements in LIST, you can 1116 # bring the system to its knees with the memory m4 then requires, or trip 1117 # the m4 --nesting-limit recursion factor. The only way to avoid 1118 # quadratic growth is ensure m4_shift is expanded prior to the recursion. 1119 # Hence the design below. 1120 # 1121 # The M4 manual now includes a chapter devoted to this issue, with 1122 # the lessons learned from m4sugar. And still, this design is only 1123 # optimal for M4 1.6; see foreach.m4 for yet more comments on why 1124 # M4 1.4.x uses yet another implementation. 1125 1126 1127 # m4_foreach(VARIABLE, LIST, EXPRESSION) 1128 # -------------------------------------- 1129 # 1130 # Expand EXPRESSION assigning each value of the LIST to VARIABLE. 1131 # LIST should have the form `item_1, item_2, ..., item_n', i.e. the 1132 # whole list must *quoted*. Quote members too if you don't want them 1133 # to be expanded. 1134 # 1135 # This macro is robust to active symbols: 1136 # | m4_define(active, [ACT, IVE]) 1137 # | m4_foreach(Var, [active, active], [-Var-]) 1138 # => -ACT--IVE--ACT--IVE- 1139 # 1140 # | m4_foreach(Var, [[active], [active]], [-Var-]) 1141 # => -ACT, IVE--ACT, IVE- 1142 # 1143 # | m4_foreach(Var, [[[active]], [[active]]], [-Var-]) 1144 # => -active--active- 1145 # 1146 # This macro is called frequently, so avoid extra expansions such as 1147 # m4_ifval and dnl. Also, since $2 might be quite large, try to use it 1148 # as little as possible in _m4_foreach; each extra use requires that much 1149 # more memory for expansion. So, rather than directly compare $2 against 1150 # [] and use m4_car/m4_cdr for recursion, we instead unbox the list (which 1151 # requires swapping the argument order in the helper), insert an ignored 1152 # third argument, and use m4_shift3 to detect when recursion is complete, 1153 # at which point this looks very much like m4_map_args. 1154 m4_define([m4_foreach], 1155 [m4_if([$2], [], [], 1156 [m4_pushdef([$1])_$0([m4_define([$1],], [)$3], [], 1157 $2)m4_popdef([$1])])]) 1158 1159 # _m4_foreach(PRE, POST, IGNORED, ARG...) 1160 # --------------------------------------- 1161 # Form the common basis of the m4_foreach and m4_map macros. For each 1162 # ARG, expand PRE[ARG]POST[]. The IGNORED argument makes recursion 1163 # easier, and must be supplied rather than implicit. 1164 # 1165 # Please keep foreach.m4 in sync with any adjustments made here. 1166 m4_define([_m4_foreach], 1167 [m4_if([$#], [3], [], 1168 [$1[$4]$2[]$0([$1], [$2], m4_shift3($@))])]) 1169 1170 1171 # m4_foreach_w(VARIABLE, LIST, EXPRESSION) 1172 # ---------------------------------------- 1173 # Like m4_foreach, but the list is whitespace separated. Depending on 1174 # EXPRESSION, it may be more efficient to use m4_map_args_w. 1175 # 1176 # This macro is robust to active symbols: 1177 # m4_foreach_w([Var], [ active 1178 # b act\ 1179 # ive ], [-Var-])end 1180 # => -active--b--active-end 1181 # 1182 # This used to use a slower implementation based on m4_foreach: 1183 # m4_foreach([$1], m4_split(m4_normalize([$2]), [ ]), [$3]) 1184 m4_define([m4_foreach_w], 1185 [m4_pushdef([$1])m4_map_args_w([$2], 1186 [m4_define([$1],], [)$3])m4_popdef([$1])]) 1187 1188 1189 # m4_map(MACRO, LIST) 1190 # m4_mapall(MACRO, LIST) 1191 # ---------------------- 1192 # Invoke MACRO($1), MACRO($2) etc. where $1, $2... are the elements of 1193 # LIST. $1, $2... must in turn be lists, appropriate for m4_apply. 1194 # If LIST contains an empty sublist, m4_map skips the expansion of 1195 # MACRO, while m4_mapall expands MACRO with no arguments. 1196 # 1197 # Since LIST may be quite large, we want to minimize how often it 1198 # appears in the expansion. Rather than use m4_car/m4_cdr iteration, 1199 # we unbox the list, and use _m4_foreach for iteration. For m4_map, 1200 # an empty list behaves like an empty sublist and gets ignored; for 1201 # m4_mapall, we must special-case the empty list. 1202 m4_define([m4_map], 1203 [_m4_foreach([_m4_apply([$1],], [)], [], $2)]) 1204 1205 m4_define([m4_mapall], 1206 [m4_if([$2], [], [], 1207 [_m4_foreach([m4_apply([$1],], [)], [], $2)])]) 1208 1209 1210 # m4_map_sep(MACRO, [SEPARATOR], LIST) 1211 # m4_mapall_sep(MACRO, [SEPARATOR], LIST) 1212 # --------------------------------------- 1213 # Invoke MACRO($1), SEPARATOR, MACRO($2), ..., MACRO($N) where $1, 1214 # $2... $N are the elements of LIST, and are in turn lists appropriate 1215 # for m4_apply. SEPARATOR is expanded, in order to allow the creation 1216 # of a list of arguments by using a single-quoted comma as the 1217 # separator. For each empty sublist, m4_map_sep skips the expansion 1218 # of MACRO and SEPARATOR, while m4_mapall_sep expands MACRO with no 1219 # arguments. 1220 # 1221 # For m4_mapall_sep, merely expand the first iteration without the 1222 # separator, then include separator as part of subsequent recursion; 1223 # but avoid extra expansion of LIST's side-effects via a helper macro. 1224 # For m4_map_sep, things are trickier - we don't know if the first 1225 # list element is an empty sublist, so we must define a self-modifying 1226 # helper macro and use that as the separator instead. 1227 m4_define([m4_map_sep], 1228 [m4_pushdef([m4_Sep], [m4_define([m4_Sep], _m4_defn([m4_unquote]))])]dnl 1229 [_m4_foreach([_m4_apply([m4_Sep([$2])[]$1],], [)], [], $3)m4_popdef([m4_Sep])]) 1230 1231 m4_define([m4_mapall_sep], 1232 [m4_if([$3], [], [], [_$0([$1], [$2], $3)])]) 1233 1234 m4_define([_m4_mapall_sep], 1235 [m4_apply([$1], [$3])_m4_foreach([m4_apply([$2[]$1],], [)], m4_shift2($@))]) 1236 1237 # m4_map_args(EXPRESSION, ARG...) 1238 # ------------------------------- 1239 # Expand EXPRESSION([ARG]) for each argument. More efficient than 1240 # m4_foreach([var], [ARG...], [EXPRESSION(m4_defn([var]))]) 1241 # Shorthand for m4_map_args_sep([EXPRESSION(], [)], [], ARG...). 1242 m4_define([m4_map_args], 1243 [m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], 1244 [$#], [1], [], 1245 [$#], [2], [$1([$2])[]], 1246 [_m4_foreach([$1(], [)], $@)])]) 1247 1248 1249 # m4_map_args_pair(EXPRESSION, [END-EXPR = EXPRESSION], ARG...) 1250 # ------------------------------------------------------------- 1251 # Perform a pairwise grouping of consecutive ARGs, by expanding 1252 # EXPRESSION([ARG1], [ARG2]). If there are an odd number of ARGs, the 1253 # final argument is expanded with END-EXPR([ARGn]). 1254 # 1255 # For example: 1256 # m4_define([show], [($*)m4_newline])dnl 1257 # m4_map_args_pair([show], [], [a], [b], [c], [d], [e])dnl 1258 # => (a,b) 1259 # => (c,d) 1260 # => (e) 1261 # 1262 # Please keep foreach.m4 in sync with any adjustments made here. 1263 m4_define([m4_map_args_pair], 1264 [m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], 1265 [$#], [1], [m4_fatal([$0: too few arguments: $#: $1])], 1266 [$#], [2], [], 1267 [$#], [3], [m4_default([$2], [$1])([$3])[]], 1268 [$#], [4], [$1([$3], [$4])[]], 1269 [$1([$3], [$4])[]$0([$1], [$2], m4_shift(m4_shift3($@)))])]) 1270 1271 1272 # m4_map_args_sep([PRE], [POST], [SEP], ARG...) 1273 # --------------------------------------------- 1274 # Expand PRE[ARG]POST for each argument, with SEP between arguments. 1275 m4_define([m4_map_args_sep], 1276 [m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], 1277 [$#], [1], [], 1278 [$#], [2], [], 1279 [$#], [3], [], 1280 [$#], [4], [$1[$4]$2[]], 1281 [$1[$4]$2[]_m4_foreach([$3[]$1], [$2], m4_shift3($@))])]) 1282 1283 1284 # m4_map_args_w(STRING, [PRE], [POST], [SEP]) 1285 # ------------------------------------------- 1286 # Perform the expansion of PRE[word]POST[] for each word in STRING 1287 # separated by whitespace. More efficient than: 1288 # m4_foreach_w([var], [STRING], [PRE[]m4_defn([var])POST]) 1289 # Additionally, expand SEP between words. 1290 # 1291 # As long as we have to use m4_bpatsubst to split the string, we might 1292 # as well make it also apply PRE and POST; this avoids iteration 1293 # altogether. But we must be careful of any \ in PRE or POST. 1294 # _m4_strip returns a quoted string, but that's okay, since it also 1295 # supplies an empty leading and trailing argument due to our 1296 # intentional whitespace around STRING. We use m4_substr to strip the 1297 # empty elements and remove the extra layer of quoting. 1298 m4_define([m4_map_args_w], 1299 [_$0(_m4_split([ ]m4_flatten([$1])[ ], [[ ]+], 1300 m4_if(m4_index([$2$3$4], [\]), [-1], [[$3[]$4[]$2]], 1301 [m4_bpatsubst([[$3[]$4[]$2]], [\\], [\\\\])])), 1302 m4_len([[]$3[]$4]), m4_len([$4[]$2[]]))]) 1303 1304 m4_define([_m4_map_args_w], 1305 [m4_substr([$1], [$2], m4_eval(m4_len([$1]) - [$2] - [$3]))]) 1306 1307 1308 # m4_stack_foreach(MACRO, FUNC) 1309 # m4_stack_foreach_lifo(MACRO, FUNC) 1310 # ---------------------------------- 1311 # Pass each stacked definition of MACRO to the one-argument macro FUNC. 1312 # m4_stack_foreach proceeds in FIFO order, while m4_stack_foreach_lifo 1313 # processes the topmost definitions first. In addition, FUNC should 1314 # not push or pop definitions of MACRO, and should not expect anything about 1315 # the active definition of MACRO (it will not be the topmost, and may not 1316 # be the one passed to FUNC either). 1317 # 1318 # Some macros simply can't be examined with this method: namely, 1319 # anything involved in the implementation of _m4_stack_reverse. 1320 m4_define([m4_stack_foreach], 1321 [_m4_stack_reverse([$1], [m4_tmp-$1])]dnl 1322 [_m4_stack_reverse([m4_tmp-$1], [$1], [$2(_m4_defn([m4_tmp-$1]))])]) 1323 1324 m4_define([m4_stack_foreach_lifo], 1325 [_m4_stack_reverse([$1], [m4_tmp-$1], [$2(_m4_defn([m4_tmp-$1]))])]dnl 1326 [_m4_stack_reverse([m4_tmp-$1], [$1])]) 1327 1328 # m4_stack_foreach_sep(MACRO, [PRE], [POST], [SEP]) 1329 # m4_stack_foreach_sep_lifo(MACRO, [PRE], [POST], [SEP]) 1330 # ------------------------------------------------------ 1331 # Similar to m4_stack_foreach and m4_stack_foreach_lifo, in that every 1332 # definition of a pushdef stack will be visited. But rather than 1333 # passing the definition as a single argument to a macro, this variant 1334 # expands the concatenation of PRE[]definition[]POST, and expands SEP 1335 # between consecutive expansions. Note that m4_stack_foreach([a], [b]) 1336 # is equivalent to m4_stack_foreach_sep([a], [b(], [)]). 1337 m4_define([m4_stack_foreach_sep], 1338 [_m4_stack_reverse([$1], [m4_tmp-$1])]dnl 1339 [_m4_stack_reverse([m4_tmp-$1], [$1], [$2[]_m4_defn([m4_tmp-$1])$3], [$4[]])]) 1340 1341 m4_define([m4_stack_foreach_sep_lifo], 1342 [_m4_stack_reverse([$1], [m4_tmp-$1], [$2[]_m4_defn([m4_tmp-$1])$3], [$4[]])]dnl 1343 [_m4_stack_reverse([m4_tmp-$1], [$1])]) 1344 1345 1346 # _m4_stack_reverse(OLD, NEW, [ACTION], [SEP]) 1347 # -------------------------------------------- 1348 # A recursive worker for pushdef stack manipulation. Destructively 1349 # copy the OLD stack into the NEW, and expanding ACTION for each 1350 # iteration. After the first iteration, SEP is promoted to the front 1351 # of ACTION (note that SEP should include a trailing [] if it is to 1352 # avoid interfering with ACTION). The current definition is examined 1353 # after the NEW has been pushed but before OLD has been popped; this 1354 # order is important, as ACTION is permitted to operate on either 1355 # _m4_defn([OLD]) or _m4_defn([NEW]). Since the operation is 1356 # destructive, this macro is generally used twice, with a temporary 1357 # macro name holding the swapped copy. 1358 m4_define([_m4_stack_reverse], 1359 [m4_ifdef([$1], [m4_pushdef([$2], 1360 _m4_defn([$1]))$3[]_m4_popdef([$1])$0([$1], [$2], [$4$3])])]) 1361 1362 1363 1364 ## --------------------------- ## 1365 ## 9. More diversion support. ## 1366 ## --------------------------- ## 1367 1368 1369 # m4_cleardivert(DIVERSION-NAME...) 1370 # --------------------------------- 1371 # Discard any text in DIVERSION-NAME. 1372 # 1373 # This works even inside m4_expand. 1374 m4_define([m4_cleardivert], 1375 [m4_if([$#], [0], [m4_fatal([$0: missing argument])], 1376 [_m4_divert_raw([-1])m4_undivert($@)_m4_divert_raw( 1377 _m4_divert(_m4_defn([_m4_divert_diversion]), [-]))])]) 1378 1379 1380 # _m4_divert(DIVERSION-NAME or NUMBER, [NOWARN]) 1381 # ---------------------------------------------- 1382 # If DIVERSION-NAME is the name of a diversion, return its number, 1383 # otherwise if it is a NUMBER return it. Issue a warning about 1384 # the use of a number instead of a name, unless NOWARN is provided. 1385 m4_define([_m4_divert], 1386 [m4_ifdef([_m4_divert($1)], 1387 [m4_indir([_m4_divert($1)])], 1388 [m4_if([$2], [], [m4_warn([syntax], 1389 [prefer named diversions])])$1])]) 1390 1391 # KILL is only used to suppress output. 1392 m4_define([_m4_divert(KILL)], -1) 1393 1394 # The empty diversion name is a synonym for 0. 1395 m4_define([_m4_divert()], 0) 1396 1397 1398 # m4_divert_stack 1399 # --------------- 1400 # Print the diversion stack, if it's nonempty. The caller is 1401 # responsible for any leading or trailing newline. 1402 m4_define([m4_divert_stack], 1403 [m4_stack_foreach_sep_lifo([_m4_divert_stack], [], [], [ 1404 ])]) 1405 1406 1407 # m4_divert_stack_push(MACRO-NAME, DIVERSION-NAME) 1408 # ------------------------------------------------ 1409 # Form an entry of the diversion stack from caller MACRO-NAME and 1410 # entering DIVERSION-NAME and push it. 1411 m4_define([m4_divert_stack_push], 1412 [m4_pushdef([_m4_divert_stack], m4_location[: $1: $2])]) 1413 1414 1415 # m4_divert(DIVERSION-NAME) 1416 # ------------------------- 1417 # Change the diversion stream to DIVERSION-NAME. 1418 m4_define([m4_divert], 1419 [m4_popdef([_m4_divert_stack])]dnl 1420 [m4_define([_m4_divert_diversion], [$1])]dnl 1421 [m4_divert_stack_push([$0], [$1])]dnl 1422 [_m4_divert_raw(_m4_divert([$1]))]) 1423 1424 1425 # m4_divert_push(DIVERSION-NAME, [NOWARN]) 1426 # ---------------------------------------- 1427 # Change the diversion stream to DIVERSION-NAME, while stacking old values. 1428 # For internal use only: if NOWARN is not empty, DIVERSION-NAME can be a 1429 # number instead of a name. 1430 m4_define([m4_divert_push], 1431 [m4_divert_stack_push([$0], [$1])]dnl 1432 [m4_pushdef([_m4_divert_diversion], [$1])]dnl 1433 [_m4_divert_raw(_m4_divert([$1], [$2]))]) 1434 1435 1436 # m4_divert_pop([DIVERSION-NAME]) 1437 # ------------------------------- 1438 # Change the diversion stream to its previous value, unstacking it. 1439 # If specified, verify we left DIVERSION-NAME. 1440 # When we pop the last value from the stack, we divert to -1. 1441 m4_define([m4_divert_pop], 1442 [m4_if([$1], [], [], 1443 [$1], _m4_defn([_m4_divert_diversion]), [], 1444 [m4_fatal([$0($1): diversion mismatch: 1445 ]m4_divert_stack)])]dnl 1446 [_m4_popdef([_m4_divert_stack], [_m4_divert_diversion])]dnl 1447 [m4_ifdef([_m4_divert_diversion], [], 1448 [m4_fatal([too many m4_divert_pop])])]dnl 1449 [_m4_divert_raw(_m4_divert(_m4_defn([_m4_divert_diversion]), [-]))]) 1450 1451 1452 # m4_divert_text(DIVERSION-NAME, CONTENT) 1453 # --------------------------------------- 1454 # Output CONTENT into DIVERSION-NAME (which may be a number actually). 1455 # An end of line is appended for free to CONTENT. 1456 m4_define([m4_divert_text], 1457 [m4_divert_push([$1])$2 1458 m4_divert_pop([$1])]) 1459 1460 1461 # m4_divert_once(DIVERSION-NAME, CONTENT) 1462 # --------------------------------------- 1463 # Output CONTENT into DIVERSION-NAME once, if not already there. 1464 # An end of line is appended for free to CONTENT. 1465 m4_define([m4_divert_once], 1466 [m4_expand_once([m4_divert_text([$1], [$2])])]) 1467 1468 1469 # _m4_divert_unsafe(DIVERSION-NAME) 1470 # --------------------------------- 1471 # Issue a warning that the attempt to change the current diversion to 1472 # DIVERSION-NAME is unsafe, because this macro is being expanded 1473 # during argument collection of m4_expand. 1474 m4_define([_m4_divert_unsafe], 1475 [m4_fatal([$0: cannot change diversion to `$1' inside m4_expand])]) 1476 1477 1478 # m4_undivert(DIVERSION-NAME...) 1479 # ------------------------------ 1480 # Undivert DIVERSION-NAME. Unlike the M4 version, this requires at 1481 # least one DIVERSION-NAME; also, due to support for named diversions, 1482 # this should not be used to undivert files. 1483 m4_define([m4_undivert], 1484 [m4_if([$#], [0], [m4_fatal([$0: missing argument])], 1485 [$#], [1], [_m4_undivert(_m4_divert([$1]))], 1486 [m4_map_args([$0], $@)])]) 1487 1488 1489 ## --------------------------------------------- ## 1490 ## 10. Defining macros with bells and whistles. ## 1491 ## --------------------------------------------- ## 1492 1493 # `m4_defun' is basically `m4_define' but it equips the macro with the 1494 # needed machinery for `m4_require'. A macro must be m4_defun'd if 1495 # either it is m4_require'd, or it m4_require's. 1496 # 1497 # Two things deserve attention and are detailed below: 1498 # 1. Implementation of m4_require 1499 # 2. Keeping track of the expansion stack 1500 # 1501 # 1. Implementation of m4_require 1502 # =============================== 1503 # 1504 # Of course m4_defun calls m4_provide, so that a macro which has 1505 # been expanded is not expanded again when m4_require'd, but the 1506 # difficult part is the proper expansion of macros when they are 1507 # m4_require'd. 1508 # 1509 # The implementation is based on three ideas, (i) using diversions to 1510 # prepare the expansion of the macro and its dependencies (by Franc,ois 1511 # Pinard), (ii) expand the most recently m4_require'd macros _after_ 1512 # the previous macros (by Axel Thimm), and (iii) track instances of 1513 # provide before require (by Eric Blake). 1514 # 1515 # 1516 # The first idea: why use diversions? 1517 # ----------------------------------- 1518 # 1519 # When a macro requires another, the other macro is expanded in new 1520 # diversion, GROW. When the outer macro is fully expanded, we first 1521 # undivert the most nested diversions (GROW - 1...), and finally 1522 # undivert GROW. To understand why we need several diversions, 1523 # consider the following example: 1524 # 1525 # | m4_defun([TEST1], [Test...m4_require([TEST2])1]) 1526 # | m4_defun([TEST2], [Test...m4_require([TEST3])2]) 1527 # | m4_defun([TEST3], [Test...3]) 1528 # 1529 # Because m4_require is not required to be first in the outer macros, we 1530 # must keep the expansions of the various levels of m4_require separated. 1531 # Right before executing the epilogue of TEST1, we have: 1532 # 1533 # GROW - 2: Test...3 1534 # GROW - 1: Test...2 1535 # GROW: Test...1 1536 # BODY: 1537 # 1538 # Finally the epilogue of TEST1 undiverts GROW - 2, GROW - 1, and 1539 # GROW into the regular flow, BODY. 1540 # 1541 # GROW - 2: 1542 # GROW - 1: 1543 # GROW: 1544 # BODY: Test...3; Test...2; Test...1 1545 # 1546 # (The semicolons are here for clarification, but of course are not 1547 # emitted.) This is what Autoconf 2.0 (I think) to 2.13 (I'm sure) 1548 # implement. 1549 # 1550 # 1551 # The second idea: first required first out 1552 # ----------------------------------------- 1553 # 1554 # The natural implementation of the idea above is buggy and produces 1555 # very surprising results in some situations. Let's consider the 1556 # following example to explain the bug: 1557 # 1558 # | m4_defun([TEST1], [m4_require([TEST2a])m4_require([TEST2b])]) 1559 # | m4_defun([TEST2a], []) 1560 # | m4_defun([TEST2b], [m4_require([TEST3])]) 1561 # | m4_defun([TEST3], [m4_require([TEST2a])]) 1562 # | 1563 # | AC_INIT 1564 # | TEST1 1565 # 1566 # The dependencies between the macros are: 1567 # 1568 # 3 --- 2b 1569 # / \ is m4_require'd by 1570 # / \ left -------------------- right 1571 # 2a ------------ 1 1572 # 1573 # If you strictly apply the rules given in the previous section you get: 1574 # 1575 # GROW - 2: TEST3 1576 # GROW - 1: TEST2a; TEST2b 1577 # GROW: TEST1 1578 # BODY: 1579 # 1580 # (TEST2a, although required by TEST3 is not expanded in GROW - 3 1581 # because is has already been expanded before in GROW - 1, so it has 1582 # been AC_PROVIDE'd, so it is not expanded again) so when you undivert 1583 # the stack of diversions, you get: 1584 # 1585 # GROW - 2: 1586 # GROW - 1: 1587 # GROW: 1588 # BODY: TEST3; TEST2a; TEST2b; TEST1 1589 # 1590 # i.e., TEST2a is expanded after TEST3 although the latter required the 1591 # former. 1592 # 1593 # Starting from 2.50, we use an implementation provided by Axel Thimm. 1594 # The idea is simple: the order in which macros are emitted must be the 1595 # same as the one in which macros are expanded. (The bug above can 1596 # indeed be described as: a macro has been m4_provide'd before its 1597 # dependent, but it is emitted after: the lack of correlation between 1598 # emission and expansion order is guilty). 1599 # 1600 # How to do that? You keep the stack of diversions to elaborate the 1601 # macros, but each time a macro is fully expanded, emit it immediately. 1602 # 1603 # In the example above, when TEST2a is expanded, but it's epilogue is 1604 # not run yet, you have: 1605 # 1606 # GROW - 2: 1607 # GROW - 1: TEST2a 1608 # GROW: Elaboration of TEST1 1609 # BODY: 1610 # 1611 # The epilogue of TEST2a emits it immediately: 1612 # 1613 # GROW - 2: 1614 # GROW - 1: 1615 # GROW: Elaboration of TEST1 1616 # BODY: TEST2a 1617 # 1618 # TEST2b then requires TEST3, so right before the epilogue of TEST3, you 1619 # have: 1620 # 1621 # GROW - 2: TEST3 1622 # GROW - 1: Elaboration of TEST2b 1623 # GROW: Elaboration of TEST1 1624 # BODY: TEST2a 1625 # 1626 # The epilogue of TEST3 emits it: 1627 # 1628 # GROW - 2: 1629 # GROW - 1: Elaboration of TEST2b 1630 # GROW: Elaboration of TEST1 1631 # BODY: TEST2a; TEST3 1632 # 1633 # TEST2b is now completely expanded, and emitted: 1634 # 1635 # GROW - 2: 1636 # GROW - 1: 1637 # GROW: Elaboration of TEST1 1638 # BODY: TEST2a; TEST3; TEST2b 1639 # 1640 # and finally, TEST1 is finished and emitted: 1641 # 1642 # GROW - 2: 1643 # GROW - 1: 1644 # GROW: 1645 # BODY: TEST2a; TEST3; TEST2b: TEST1 1646 # 1647 # The idea is simple, but the implementation is a bit involved. If 1648 # you are like me, you will want to see the actual functioning of this 1649 # implementation to be convinced. The next section gives the full 1650 # details. 1651 # 1652 # 1653 # The Axel Thimm implementation at work 1654 # ------------------------------------- 1655 # 1656 # We consider the macros above, and this configure.ac: 1657 # 1658 # AC_INIT 1659 # TEST1 1660 # 1661 # You should keep the definitions of _m4_defun_pro, _m4_defun_epi, and 1662 # m4_require at hand to follow the steps. 1663 # 1664 # This implementation tries not to assume that the current diversion is 1665 # BODY, so as soon as a macro (m4_defun'd) is expanded, we first 1666 # record the current diversion under the name _m4_divert_dump (denoted 1667 # DUMP below for short). This introduces an important difference with 1668 # the previous versions of Autoconf: you cannot use m4_require if you 1669 # are not inside an m4_defun'd macro, and especially, you cannot 1670 # m4_require directly from the top level. 1671 # 1672 # We have not tried to simulate the old behavior (better yet, we 1673 # diagnose it), because it is too dangerous: a macro m4_require'd from 1674 # the top level is expanded before the body of `configure', i.e., before 1675 # any other test was run. I let you imagine the result of requiring 1676 # AC_STDC_HEADERS for instance, before AC_PROG_CC was actually run.... 1677 # 1678 # After AC_INIT was run, the current diversion is BODY. 1679 # * AC_INIT was run 1680 # DUMP: undefined 1681 # diversion stack: BODY |- 1682 # 1683 # * TEST1 is expanded 1684 # The prologue of TEST1 sets _m4_divert_dump, which is the diversion 1685 # where the current elaboration will be dumped, to the current 1686 # diversion. It also m4_divert_push to GROW, where the full 1687 # expansion of TEST1 and its dependencies will be elaborated. 1688 # DUMP: BODY 1689 # BODY: empty 1690 # diversions: GROW, BODY |- 1691 # 1692 # * TEST1 requires TEST2a 1693 # _m4_require_call m4_divert_pushes another temporary diversion, 1694 # GROW - 1, and expands TEST2a in there. 1695 # DUMP: BODY 1696 # BODY: empty 1697 # GROW - 1: TEST2a 1698 # diversions: GROW - 1, GROW, BODY |- 1699 # Then the content of the temporary diversion is moved to DUMP and the 1700 # temporary diversion is popped. 1701 # DUMP: BODY 1702 # BODY: TEST2a 1703 # diversions: GROW, BODY |- 1704 # 1705 # * TEST1 requires TEST2b 1706 # Again, _m4_require_call pushes GROW - 1 and heads to expand TEST2b. 1707 # DUMP: BODY 1708 # BODY: TEST2a 1709 # diversions: GROW - 1, GROW, BODY |- 1710 # 1711 # * TEST2b requires TEST3 1712 # _m4_require_call pushes GROW - 2 and expands TEST3 here. 1713 # (TEST3 requires TEST2a, but TEST2a has already been m4_provide'd, so 1714 # nothing happens.) 1715 # DUMP: BODY 1716 # BODY: TEST2a 1717 # GROW - 2: TEST3 1718 # diversions: GROW - 2, GROW - 1, GROW, BODY |- 1719 # Then the diversion is appended to DUMP, and popped. 1720 # DUMP: BODY 1721 # BODY: TEST2a; TEST3 1722 # diversions: GROW - 1, GROW, BODY |- 1723 # 1724 # * TEST1 requires TEST2b (contd.) 1725 # The content of TEST2b is expanded... 1726 # DUMP: BODY 1727 # BODY: TEST2a; TEST3 1728 # GROW - 1: TEST2b, 1729 # diversions: GROW - 1, GROW, BODY |- 1730 # ... and moved to DUMP. 1731 # DUMP: BODY 1732 # BODY: TEST2a; TEST3; TEST2b 1733 # diversions: GROW, BODY |- 1734 # 1735 # * TEST1 is expanded: epilogue 1736 # TEST1's own content is in GROW... 1737 # DUMP: BODY 1738 # BODY: TEST2a; TEST3; TEST2b 1739 # GROW: TEST1 1740 # diversions: BODY |- 1741 # ... and it's epilogue moves it to DUMP and then undefines DUMP. 1742 # DUMP: undefined 1743 # BODY: TEST2a; TEST3; TEST2b; TEST1 1744 # diversions: BODY |- 1745 # 1746 # 1747 # The third idea: track macros provided before they were required 1748 # --------------------------------------------------------------- 1749 # 1750 # Using just the first two ideas, Autoconf 2.50 through 2.63 still had 1751 # a subtle bug for more than seven years. Let's consider the 1752 # following example to explain the bug: 1753 # 1754 # | m4_defun([TEST1], [1]) 1755 # | m4_defun([TEST2], [2[]m4_require([TEST1])]) 1756 # | m4_defun([TEST3], [3 TEST1 m4_require([TEST2])]) 1757 # | TEST3 1758 # 1759 # After the prologue of TEST3, we are collecting text in GROW with the 1760 # intent of dumping it in BODY during the epilogue. Next, we 1761 # encounter the direct invocation of TEST1, which provides the macro 1762 # in place in GROW. From there, we encounter a requirement for TEST2, 1763 # which must be collected in a new diversion. While expanding TEST2, 1764 # we encounter a requirement for TEST1, but since it has already been 1765 # expanded, the Axel Thimm algorithm states that we can treat it as a 1766 # no-op. But that would lead to an end result of `2 3 1', meaning 1767 # that we have once again output a macro (TEST2) prior to its 1768 # requirements (TEST1). 1769 # 1770 # The problem can only occur if a single defun'd macro first provides, 1771 # then later indirectly requires, the same macro. Note that directly 1772 # expanding then requiring a macro is okay: because the dependency was 1773 # met, the require phase can be a no-op. For that matter, the outer 1774 # macro can even require two helpers, where the first helper expands 1775 # the macro, and the second helper indirectly requires the macro. 1776 # Out-of-order expansion is only present if the inner macro is 1777 # required by something that will be hoisted in front of where the 1778 # direct expansion occurred. In other words, we must be careful not 1779 # to warn on: 1780 # 1781 # | m4_defun([TEST4], [4]) 1782 # | m4_defun([TEST5], [5 TEST4 m4_require([TEST4])]) 1783 # | TEST5 => 5 4 1784 # 1785 # or even the more complex: 1786 # 1787 # | m4_defun([TEST6], [6]) 1788 # | m4_defun([TEST7], [7 TEST6]) 1789 # | m4_defun([TEST8], [8 m4_require([TEST6])]) 1790 # | m4_defun([TEST9], [9 m4_require([TEST8])]) 1791 # | m4_defun([TEST10], [10 m4_require([TEST7]) m4_require([TEST9])]) 1792 # | TEST10 => 7 6 8 9 10 1793 # 1794 # So, to detect whether a require was direct or indirect, m4_defun and 1795 # m4_require track the name of the macro that caused a diversion to be 1796 # created (using the stack _m4_diverting, coupled with an O(1) lookup 1797 # _m4_diverting([NAME])), and m4_provide stores the name associated 1798 # with the diversion at which a macro was provided. A require call is 1799 # direct if it occurs within the same diversion where the macro was 1800 # provided, or if the diversion associated with the providing context 1801 # has been collected. 1802 # 1803 # The implementation of the warning involves tracking the set of 1804 # macros which have been provided since the start of the outermost 1805 # defun'd macro (the set is named _m4_provide). When starting an 1806 # outermost macro, the set is emptied; when a macro is provided, it is 1807 # added to the set; when require expands the body of a macro, it is 1808 # removed from the set; and when a macro is indirectly required, the 1809 # set is checked. If a macro is in the set, then it has been provided 1810 # before it was required, and we satisfy dependencies by expanding the 1811 # macro as if it had never been provided; in the example given above, 1812 # this means we now output `1 2 3 1'. Meanwhile, a warning is issued 1813 # to inform the user that her macros trigger the bug in older autoconf 1814 # versions, and that her output file now contains redundant contents 1815 # (and possibly new problems, if the repeated macro was not 1816 # idempotent). Meanwhile, macros defined by m4_defun_once instead of 1817 # m4_defun are idempotent, avoiding any warning or duplicate output. 1818 # 1819 # 1820 # 2. Keeping track of the expansion stack 1821 # ======================================= 1822 # 1823 # When M4 expansion goes wrong it is often extremely hard to find the 1824 # path amongst macros that drove to the failure. What is needed is 1825 # the stack of macro `calls'. One could imagine that GNU M4 would 1826 # maintain a stack of macro expansions, unfortunately it doesn't, so 1827 # we do it by hand. This is of course extremely costly, but the help 1828 # this stack provides is worth it. Nevertheless to limit the 1829 # performance penalty this is implemented only for m4_defun'd macros, 1830 # not for define'd macros. 1831 # 1832 # Each time we enter an m4_defun'd macros, we add a definition in 1833 # _m4_expansion_stack, and when we exit the macro, we remove it (thanks 1834 # to pushdef/popdef). m4_stack_foreach is used to print the expansion 1835 # stack in the rare cases when it's needed. 1836 # 1837 # In addition, we want to detect circular m4_require dependencies. 1838 # Each time we expand a macro FOO we define _m4_expanding(FOO); and 1839 # m4_require(BAR) simply checks whether _m4_expanding(BAR) is defined. 1840 1841 1842 # m4_expansion_stack 1843 # ------------------ 1844 # Expands to the entire contents of the expansion stack. The caller 1845 # must supply a trailing newline. This macro always prints a 1846 # location; check whether _m4_expansion_stack is defined to filter out 1847 # the case when no defun'd macro is in force. 1848 m4_define([m4_expansion_stack], 1849 [m4_stack_foreach_sep_lifo([_$0], [_$0_entry(], [) 1850 ])m4_location[: the top level]]) 1851 1852 # _m4_expansion_stack_entry(MACRO) 1853 # -------------------------------- 1854 # Format an entry for MACRO found on the expansion stack. 1855 m4_define([_m4_expansion_stack_entry], 1856 [_m4_defn([m4_location($1)])[: $1 is expanded from...]]) 1857 1858 # m4_expansion_stack_push(MACRO) 1859 # ------------------------------ 1860 # Form an entry of the expansion stack on entry to MACRO and push it. 1861 m4_define([m4_expansion_stack_push], 1862 [m4_pushdef([_m4_expansion_stack], [$1])]) 1863 1864 1865 # _m4_divert(GROW) 1866 # ---------------- 1867 # This diversion is used by the m4_defun/m4_require machinery. It is 1868 # important to keep room before GROW because for each nested 1869 # AC_REQUIRE we use an additional diversion (i.e., two m4_require's 1870 # will use GROW - 2. More than 3 levels has never seemed to be 1871 # needed.) 1872 # 1873 # ... 1874 # - GROW - 2 1875 # m4_require'd code, 2 level deep 1876 # - GROW - 1 1877 # m4_require'd code, 1 level deep 1878 # - GROW 1879 # m4_defun'd macros are elaborated here. 1880 1881 m4_define([_m4_divert(GROW)], 10000) 1882 1883 1884 # _m4_defun_pro(MACRO-NAME) 1885 # ------------------------- 1886 # The prologue for Autoconf macros. 1887 # 1888 # This is called frequently, so minimize the number of macro invocations 1889 # by avoiding dnl and m4_defn overhead. 1890 m4_define([_m4_defun_pro], 1891 [m4_ifdef([_m4_expansion_stack], [], [_m4_defun_pro_outer([$1])])]dnl 1892 [m4_expansion_stack_push([$1])m4_pushdef([_m4_expanding($1)])]) 1893 1894 m4_define([_m4_defun_pro_outer], 1895 [m4_set_delete([_m4_provide])]dnl 1896 [m4_pushdef([_m4_diverting([$1])])m4_pushdef([_m4_diverting], [$1])]dnl 1897 [m4_pushdef([_m4_divert_dump], m4_divnum)m4_divert_push([GROW])]) 1898 1899 # _m4_defun_epi(MACRO-NAME) 1900 # ------------------------- 1901 # The Epilogue for Autoconf macros. MACRO-NAME only helps tracing 1902 # the PRO/EPI pairs. 1903 # 1904 # This is called frequently, so minimize the number of macro invocations 1905 # by avoiding dnl and m4_popdef overhead. 1906 m4_define([_m4_defun_epi], 1907 [_m4_popdef([_m4_expanding($1)], [_m4_expansion_stack])]dnl 1908 [m4_ifdef([_m4_expansion_stack], [], [_m4_defun_epi_outer([$1])])]dnl 1909 [m4_provide([$1])]) 1910 1911 m4_define([_m4_defun_epi_outer], 1912 [_m4_popdef([_m4_divert_dump], [_m4_diverting([$1])], [_m4_diverting])]dnl 1913 [m4_divert_pop([GROW])m4_undivert([GROW])]) 1914 1915 1916 # _m4_divert_dump 1917 # --------------- 1918 # If blank, we are outside of any defun'd macro. Otherwise, expands 1919 # to the diversion number (not name) where require'd macros should be 1920 # moved once completed. 1921 m4_define([_m4_divert_dump]) 1922 1923 1924 # m4_divert_require(DIVERSION, NAME-TO-CHECK, [BODY-TO-EXPAND]) 1925 # ------------------------------------------------------------- 1926 # Same as m4_require, but BODY-TO-EXPAND goes into the named DIVERSION; 1927 # requirements still go in the current diversion though. 1928 # 1929 m4_define([m4_divert_require], 1930 [m4_ifdef([_m4_expanding($2)], 1931 [m4_fatal([$0: circular dependency of $2])])]dnl 1932 [m4_if(_m4_divert_dump, [], 1933 [m4_fatal([$0($2): cannot be used outside of an m4_defun'd macro])])]dnl 1934 [m4_provide_if([$2], [], 1935 [_m4_require_call([$2], [$3], _m4_divert([$1], [-]))])]) 1936 1937 1938 # m4_defun(NAME, EXPANSION, [MACRO = m4_define]) 1939 # ---------------------------------------------- 1940 # Define a macro NAME which automatically provides itself. Add 1941 # machinery so the macro automatically switches expansion to the 1942 # diversion stack if it is not already using it, prior to EXPANSION. 1943 # In this case, once finished, it will bring back all the code 1944 # accumulated in the diversion stack. This, combined with m4_require, 1945 # achieves the topological ordering of macros. We don't use this 1946 # macro to define some frequently called macros that are not involved 1947 # in ordering constraints, to save m4 processing. 1948 # 1949 # MACRO is an undocumented argument; when set to m4_pushdef, and NAME 1950 # is already defined, the new definition is added to the pushdef 1951 # stack, rather than overwriting the current definition. It can thus 1952 # be used to write self-modifying macros, which pop themselves to a 1953 # previously m4_define'd definition so that subsequent use of the 1954 # macro is faster. 1955 m4_define([m4_defun], 1956 [m4_define([m4_location($1)], m4_location)]dnl 1957 [m4_default([$3], [m4_define])([$1], 1958 [_m4_defun_pro(]m4_dquote($[0])[)$2[]_m4_defun_epi(]m4_dquote($[0])[)])]) 1959 1960 1961 # m4_defun_init(NAME, INIT, COMMON) 1962 # --------------------------------- 1963 # Like m4_defun, but split EXPANSION into two portions: INIT which is 1964 # done only the first time NAME is invoked, and COMMON which is 1965 # expanded every time. 1966 # 1967 # For now, the COMMON definition is always m4_define'd, giving an even 1968 # lighter-weight definition. m4_defun allows self-providing, but once 1969 # a macro is provided, m4_require no longer cares if it is m4_define'd 1970 # or m4_defun'd. m4_defun also provides location tracking to identify 1971 # dependency bugs, but once the INIT has been expanded, we know there 1972 # are no dependency bugs. However, if a future use needs COMMON to be 1973 # m4_defun'd, we can add a parameter, similar to the third parameter 1974 # to m4_defun. 1975 m4_define([m4_defun_init], 1976 [m4_define([$1], [$3[]])m4_defun([$1], 1977 [$2[]_m4_popdef(]m4_dquote($[0])[)m4_indir(]m4_dquote($[0])dnl 1978 [m4_if(]m4_dquote($[#])[, [0], [], ]m4_dquote([,$]@)[))], [m4_pushdef])]) 1979 1980 1981 # m4_defun_once(NAME, EXPANSION) 1982 # ------------------------------ 1983 # Like m4_defun, but guarantee that EXPANSION only happens once 1984 # (thereafter, using NAME is a no-op). 1985 # 1986 # If _m4_divert_dump is empty, we are called at the top level; 1987 # otherwise, we must ensure that we are required in front of the 1988 # current defun'd macro. Use a helper macro so that EXPANSION need 1989 # only occur once in the definition of NAME, since it might be large. 1990 m4_define([m4_defun_once], 1991 [m4_define([m4_location($1)], m4_location)]dnl 1992 [m4_define([$1], [_m4_defun_once([$1], [$2], m4_if(_m4_divert_dump, [], 1993 [[_m4_defun_pro([$1])m4_unquote(], [)_m4_defun_epi([$1])]], 1994 m4_ifdef([_m4_diverting([$1])], [-]), [-], [[m4_unquote(], [)]], 1995 [[_m4_require_call([$1],], [, _m4_divert_dump)]]))])]) 1996 1997 m4_define([_m4_defun_once], 1998 [m4_pushdef([$1])$3[$2[]m4_provide([$1])]$4]) 1999 2000 2001 # m4_pattern_forbid(ERE, [WHY]) 2002 # ----------------------------- 2003 # Declare that no token matching the forbidden extended regular 2004 # expression ERE should be seen in the output unless... 2005 m4_define([m4_pattern_forbid], []) 2006 2007 2008 # m4_pattern_allow(ERE) 2009 # --------------------- 2010 # ... that token also matches the allowed extended regular expression ERE. 2011 # Both used via traces. 2012 m4_define([m4_pattern_allow], []) 2013 2014 2015 ## --------------------------------- ## 2016 ## 11. Dependencies between macros. ## 2017 ## --------------------------------- ## 2018 2019 2020 # m4_before(THIS-MACRO-NAME, CALLED-MACRO-NAME) 2021 # --------------------------------------------- 2022 # Issue a warning if CALLED-MACRO-NAME was called before THIS-MACRO-NAME. 2023 m4_define([m4_before], 2024 [m4_provide_if([$2], 2025 [m4_warn([syntax], [$2 was called before $1])])]) 2026 2027 2028 # m4_require(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK]) 2029 # ----------------------------------------------------------- 2030 # If NAME-TO-CHECK has never been expanded (actually, if it is not 2031 # m4_provide'd), expand BODY-TO-EXPAND *before* the current macro 2032 # expansion; follow the expansion with a newline. Once expanded, emit 2033 # it in _m4_divert_dump. Keep track of the m4_require chain in 2034 # _m4_expansion_stack. 2035 # 2036 # The normal cases are: 2037 # 2038 # - NAME-TO-CHECK == BODY-TO-EXPAND 2039 # Which you can use for regular macros with or without arguments, e.g., 2040 # m4_require([AC_PROG_CC], [AC_PROG_CC]) 2041 # m4_require([AC_CHECK_HEADERS(threads.h)], [AC_CHECK_HEADERS(threads.h)]) 2042 # which is just the same as 2043 # m4_require([AC_PROG_CC]) 2044 # m4_require([AC_CHECK_HEADERS(threads.h)]) 2045 # 2046 # - BODY-TO-EXPAND == m4_indir([NAME-TO-CHECK]) 2047 # In the case of macros with irregular names. For instance: 2048 # m4_require([AC_LANG_COMPILER(C)], [indir([AC_LANG_COMPILER(C)])]) 2049 # which means `if the macro named `AC_LANG_COMPILER(C)' (the parens are 2050 # part of the name, it is not an argument) has not been run, then 2051 # call it.' 2052 # Had you used 2053 # m4_require([AC_LANG_COMPILER(C)], [AC_LANG_COMPILER(C)]) 2054 # then m4_require would have tried to expand `AC_LANG_COMPILER(C)', i.e., 2055 # call the macro `AC_LANG_COMPILER' with `C' as argument. 2056 # 2057 # You could argue that `AC_LANG_COMPILER', when it receives an argument 2058 # such as `C' should dispatch the call to `AC_LANG_COMPILER(C)'. But this 2059 # `extension' prevents `AC_LANG_COMPILER' from having actual arguments that 2060 # it passes to `AC_LANG_COMPILER(C)'. 2061 # 2062 # This is called frequently, so minimize the number of macro invocations 2063 # by avoiding dnl and other overhead on the common path. 2064 m4_define([m4_require], 2065 [m4_ifdef([_m4_expanding($1)], 2066 [m4_fatal([$0: circular dependency of $1])])]dnl 2067 [m4_if(_m4_divert_dump, [], 2068 [m4_fatal([$0($1): cannot be used outside of an ]dnl 2069 m4_if([$0], [m4_require], [[m4_defun]], [[AC_DEFUN]])['d macro])])]dnl 2070 [m4_provide_if([$1], [m4_set_contains([_m4_provide], [$1], 2071 [_m4_require_check([$1], _m4_defn([m4_provide($1)]), [$0])], [m4_ignore])], 2072 [_m4_require_call])([$1], [$2], _m4_divert_dump)]) 2073 2074 2075 # _m4_require_call(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK], 2076 # DIVERSION-NUMBER) 2077 # ----------------------------------------------------------------- 2078 # If m4_require decides to expand the body, it calls this macro. The 2079 # expansion is placed in DIVERSION-NUMBER. 2080 # 2081 # This is called frequently, so minimize the number of macro invocations 2082 # by avoiding dnl and other overhead on the common path. 2083 m4_define([_m4_require_call], 2084 [m4_pushdef([_m4_divert_grow], m4_decr(_m4_divert_grow))]dnl 2085 [m4_pushdef([_m4_diverting([$1])])m4_pushdef([_m4_diverting], [$1])]dnl 2086 [m4_divert_push(_m4_divert_grow, [-])]dnl 2087 [m4_if([$2], [], [$1], [$2]) 2088 m4_provide_if([$1], [m4_set_remove([_m4_provide], [$1])], 2089 [m4_warn([syntax], [$1 is m4_require'd but not m4_defun'd])])]dnl 2090 [_m4_divert_raw($3)_m4_undivert(_m4_divert_grow)]dnl 2091 [m4_divert_pop(_m4_divert_grow)_m4_popdef([_m4_divert_grow], 2092 [_m4_diverting([$1])], [_m4_diverting])]) 2093 2094 2095 # _m4_require_check(NAME-TO-CHECK, OWNER, CALLER) 2096 # ----------------------------------------------- 2097 # NAME-TO-CHECK has been identified as previously expanded in the 2098 # diversion owned by OWNER. If this is a problem, warn on behalf of 2099 # CALLER and return _m4_require_call; otherwise return m4_ignore. 2100 m4_define([_m4_require_check], 2101 [m4_if(_m4_defn([_m4_diverting]), [$2], [m4_ignore], 2102 m4_ifdef([_m4_diverting([$2])], [-]), [-], [m4_warn([syntax], 2103 [$3: `$1' was expanded before it was required 2104 http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required])_m4_require_call], 2105 [m4_ignore])]) 2106 2107 2108 # _m4_divert_grow 2109 # --------------- 2110 # The counter for _m4_require_call. 2111 m4_define([_m4_divert_grow], _m4_divert([GROW])) 2112 2113 2114 # m4_expand_once(TEXT, [WITNESS = TEXT]) 2115 # -------------------------------------- 2116 # If TEXT has never been expanded, expand it *here*. Use WITNESS as 2117 # as a memory that TEXT has already been expanded. 2118 m4_define([m4_expand_once], 2119 [m4_provide_if(m4_default_quoted([$2], [$1]), 2120 [], 2121 [m4_provide(m4_default_quoted([$2], [$1]))[]$1])]) 2122 2123 2124 # m4_provide(MACRO-NAME) 2125 # ---------------------- 2126 m4_define([m4_provide], 2127 [m4_ifdef([m4_provide($1)], [], 2128 [m4_set_add([_m4_provide], [$1], [m4_define([m4_provide($1)], 2129 m4_ifdef([_m4_diverting], [_m4_defn([_m4_diverting])]))])])]) 2130 2131 2132 # m4_provide_if(MACRO-NAME, IF-PROVIDED, IF-NOT-PROVIDED) 2133 # ------------------------------------------------------- 2134 # If MACRO-NAME is provided do IF-PROVIDED, else IF-NOT-PROVIDED. 2135 # The purpose of this macro is to provide the user with a means to 2136 # check macros which are provided without letting her know how the 2137 # information is coded. 2138 m4_define([m4_provide_if], 2139 [m4_ifdef([m4_provide($1)], 2140 [$2], [$3])]) 2141 2142 2143 ## --------------------- ## 2144 ## 12. Text processing. ## 2145 ## --------------------- ## 2146 2147 2148 # m4_cr_letters 2149 # m4_cr_LETTERS 2150 # m4_cr_Letters 2151 # ------------- 2152 m4_define([m4_cr_letters], [abcdefghijklmnopqrstuvwxyz]) 2153 m4_define([m4_cr_LETTERS], [ABCDEFGHIJKLMNOPQRSTUVWXYZ]) 2154 m4_define([m4_cr_Letters], 2155 m4_defn([m4_cr_letters])dnl 2156 m4_defn([m4_cr_LETTERS])dnl 2157 ) 2158 2159 2160 # m4_cr_digits 2161 # ------------ 2162 m4_define([m4_cr_digits], [0123456789]) 2163 2164 2165 # m4_cr_alnum 2166 # ----------- 2167 m4_define([m4_cr_alnum], 2168 m4_defn([m4_cr_Letters])dnl 2169 m4_defn([m4_cr_digits])dnl 2170 ) 2171 2172 2173 # m4_cr_symbols1 2174 # m4_cr_symbols2 2175 # -------------- 2176 m4_define([m4_cr_symbols1], 2177 m4_defn([m4_cr_Letters])dnl 2178 _) 2179 2180 m4_define([m4_cr_symbols2], 2181 m4_defn([m4_cr_symbols1])dnl 2182 m4_defn([m4_cr_digits])dnl 2183 ) 2184 2185 # m4_cr_all 2186 # --------- 2187 # The character range representing everything, with `-' as the last 2188 # character, since it is special to m4_translit. Use with care, because 2189 # it contains characters special to M4 (fortunately, both ASCII and EBCDIC 2190 # have [] in order, so m4_defn([m4_cr_all]) remains a valid string). It 2191 # also contains characters special to terminals, so it should never be 2192 # displayed in an error message. Also, attempts to map [ and ] to other 2193 # characters via m4_translit must deal with the fact that m4_translit does 2194 # not add quotes to the output. 2195 # 2196 # In EBCDIC, $ is immediately followed by *, which leads to problems 2197 # if m4_cr_all is inlined into a macro definition; so swap them. 2198 # 2199 # It is mainly useful in generating inverted character range maps, for use 2200 # in places where m4_translit is faster than an equivalent m4_bpatsubst; 2201 # the regex `[^a-z]' is equivalent to: 2202 # m4_translit(m4_dquote(m4_defn([m4_cr_all])), [a-z]) 2203 m4_define([m4_cr_all], 2204 m4_translit(m4_dquote(m4_format(m4_dquote(m4_for( 2205 ,1,255,,[[%c]]))m4_for([i],1,255,,[,i]))), [$*-], [*$])-) 2206 2207 2208 # _m4_define_cr_not(CATEGORY) 2209 # --------------------------- 2210 # Define m4_cr_not_CATEGORY as the inverse of m4_cr_CATEGORY. 2211 m4_define([_m4_define_cr_not], 2212 [m4_define([m4_cr_not_$1], 2213 m4_translit(m4_dquote(m4_defn([m4_cr_all])), 2214 m4_defn([m4_cr_$1])))]) 2215 2216 2217 # m4_cr_not_letters 2218 # m4_cr_not_LETTERS 2219 # m4_cr_not_Letters 2220 # m4_cr_not_digits 2221 # m4_cr_not_alnum 2222 # m4_cr_not_symbols1 2223 # m4_cr_not_symbols2 2224 # ------------------ 2225 # Inverse character sets 2226 _m4_define_cr_not([letters]) 2227 _m4_define_cr_not([LETTERS]) 2228 _m4_define_cr_not([Letters]) 2229 _m4_define_cr_not([digits]) 2230 _m4_define_cr_not([alnum]) 2231 _m4_define_cr_not([symbols1]) 2232 _m4_define_cr_not([symbols2]) 2233 2234 2235 # m4_newline([STRING]) 2236 # -------------------- 2237 # Expands to a newline, possibly followed by STRING. Exists mostly for 2238 # formatting reasons. 2239 m4_define([m4_newline], [ 2240 $1]) 2241 2242 2243 # m4_re_escape(STRING) 2244 # -------------------- 2245 # Escape RE active characters in STRING. 2246 m4_define([m4_re_escape], 2247 [m4_bpatsubst([$1], 2248 [[][*+.?\^$]], [\\\&])]) 2249 2250 2251 # m4_re_string 2252 # ------------ 2253 # Regexp for `[a-zA-Z_0-9]*' 2254 # m4_dquote provides literal [] for the character class. 2255 m4_define([m4_re_string], 2256 m4_dquote(m4_defn([m4_cr_symbols2]))dnl 2257 [*]dnl 2258 ) 2259 2260 2261 # m4_re_word 2262 # ---------- 2263 # Regexp for `[a-zA-Z_][a-zA-Z_0-9]*' 2264 m4_define([m4_re_word], 2265 m4_dquote(m4_defn([m4_cr_symbols1]))dnl 2266 m4_defn([m4_re_string])dnl 2267 ) 2268 2269 2270 # m4_tolower(STRING) 2271 # m4_toupper(STRING) 2272 # ------------------ 2273 # These macros convert STRING to lowercase or uppercase. 2274 # 2275 # Rather than expand the m4_defn each time, we inline them up front. 2276 m4_define([m4_tolower], 2277 [m4_translit([[$1]], ]m4_dquote(m4_defn([m4_cr_LETTERS]))[, 2278 ]m4_dquote(m4_defn([m4_cr_letters]))[)]) 2279 m4_define([m4_toupper], 2280 [m4_translit([[$1]], ]m4_dquote(m4_defn([m4_cr_letters]))[, 2281 ]m4_dquote(m4_defn([m4_cr_LETTERS]))[)]) 2282 2283 2284 # m4_split(STRING, [REGEXP]) 2285 # -------------------------- 2286 # Split STRING into an m4 list of quoted elements. The elements are 2287 # quoted with [ and ]. Beginning spaces and end spaces *are kept*. 2288 # Use m4_strip to remove them. 2289 # 2290 # REGEXP specifies where to split. Default is [\t ]+. 2291 # 2292 # If STRING is empty, the result is an empty list. 2293 # 2294 # Pay attention to the m4_changequotes. When m4 reads the definition of 2295 # m4_split, it still has quotes set to [ and ]. Luckily, these are matched 2296 # in the macro body, so the definition is stored correctly. Use the same 2297 # alternate quotes as m4_noquote; it must be unlikely to appear in $1. 2298 # 2299 # Also, notice that $1 is quoted twice, since we want the result to 2300 # be quoted. Then you should understand that the argument of 2301 # patsubst is -=<{(STRING)}>=- (i.e., with additional -=<{( and )}>=-). 2302 # 2303 # This macro is safe on active symbols, i.e.: 2304 # m4_define(active, ACTIVE) 2305 # m4_split([active active ])end 2306 # => [active], [active], []end 2307 # 2308 # Optimize on regex of ` ' (space), since m4_foreach_w already guarantees 2309 # that the list contains single space separators, and a common case is 2310 # splitting a single-element list. This macro is called frequently, 2311 # so avoid unnecessary dnl inside the definition. 2312 m4_define([m4_split], 2313 [m4_if([$1], [], [], 2314 [$2], [ ], [m4_if(m4_index([$1], [ ]), [-1], [[[$1]]], 2315 [_$0([$1], [$2], [, ])])], 2316 [$2], [], [_$0([$1], [[ ]+], [, ])], 2317 [_$0([$1], [$2], [, ])])]) 2318 2319 m4_define([_m4_split], 2320 [m4_changequote([-=<{(],[)}>=-])]dnl 2321 [[m4_bpatsubst(-=<{(-=<{($1)}>=-)}>=-, -=<{($2)}>=-, 2322 -=<{(]$3[)}>=-)]m4_changequote([, ])]) 2323 2324 2325 # m4_chomp(STRING) 2326 # m4_chomp_all(STRING) 2327 # -------------------- 2328 # Return STRING quoted, but without a trailing newline. m4_chomp 2329 # removes at most one newline, while m4_chomp_all removes all 2330 # consecutive trailing newlines. Embedded newlines are not touched, 2331 # and a trailing backslash-newline leaves just a trailing backslash. 2332 # 2333 # m4_bregexp is slower than m4_index, and we don't always want to 2334 # remove all newlines; hence the two variants. We massage characters 2335 # to give a nicer pattern to match, particularly since m4_bregexp is 2336 # line-oriented. Both versions must guarantee a match, to avoid bugs 2337 # with precision -1 in m4_format in older m4. 2338 m4_define([m4_chomp], 2339 [m4_format([[%.*s]], m4_index(m4_translit([[$1]], [ 2340 /.], [/ ])[./.], [/.]), [$1])]) 2341 2342 m4_define([m4_chomp_all], 2343 [m4_format([[%.*s]], m4_bregexp(m4_translit([[$1]], [ 2344 /], [/ ]), [/*$]), [$1])]) 2345 2346 2347 # m4_flatten(STRING) 2348 # ------------------ 2349 # If STRING contains end of lines, replace them with spaces. If there 2350 # are backslashed end of lines, remove them. This macro is safe with 2351 # active symbols. 2352 # m4_define(active, ACTIVE) 2353 # m4_flatten([active 2354 # act\ 2355 # ive])end 2356 # => active activeend 2357 # 2358 # In m4, m4_bpatsubst is expensive, so first check for a newline. 2359 m4_define([m4_flatten], 2360 [m4_if(m4_index([$1], [ 2361 ]), [-1], [[$1]], 2362 [m4_translit(m4_bpatsubst([[[$1]]], [\\ 2363 ]), [ 2364 ], [ ])])]) 2365 2366 2367 # m4_strip(STRING) 2368 # ---------------- 2369 # Expands into STRING with tabs and spaces singled out into a single 2370 # space, and removing leading and trailing spaces. 2371 # 2372 # This macro is robust to active symbols. 2373 # m4_define(active, ACTIVE) 2374 # m4_strip([ active <tab> <tab>active ])end 2375 # => active activeend 2376 # 2377 # First, notice that we guarantee trailing space. Why? Because regular 2378 # expressions are greedy, and `.* ?' would always group the space into the 2379 # .* portion. The algorithm is simpler by avoiding `?' at the end. The 2380 # algorithm correctly strips everything if STRING is just ` '. 2381 # 2382 # Then notice the second pattern: it is in charge of removing the 2383 # leading/trailing spaces. Why not just `[^ ]'? Because they are 2384 # applied to over-quoted strings, i.e. more or less [STRING], due 2385 # to the limitations of m4_bpatsubsts. So the leading space in STRING 2386 # is the *second* character; equally for the trailing space. 2387 m4_define([m4_strip], 2388 [m4_bpatsubsts([$1 ], 2389 [[ ]+], [ ], 2390 [^. ?\(.*\) .$], [[[\1]]])]) 2391 2392 2393 # m4_normalize(STRING) 2394 # -------------------- 2395 # Apply m4_flatten and m4_strip to STRING. 2396 # 2397 # The argument is quoted, so that the macro is robust to active symbols: 2398 # 2399 # m4_define(active, ACTIVE) 2400 # m4_normalize([ act\ 2401 # ive 2402 # active ])end 2403 # => active activeend 2404 2405 m4_define([m4_normalize], 2406 [m4_strip(m4_flatten([$1]))]) 2407 2408 2409 2410 # m4_join(SEP, ARG1, ARG2...) 2411 # --------------------------- 2412 # Produce ARG1SEPARG2...SEPARGn. Avoid back-to-back SEP when a given ARG 2413 # is the empty string. No expansion is performed on SEP or ARGs. 2414 # 2415 # Since the number of arguments to join can be arbitrarily long, we 2416 # want to avoid having more than one $@ in the macro definition; 2417 # otherwise, the expansion would require twice the memory of the already 2418 # long list. Hence, m4_join merely looks for the first non-empty element, 2419 # and outputs just that element; while _m4_join looks for all non-empty 2420 # elements, and outputs them following a separator. The final trick to 2421 # note is that we decide between recursing with $0 or _$0 based on the 2422 # nested m4_if ending with `_'. 2423 # 2424 # Please keep foreach.m4 in sync with any adjustments made here. 2425 m4_define([m4_join], 2426 [m4_if([$#], [1], [], 2427 [$#], [2], [[$2]], 2428 [m4_if([$2], [], [], [[$2]_])$0([$1], m4_shift2($@))])]) 2429 m4_define([_m4_join], 2430 [m4_if([$#$2], [2], [], 2431 [m4_if([$2], [], [], [[$1$2]])$0([$1], m4_shift2($@))])]) 2432 2433 # m4_joinall(SEP, ARG1, ARG2...) 2434 # ------------------------------ 2435 # Produce ARG1SEPARG2...SEPARGn. An empty ARG results in back-to-back SEP. 2436 # No expansion is performed on SEP or ARGs. 2437 # 2438 # Please keep foreach.m4 in sync with any adjustments made here. 2439 m4_define([m4_joinall], [[$2]_$0([$1], m4_shift($@))]) 2440 m4_define([_m4_joinall], 2441 [m4_if([$#], [2], [], [[$1$3]$0([$1], m4_shift2($@))])]) 2442 2443 # m4_combine([SEPARATOR], PREFIX-LIST, [INFIX], SUFFIX...) 2444 # -------------------------------------------------------- 2445 # Produce the pairwise combination of every element in the quoted, 2446 # comma-separated PREFIX-LIST with every element from the SUFFIX arguments. 2447 # Each pair is joined with INFIX, and pairs are separated by SEPARATOR. 2448 # No expansion occurs on SEPARATOR, INFIX, or elements of either list. 2449 # 2450 # For example: 2451 # m4_combine([, ], [[a], [b], [c]], [-], [1], [2], [3]) 2452 # => a-1, a-2, a-3, b-1, b-2, b-3, c-1, c-2, c-3 2453 # 2454 # This definition is a bit hairy; the thing to realize is that we want 2455 # to construct m4_map_args_sep([[prefix$3]], [], [[$1]], m4_shift3($@)) 2456 # as the inner loop, using each prefix generated by the outer loop, 2457 # and without recalculating m4_shift3 every outer iteration. 2458 m4_define([m4_combine], 2459 [m4_if([$2], [], [], m4_eval([$# > 3]), [1], 2460 [m4_map_args_sep([m4_map_args_sep(m4_dquote(], [)[[$3]], [], [[$1]],]]]dnl 2461 [m4_dquote(m4_dquote(m4_shift3($@)))[[)], [[$1]], $2)])]) 2462 2463 2464 # m4_append(MACRO-NAME, STRING, [SEPARATOR]) 2465 # ------------------------------------------ 2466 # Redefine MACRO-NAME to hold its former content plus `SEPARATOR`'STRING' 2467 # at the end. It is valid to use this macro with MACRO-NAME undefined, 2468 # in which case no SEPARATOR is added. Be aware that the criterion is 2469 # `not being defined', and not `not being empty'. 2470 # 2471 # Note that neither STRING nor SEPARATOR are expanded here; rather, when 2472 # you expand MACRO-NAME, they will be expanded at that point in time. 2473 # 2474 # This macro is robust to active symbols. It can be used to grow 2475 # strings. 2476 # 2477 # | m4_define(active, ACTIVE)dnl 2478 # | m4_append([sentence], [This is an])dnl 2479 # | m4_append([sentence], [ active ])dnl 2480 # | m4_append([sentence], [symbol.])dnl 2481 # | sentence 2482 # | m4_undefine([active])dnl 2483 # | sentence 2484 # => This is an ACTIVE symbol. 2485 # => This is an active symbol. 2486 # 2487 # It can be used to define hooks. 2488 # 2489 # | m4_define(active, ACTIVE)dnl 2490 # | m4_append([hooks], [m4_define([act1], [act2])])dnl 2491 # | m4_append([hooks], [m4_define([act2], [active])])dnl 2492 # | m4_undefine([active])dnl 2493 # | act1 2494 # | hooks 2495 # | act1 2496 # => act1 2497 # => 2498 # => active 2499 # 2500 # It can also be used to create lists, although this particular usage was 2501 # broken prior to autoconf 2.62. 2502 # | m4_append([list], [one], [, ])dnl 2503 # | m4_append([list], [two], [, ])dnl 2504 # | m4_append([list], [three], [, ])dnl 2505 # | list 2506 # | m4_dquote(list) 2507 # => one, two, three 2508 # => [one],[two],[three] 2509 # 2510 # Note that m4_append can benefit from amortized O(n) m4 behavior, if 2511 # the underlying m4 implementation is smart enough to avoid copying existing 2512 # contents when enlarging a macro's definition into any pre-allocated storage 2513 # (m4 1.4.x unfortunately does not implement this optimization). We do 2514 # not implement m4_prepend, since it is inherently O(n^2) (pre-allocated 2515 # storage only occurs at the end of a macro, so the existing contents must 2516 # always be moved). 2517 # 2518 # Use _m4_defn for speed. 2519 m4_define([m4_append], 2520 [m4_define([$1], m4_ifdef([$1], [_m4_defn([$1])[$3]])[$2])]) 2521 2522 2523 # m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR], [IF-UNIQ], [IF-DUP]) 2524 # -------------------------------------------------------------------- 2525 # Like `m4_append', but append only if not yet present. Additionally, 2526 # expand IF-UNIQ if STRING was appended, or IF-DUP if STRING was already 2527 # present. Also, warn if SEPARATOR is not empty and occurs within STRING, 2528 # as the algorithm no longer guarantees uniqueness. 2529 # 2530 # Note that while m4_append can be O(n) (depending on the quality of the 2531 # underlying M4 implementation), m4_append_uniq is inherently O(n^2) 2532 # because each append operation searches the entire string. 2533 m4_define([m4_append_uniq], 2534 [m4_ifval([$3], [m4_if(m4_index([$2], [$3]), [-1], [], 2535 [m4_warn([syntax], 2536 [$0: `$2' contains `$3'])])])_$0($@)]) 2537 m4_define([_m4_append_uniq], 2538 [m4_ifdef([$1], 2539 [m4_if(m4_index([$3]_m4_defn([$1])[$3], [$3$2$3]), [-1], 2540 [m4_append([$1], [$2], [$3])$4], [$5])], 2541 [m4_define([$1], [$2])$4])]) 2542 2543 # m4_append_uniq_w(MACRO-NAME, STRINGS) 2544 # ------------------------------------- 2545 # For each of the words in the whitespace separated list STRINGS, append 2546 # only the unique strings to the definition of MACRO-NAME. 2547 # 2548 # Use _m4_defn for speed. 2549 m4_define([m4_append_uniq_w], 2550 [m4_map_args_w([$2], [_m4_append_uniq([$1],], [, [ ])])]) 2551 2552 2553 # m4_escape(STRING) 2554 # ----------------- 2555 # Output quoted STRING, but with embedded #, $, [ and ] turned into 2556 # quadrigraphs. 2557 # 2558 # It is faster to check if STRING is already good using m4_translit 2559 # than to blindly perform four m4_bpatsubst. 2560 # 2561 # Because the translit is stripping quotes, it must also neutralize 2562 # anything that might be in a macro name, as well as comments, commas, 2563 # and parentheses. All the problem characters are unified so that a 2564 # single m4_index can scan the result. 2565 # 2566 # Rather than expand m4_defn every time m4_escape is expanded, we 2567 # inline its expansion up front. 2568 m4_define([m4_escape], 2569 [m4_if(m4_index(m4_translit([$1], 2570 [[]#,()]]m4_dquote(m4_defn([m4_cr_symbols2]))[, [$$$]), [$]), 2571 [-1], [m4_echo], [_$0])([$1])]) 2572 2573 m4_define([_m4_escape], 2574 [m4_changequote([-=<{(],[)}>=-])]dnl 2575 [m4_bpatsubst(m4_bpatsubst(m4_bpatsubst(m4_bpatsubst( 2576 -=<{(-=<{(-=<{(-=<{(-=<{($1)}>=-)}>=-)}>=-)}>=-)}>=-, 2577 -=<{(#)}>=-, -=<{(@%:@)}>=-), 2578 -=<{(\[)}>=-, -=<{(@<:@)}>=-), 2579 -=<{(\])}>=-, -=<{(@:>@)}>=-), 2580 -=<{(\$)}>=-, -=<{(@S|@)}>=-)m4_changequote([,])]) 2581 2582 2583 # m4_text_wrap(STRING, [PREFIX], [FIRST-PREFIX], [WIDTH]) 2584 # ------------------------------------------------------- 2585 # Expands into STRING wrapped to hold in WIDTH columns (default = 79). 2586 # If PREFIX is given, each line is prefixed with it. If FIRST-PREFIX is 2587 # specified, then the first line is prefixed with it. As a special case, 2588 # if the length of FIRST-PREFIX is greater than that of PREFIX, then 2589 # FIRST-PREFIX will be left alone on the first line. 2590 # 2591 # No expansion occurs on the contents STRING, PREFIX, or FIRST-PREFIX, 2592 # although quadrigraphs are correctly recognized. More precisely, 2593 # you may redefine m4_qlen to recognize whatever escape sequences that 2594 # you will post-process. 2595 # 2596 # Typical outputs are: 2597 # 2598 # m4_text_wrap([Short string */], [ ], [/* ], 20) 2599 # => /* Short string */ 2600 # 2601 # m4_text_wrap([Much longer string */], [ ], [/* ], 20) 2602 # => /* Much longer 2603 # => string */ 2604 # 2605 # m4_text_wrap([Short doc.], [ ], [ --short ], 30) 2606 # => --short Short doc. 2607 # 2608 # m4_text_wrap([Short doc.], [ ], [ --too-wide ], 30) 2609 # => --too-wide 2610 # => Short doc. 2611 # 2612 # m4_text_wrap([Super long documentation.], [ ], [ --too-wide ], 30) 2613 # => --too-wide 2614 # => Super long 2615 # => documentation. 2616 # 2617 # FIXME: there is no checking of a longer PREFIX than WIDTH, but do 2618 # we really want to bother with people trying each single corner 2619 # of a software? 2620 # 2621 # This macro does not leave a trailing space behind the last word of a line, 2622 # which complicates it a bit. The algorithm is otherwise stupid and simple: 2623 # all the words are preceded by m4_Separator which is defined to empty for 2624 # the first word, and then ` ' (single space) for all the others. 2625 # 2626 # The algorithm uses a helper that uses $2 through $4 directly, rather than 2627 # using local variables, to avoid m4_defn overhead, or expansion swallowing 2628 # any $. It also bypasses m4_popdef overhead with _m4_popdef since no user 2629 # macro expansion occurs in the meantime. Also, the definition is written 2630 # with m4_do, to avoid time wasted on dnl during expansion (since this is 2631 # already a time-consuming macro). 2632 m4_define([m4_text_wrap], 2633 [_$0(m4_escape([$1]), [$2], m4_default_quoted([$3], [$2]), 2634 m4_default_quoted([$4], [79]))]) 2635 2636 m4_define([_m4_text_wrap], 2637 m4_do(dnl set up local variables, to avoid repeated calculations 2638 [[m4_pushdef([m4_Indent], m4_qlen([$2]))]], 2639 [[m4_pushdef([m4_Cursor], m4_qlen([$3]))]], 2640 [[m4_pushdef([m4_Separator], [m4_define([m4_Separator], [ ])])]], 2641 dnl expand the first prefix, then check its length vs. regular prefix 2642 dnl same length: nothing special 2643 dnl prefix1 longer: output on line by itself, and reset cursor 2644 dnl prefix1 shorter: pad to length of prefix, and reset cursor 2645 [[[$3]m4_cond([m4_Cursor], m4_Indent, [], 2646 [m4_eval(m4_Cursor > m4_Indent)], [1], [ 2647 [$2]m4_define([m4_Cursor], m4_Indent)], 2648 [m4_format([%*s], m4_max([0], 2649 m4_eval(m4_Indent - m4_Cursor)), [])m4_define([m4_Cursor], m4_Indent)])]], 2650 dnl now, for each word, compute the cursor after the word is output, then 2651 dnl check if the cursor would exceed the wrap column 2652 dnl if so, reset cursor, and insert newline and prefix 2653 dnl if not, insert the separator (usually a space) 2654 dnl either way, insert the word 2655 [[m4_map_args_w([$1], [$0_word(], [, [$2], [$4])])]], 2656 dnl finally, clean up the local variables 2657 [[_m4_popdef([m4_Separator], [m4_Cursor], [m4_Indent])]])) 2658 2659 m4_define([_m4_text_wrap_word], 2660 [m4_define([m4_Cursor], m4_eval(m4_Cursor + m4_qlen([$1]) + 1))]dnl 2661 [m4_if(m4_eval(m4_Cursor > ([$3])), 2662 [1], [m4_define([m4_Cursor], m4_eval(m4_Indent + m4_qlen([$1]) + 1)) 2663 [$2]], 2664 [m4_Separator[]])[$1]]) 2665 2666 # m4_text_box(MESSAGE, [FRAME-CHARACTER = `-']) 2667 # --------------------------------------------- 2668 # Turn MESSAGE into: 2669 # ## ------- ## 2670 # ## MESSAGE ## 2671 # ## ------- ## 2672 # using FRAME-CHARACTER in the border. 2673 # 2674 # Quadrigraphs are correctly recognized. More precisely, you may 2675 # redefine m4_qlen to recognize whatever escape sequences that you 2676 # will post-process. 2677 m4_define([m4_text_box], 2678 [m4_pushdef([m4_Border], 2679 m4_translit(m4_format([[[%*s]]], m4_decr(m4_qlen(_m4_expand([$1 2680 ]))), []), [ ], m4_default_quoted([$2], [-])))]dnl 2681 [[##] _m4_defn([m4_Border]) [##] 2682 [##] $1 [##] 2683 [##] _m4_defn([m4_Border]) [##]_m4_popdef([m4_Border])]) 2684 2685 2686 # m4_qlen(STRING) 2687 # --------------- 2688 # Expands to the length of STRING after autom4te converts all quadrigraphs. 2689 # 2690 # If you use some other means of post-processing m4 output rather than 2691 # autom4te, then you may redefine this macro to recognize whatever 2692 # escape sequences your post-processor will handle. For that matter, 2693 # m4_define([m4_qlen], m4_defn([m4_len])) is sufficient if you don't 2694 # do any post-processing. 2695 # 2696 # Avoid bpatsubsts for the common case of no quadrigraphs. Cache 2697 # results, as configure scripts tend to ask about lengths of common 2698 # strings like `/*' and `*/' rather frequently. Minimize the number 2699 # of times that $1 occurs in m4_qlen, so there is less text to parse 2700 # on a cache hit. 2701 m4_define([m4_qlen], 2702 [m4_ifdef([$0-$1], [_m4_defn([$0-]], [_$0(])[$1])]) 2703 m4_define([_m4_qlen], 2704 [m4_define([m4_qlen-$1], 2705 m4_if(m4_index([$1], [@]), [-1], [m4_len([$1])], 2706 [m4_len(m4_bpatsubst([[$1]], 2707 [@\(\(<:\|:>\|S|\|%:\|\{:\|:\}\)\(@\)\|&t@\)], 2708 [\3]))]))_m4_defn([m4_qlen-$1])]) 2709 2710 # m4_copyright_condense(TEXT) 2711 # --------------------------- 2712 # Condense the copyright notice in TEXT to only display the final 2713 # year, wrapping the results to fit in 80 columns. 2714 m4_define([m4_copyright_condense], 2715 [m4_text_wrap(m4_bpatsubst(m4_flatten([[$1]]), 2716 [(C)[- ,0-9]*\([1-9][0-9][0-9][0-9]\)], [(C) \1]))]) 2717 2718 ## ----------------------- ## 2719 ## 13. Number processing. ## 2720 ## ----------------------- ## 2721 2722 # m4_cmp(A, B) 2723 # ------------ 2724 # Compare two integer expressions. 2725 # A < B -> -1 2726 # A = B -> 0 2727 # A > B -> 1 2728 m4_define([m4_cmp], 2729 [m4_eval((([$1]) > ([$2])) - (([$1]) < ([$2])))]) 2730 2731 2732 # m4_list_cmp(A, B) 2733 # ----------------- 2734 # 2735 # Compare the two lists of integer expressions A and B. For instance: 2736 # m4_list_cmp([1, 0], [1]) -> 0 2737 # m4_list_cmp([1, 0], [1, 0]) -> 0 2738 # m4_list_cmp([1, 2], [1, 0]) -> 1 2739 # m4_list_cmp([1, 2, 3], [1, 2]) -> 1 2740 # m4_list_cmp([1, 2, -3], [1, 2]) -> -1 2741 # m4_list_cmp([1, 0], [1, 2]) -> -1 2742 # m4_list_cmp([1], [1, 2]) -> -1 2743 # m4_define([xa], [oops])dnl 2744 # m4_list_cmp([[0xa]], [5+5]) -> 0 2745 # 2746 # Rather than face the overhead of m4_case, we use a helper function whose 2747 # expansion includes the name of the macro to invoke on the tail, either 2748 # m4_ignore or m4_unquote. This is particularly useful when comparing 2749 # long lists, since less text is being expanded for deciding when to end 2750 # recursion. The recursion is between a pair of macros that alternate 2751 # which list is trimmed by one element; this is more efficient than 2752 # calling m4_cdr on both lists from a single macro. Guarantee exactly 2753 # one expansion of both lists' side effects. 2754 # 2755 # Please keep foreach.m4 in sync with any adjustments made here. 2756 m4_define([m4_list_cmp], 2757 [_$0_raw(m4_dquote($1), m4_dquote($2))]) 2758 2759 m4_define([_m4_list_cmp_raw], 2760 [m4_if([$1], [$2], [0], [_m4_list_cmp_1([$1], $2)])]) 2761 2762 m4_define([_m4_list_cmp], 2763 [m4_if([$1], [], [0m4_ignore], [$2], [0], [m4_unquote], [$2m4_ignore])]) 2764 2765 m4_define([_m4_list_cmp_1], 2766 [_m4_list_cmp_2([$2], [m4_shift2($@)], $1)]) 2767 2768 m4_define([_m4_list_cmp_2], 2769 [_m4_list_cmp([$1$3], m4_cmp([$3+0], [$1+0]))( 2770 [_m4_list_cmp_1(m4_dquote(m4_shift3($@)), $2)])]) 2771 2772 # m4_max(EXPR, ...) 2773 # m4_min(EXPR, ...) 2774 # ----------------- 2775 # Return the decimal value of the maximum (or minimum) in a series of 2776 # integer expressions. 2777 # 2778 # M4 1.4.x doesn't provide ?:. Hence this huge m4_eval. Avoid m4_eval 2779 # if both arguments are identical, but be aware of m4_max(0xa, 10) (hence 2780 # the use of <=, not just <, in the second multiply). 2781 # 2782 # Please keep foreach.m4 in sync with any adjustments made here. 2783 m4_define([m4_max], 2784 [m4_if([$#], [0], [m4_fatal([too few arguments to $0])], 2785 [$#], [1], [m4_eval([$1])], 2786 [$#$1], [2$2], [m4_eval([$1])], 2787 [$#], [2], [_$0($@)], 2788 [_m4_minmax([_$0], $@)])]) 2789 2790 m4_define([_m4_max], 2791 [m4_eval((([$1]) > ([$2])) * ([$1]) + (([$1]) <= ([$2])) * ([$2]))]) 2792 2793 m4_define([m4_min], 2794 [m4_if([$#], [0], [m4_fatal([too few arguments to $0])], 2795 [$#], [1], [m4_eval([$1])], 2796 [$#$1], [2$2], [m4_eval([$1])], 2797 [$#], [2], [_$0($@)], 2798 [_m4_minmax([_$0], $@)])]) 2799 2800 m4_define([_m4_min], 2801 [m4_eval((([$1]) < ([$2])) * ([$1]) + (([$1]) >= ([$2])) * ([$2]))]) 2802 2803 # _m4_minmax(METHOD, ARG1, ARG2...) 2804 # --------------------------------- 2805 # Common recursion code for m4_max and m4_min. METHOD must be _m4_max 2806 # or _m4_min, and there must be at least two arguments to combine. 2807 # 2808 # Please keep foreach.m4 in sync with any adjustments made here. 2809 m4_define([_m4_minmax], 2810 [m4_if([$#], [3], [$1([$2], [$3])], 2811 [$0([$1], $1([$2], [$3]), m4_shift3($@))])]) 2812 2813 2814 # m4_sign(A) 2815 # ---------- 2816 # The sign of the integer expression A. 2817 m4_define([m4_sign], 2818 [m4_eval((([$1]) > 0) - (([$1]) < 0))]) 2819 2820 2821 2822 ## ------------------------ ## 2823 ## 14. Version processing. ## 2824 ## ------------------------ ## 2825 2826 2827 # m4_version_unletter(VERSION) 2828 # ---------------------------- 2829 # Normalize beta version numbers with letters to numeric expressions, which 2830 # can then be handed to m4_eval for the purpose of comparison. 2831 # 2832 # Nl -> (N+1).-1.(l#) 2833 # 2834 # for example: 2835 # [2.14a] -> [0,2,14+1,-1,[0r36:a]] -> 2.15.-1.10 2836 # [2.14b] -> [0,2,15+1,-1,[0r36:b]] -> 2.15.-1.11 2837 # [2.61aa.b] -> [0,2.61,1,-1,[0r36:aa],+1,-1,[0r36:b]] -> 2.62.-1.370.1.-1.11 2838 # [08] -> [0,[0r10:0]8] -> 8 2839 # 2840 # This macro expects reasonable version numbers, but can handle double 2841 # letters and does not expand any macros. Original version strings can 2842 # use both `.' and `-' separators. 2843 # 2844 # Inline constant expansions, to avoid m4_defn overhead. 2845 # _m4_version_unletter is the real workhorse used by m4_version_compare, 2846 # but since [0r36:a] and commas are less readable than 10 and dots, we 2847 # provide a wrapper for human use. 2848 m4_define([m4_version_unletter], 2849 [m4_substr(m4_map_args([.m4_eval], m4_unquote(_$0([$1]))), [3])]) 2850 m4_define([_m4_version_unletter], 2851 [m4_bpatsubst(m4_bpatsubst(m4_translit([[[[0,$1]]]], [.-], [,,]),]dnl 2852 m4_dquote(m4_dquote(m4_defn([m4_cr_Letters])))[[+], 2853 [+1,-1,[0r36:\&]]), [,0], [,[0r10:0]])]) 2854 2855 2856 # m4_version_compare(VERSION-1, VERSION-2) 2857 # ---------------------------------------- 2858 # Compare the two version numbers and expand into 2859 # -1 if VERSION-1 < VERSION-2 2860 # 0 if = 2861 # 1 if > 2862 # 2863 # Since _m4_version_unletter does not output side effects, we can 2864 # safely bypass the overhead of m4_version_cmp. 2865 m4_define([m4_version_compare], 2866 [_m4_list_cmp_raw(_m4_version_unletter([$1]), _m4_version_unletter([$2]))]) 2867 2868 2869 # m4_PACKAGE_NAME 2870 # m4_PACKAGE_TARNAME 2871 # m4_PACKAGE_VERSION 2872 # m4_PACKAGE_STRING 2873 # m4_PACKAGE_BUGREPORT 2874 # -------------------- 2875 # If m4sugar/version.m4 is present, then define version strings. This 2876 # file is optional, provided by Autoconf but absent in Bison. 2877 m4_sinclude([m4sugar/version.m4]) 2878 2879 2880 # m4_version_prereq(VERSION, [IF-OK], [IF-NOT = FAIL]) 2881 # ---------------------------------------------------- 2882 # Check this Autoconf version against VERSION. 2883 m4_define([m4_version_prereq], 2884 m4_ifdef([m4_PACKAGE_VERSION], 2885 [[m4_if(m4_version_compare(]m4_dquote(m4_defn([m4_PACKAGE_VERSION]))[, [$1]), 2886 [-1], 2887 [m4_default([$3], 2888 [m4_fatal([Autoconf version $1 or higher is required], 2889 [63])])], 2890 [$2])]], 2891 [[m4_fatal([m4sugar/version.m4 not found])]])) 2892 2893 2894 ## ------------------ ## 2895 ## 15. Set handling. ## 2896 ## ------------------ ## 2897 2898 # Autoconf likes to create arbitrarily large sets; for example, as of 2899 # this writing, the configure.ac for coreutils tracks a set of more 2900 # than 400 AC_SUBST. How do we track all of these set members, 2901 # without introducing duplicates? We could use m4_append_uniq, with 2902 # the set NAME residing in the contents of the macro NAME. 2903 # Unfortunately, m4_append_uniq is quadratic for set creation, because 2904 # it costs O(n) to search the string for each of O(n) insertions; not 2905 # to mention that with m4 1.4.x, even using m4_append is slow, costing 2906 # O(n) rather than O(1) per insertion. Other set operations, not used 2907 # by Autoconf but still possible by manipulation of the definition 2908 # tracked in macro NAME, include O(n) deletion of one element and O(n) 2909 # computation of set size. Because the set is exposed to the user via 2910 # the definition of a single macro, we cannot cache any data about the 2911 # set without risking the cache being invalidated by the user 2912 # redefining NAME. 2913 # 2914 # Can we do better? Yes, because m4 gives us an O(1) search function 2915 # for free: ifdef. Additionally, even m4 1.4.x gives us an O(1) 2916 # insert operation for free: pushdef. But to use these, we must 2917 # represent the set via a group of macros; to keep the set consistent, 2918 # we must hide the set so that the user can only manipulate it through 2919 # accessor macros. The contents of the set are maintained through two 2920 # access points; _m4_set([name]) is a pushdef stack of values in the 2921 # set, useful for O(n) traversal of the set contents; while the 2922 # existence of _m4_set([name],value) with no particular value is 2923 # useful for O(1) querying of set membership. And since the user 2924 # cannot externally manipulate the set, we are free to add additional 2925 # caching macros for other performance improvements. Deletion can be 2926 # O(1) per element rather than O(n), by reworking the definition of 2927 # _m4_set([name],value) to be 0 or 1 based on current membership, and 2928 # adding _m4_set_cleanup(name) to defer the O(n) cleanup of 2929 # _m4_set([name]) until we have another reason to do an O(n) 2930 # traversal. The existence of _m4_set_cleanup(name) can then be used 2931 # elsewhere to determine if we must dereference _m4_set([name],value), 2932 # or assume that definition implies set membership. Finally, size can 2933 # be tracked in an O(1) fashion with _m4_set_size(name). 2934 # 2935 # The quoting in _m4_set([name],value) is chosen so that there is no 2936 # ambiguity with a set whose name contains a comma, and so that we can 2937 # supply the value via _m4_defn([_m4_set([name])]) without needing any 2938 # quote manipulation. 2939 2940 # m4_set_add(SET, VALUE, [IF-UNIQ], [IF-DUP]) 2941 # ------------------------------------------- 2942 # Add VALUE as an element of SET. Expand IF-UNIQ on the first 2943 # addition, and IF-DUP if it is already in the set. Addition of one 2944 # element is O(1), such that overall set creation is O(n). 2945 # 2946 # We do not want to add a duplicate for a previously deleted but 2947 # unpruned element, but it is just as easy to check existence directly 2948 # as it is to query _m4_set_cleanup($1). 2949 m4_define([m4_set_add], 2950 [m4_ifdef([_m4_set([$1],$2)], 2951 [m4_if(m4_indir([_m4_set([$1],$2)]), [0], 2952 [m4_define([_m4_set([$1],$2)], 2953 [1])_m4_set_size([$1], [m4_incr])$3], [$4])], 2954 [m4_define([_m4_set([$1],$2)], 2955 [1])m4_pushdef([_m4_set([$1])], 2956 [$2])_m4_set_size([$1], [m4_incr])$3])]) 2957 2958 # m4_set_add_all(SET, VALUE...) 2959 # ----------------------------- 2960 # Add each VALUE into SET. This is O(n) in the number of VALUEs, and 2961 # can be faster than calling m4_set_add for each VALUE. 2962 # 2963 # Implement two recursion helpers; the check variant is slower but 2964 # handles the case where an element has previously been removed but 2965 # not pruned. The recursion helpers ignore their second argument, so 2966 # that we can use the faster m4_shift2 and 2 arguments, rather than 2967 # _m4_shift2 and one argument, as the signal to end recursion. 2968 # 2969 # Please keep foreach.m4 in sync with any adjustments made here. 2970 m4_define([m4_set_add_all], 2971 [m4_define([_m4_set_size($1)], m4_eval(m4_set_size([$1]) 2972 + m4_len(m4_ifdef([_m4_set_cleanup($1)], [_$0_check], [_$0])([$1], $@))))]) 2973 2974 m4_define([_m4_set_add_all], 2975 [m4_if([$#], [2], [], 2976 [m4_ifdef([_m4_set([$1],$3)], [], 2977 [m4_define([_m4_set([$1],$3)], [1])m4_pushdef([_m4_set([$1])], 2978 [$3])-])$0([$1], m4_shift2($@))])]) 2979 2980 m4_define([_m4_set_add_all_check], 2981 [m4_if([$#], [2], [], 2982 [m4_set_add([$1], [$3])$0([$1], m4_shift2($@))])]) 2983 2984 # m4_set_contains(SET, VALUE, [IF-PRESENT], [IF-ABSENT]) 2985 # ------------------------------------------------------ 2986 # Expand IF-PRESENT if SET contains VALUE, otherwise expand IF-ABSENT. 2987 # This is always O(1). 2988 m4_define([m4_set_contains], 2989 [m4_ifdef([_m4_set_cleanup($1)], 2990 [m4_if(m4_ifdef([_m4_set([$1],$2)], 2991 [m4_indir([_m4_set([$1],$2)])], [0]), [1], [$3], [$4])], 2992 [m4_ifdef([_m4_set([$1],$2)], [$3], [$4])])]) 2993 2994 # m4_set_contents(SET, [SEP]) 2995 # --------------------------- 2996 # Expand to a single string containing all the elements in SET, 2997 # separated by SEP, without modifying SET. No provision is made for 2998 # disambiguating set elements that contain non-empty SEP as a 2999 # sub-string, or for recognizing a set that contains only the empty 3000 # string. Order of the output is not guaranteed. If any elements 3001 # have been previously removed from the set, this action will prune 3002 # the unused memory. This is O(n) in the size of the set before 3003 # pruning. 3004 # 3005 # Use _m4_popdef for speed. The existence of _m4_set_cleanup($1) 3006 # determines which version of _1 helper we use. 3007 m4_define([m4_set_contents], 3008 [m4_set_map_sep([$1], [], [], [[$2]])]) 3009 3010 # _m4_set_contents_1(SET) 3011 # _m4_set_contents_1c(SET) 3012 # _m4_set_contents_2(SET, [PRE], [POST], [SEP]) 3013 # --------------------------------------------- 3014 # Expand to a list of quoted elements currently in the set, each 3015 # surrounded by PRE and POST, and moving SEP in front of PRE on 3016 # recursion. To avoid nesting limit restrictions, the algorithm must 3017 # be broken into two parts; _1 destructively copies the stack in 3018 # reverse into _m4_set_($1), producing no output; then _2 3019 # destructively copies _m4_set_($1) back into the stack in reverse. 3020 # If no elements were deleted, then this visits the set in the order 3021 # that elements were inserted. Behavior is undefined if PRE/POST/SEP 3022 # tries to recursively list or modify SET in any way other than 3023 # calling m4_set_remove on the current element. Use _1 if all entries 3024 # in the stack are guaranteed to be in the set, and _1c to prune 3025 # removed entries. Uses _m4_defn and _m4_popdef for speed. 3026 m4_define([_m4_set_contents_1], 3027 [_m4_stack_reverse([_m4_set([$1])], [_m4_set_($1)])]) 3028 3029 m4_define([_m4_set_contents_1c], 3030 [m4_ifdef([_m4_set([$1])], 3031 [m4_set_contains([$1], _m4_defn([_m4_set([$1])]), 3032 [m4_pushdef([_m4_set_($1)], _m4_defn([_m4_set([$1])]))], 3033 [_m4_popdef([_m4_set([$1],]_m4_defn( 3034 [_m4_set([$1])])[)])])_m4_popdef([_m4_set([$1])])$0([$1])], 3035 [_m4_popdef([_m4_set_cleanup($1)])])]) 3036 3037 m4_define([_m4_set_contents_2], 3038 [_m4_stack_reverse([_m4_set_($1)], [_m4_set([$1])], 3039 [$2[]_m4_defn([_m4_set_($1)])$3], [$4[]])]) 3040 3041 # m4_set_delete(SET) 3042 # ------------------ 3043 # Delete all elements in SET, and reclaim any memory occupied by the 3044 # set. This is O(n) in the set size. 3045 # 3046 # Use _m4_defn and _m4_popdef for speed. 3047 m4_define([m4_set_delete], 3048 [m4_ifdef([_m4_set([$1])], 3049 [_m4_popdef([_m4_set([$1],]_m4_defn([_m4_set([$1])])[)], 3050 [_m4_set([$1])])$0([$1])], 3051 [m4_ifdef([_m4_set_cleanup($1)], 3052 [_m4_popdef([_m4_set_cleanup($1)])])m4_ifdef( 3053 [_m4_set_size($1)], 3054 [_m4_popdef([_m4_set_size($1)])])])]) 3055 3056 # m4_set_difference(SET1, SET2) 3057 # ----------------------------- 3058 # Produce a LIST of quoted elements that occur in SET1 but not SET2. 3059 # Output a comma prior to any elements, to distinguish the empty 3060 # string from no elements. This can be directly used as a series of 3061 # arguments, such as for m4_join, or wrapped inside quotes for use in 3062 # m4_foreach. Order of the output is not guaranteed. 3063 # 3064 # Short-circuit the idempotence relation. 3065 m4_define([m4_set_difference], 3066 [m4_if([$1], [$2], [], [m4_set_map_sep([$1], [_$0([$2],], [)])])]) 3067 3068 m4_define([_m4_set_difference], 3069 [m4_set_contains([$1], [$2], [], [,[$2]])]) 3070 3071 # m4_set_dump(SET, [SEP]) 3072 # ----------------------- 3073 # Expand to a single string containing all the elements in SET, 3074 # separated by SEP, then delete SET. In general, if you only need to 3075 # list the contents once, this is faster than m4_set_contents. No 3076 # provision is made for disambiguating set elements that contain 3077 # non-empty SEP as a sub-string. Order of the output is not 3078 # guaranteed. This is O(n) in the size of the set before pruning. 3079 # 3080 # Use _m4_popdef for speed. Use existence of _m4_set_cleanup($1) to 3081 # decide if more expensive recursion is needed. 3082 m4_define([m4_set_dump], 3083 [m4_ifdef([_m4_set_size($1)], 3084 [_m4_popdef([_m4_set_size($1)])])m4_ifdef([_m4_set_cleanup($1)], 3085 [_$0_check], [_$0])([$1], [], [$2])]) 3086 3087 # _m4_set_dump(SET, [SEP], [PREP]) 3088 # _m4_set_dump_check(SET, [SEP], [PREP]) 3089 # -------------------------------------- 3090 # Print SEP and the current element, then delete the element and 3091 # recurse with empty SEP changed to PREP. The check variant checks 3092 # whether the element has been previously removed. Use _m4_defn and 3093 # _m4_popdef for speed. 3094 m4_define([_m4_set_dump], 3095 [m4_ifdef([_m4_set([$1])], 3096 [[$2]_m4_defn([_m4_set([$1])])_m4_popdef([_m4_set([$1],]_m4_defn( 3097 [_m4_set([$1])])[)], [_m4_set([$1])])$0([$1], [$2$3])])]) 3098 3099 m4_define([_m4_set_dump_check], 3100 [m4_ifdef([_m4_set([$1])], 3101 [m4_set_contains([$1], _m4_defn([_m4_set([$1])]), 3102 [[$2]_m4_defn([_m4_set([$1])])])_m4_popdef( 3103 [_m4_set([$1],]_m4_defn([_m4_set([$1])])[)], 3104 [_m4_set([$1])])$0([$1], [$2$3])], 3105 [_m4_popdef([_m4_set_cleanup($1)])])]) 3106 3107 # m4_set_empty(SET, [IF-EMPTY], [IF-ELEMENTS]) 3108 # -------------------------------------------- 3109 # Expand IF-EMPTY if SET has no elements, otherwise IF-ELEMENTS. 3110 m4_define([m4_set_empty], 3111 [m4_ifdef([_m4_set_size($1)], 3112 [m4_if(m4_indir([_m4_set_size($1)]), [0], [$2], [$3])], [$2])]) 3113 3114 # m4_set_foreach(SET, VAR, ACTION) 3115 # -------------------------------- 3116 # For each element of SET, define VAR to the element and expand 3117 # ACTION. ACTION should not recursively list SET's contents, add 3118 # elements to SET, nor delete any element from SET except the one 3119 # currently in VAR. The order that the elements are visited in is not 3120 # guaranteed. This is faster than the corresponding m4_foreach([VAR], 3121 # m4_indir([m4_dquote]m4_set_listc([SET])), [ACTION]) 3122 m4_define([m4_set_foreach], 3123 [m4_pushdef([$2])m4_set_map_sep([$1], [m4_define([$2],], [)$3])]) 3124 3125 # m4_set_intersection(SET1, SET2) 3126 # ------------------------------- 3127 # Produce a LIST of quoted elements that occur in both SET1 or SET2. 3128 # Output a comma prior to any elements, to distinguish the empty 3129 # string from no elements. This can be directly used as a series of 3130 # arguments, such as for m4_join, or wrapped inside quotes for use in 3131 # m4_foreach. Order of the output is not guaranteed. 3132 # 3133 # Iterate over the smaller set, and short-circuit the idempotence 3134 # relation. 3135 m4_define([m4_set_intersection], 3136 [m4_if([$1], [$2], [m4_set_listc([$1])], 3137 m4_eval(m4_set_size([$2]) < m4_set_size([$1])), [1], [$0([$2], [$1])], 3138 [m4_set_map_sep([$1], [_$0([$2],], [)])])]) 3139 3140 m4_define([_m4_set_intersection], 3141 [m4_set_contains([$1], [$2], [,[$2]])]) 3142 3143 # m4_set_list(SET) 3144 # m4_set_listc(SET) 3145 # ----------------- 3146 # Produce a LIST of quoted elements of SET. This can be directly used 3147 # as a series of arguments, such as for m4_join or m4_set_add_all, or 3148 # wrapped inside quotes for use in m4_foreach or m4_map. With 3149 # m4_set_list, there is no way to distinguish an empty set from a set 3150 # containing only the empty string; with m4_set_listc, a leading comma 3151 # is output if there are any elements. 3152 m4_define([m4_set_list], 3153 [m4_set_map_sep([$1], [], [], [,])]) 3154 3155 m4_define([m4_set_listc], 3156 [m4_set_map_sep([$1], [,])]) 3157 3158 # m4_set_map(SET, ACTION) 3159 # ----------------------- 3160 # For each element of SET, expand ACTION with a single argument of the 3161 # current element. ACTION should not recursively list SET's contents, 3162 # add elements to SET, nor delete any element from SET except the one 3163 # passed as an argument. The order that the elements are visited in 3164 # is not guaranteed. This is faster than either of the corresponding 3165 # m4_map_args([ACTION]m4_set_listc([SET])) 3166 # m4_set_foreach([SET], [VAR], [ACTION(m4_defn([VAR]))]) 3167 m4_define([m4_set_map], 3168 [m4_set_map_sep([$1], [$2(], [)])]) 3169 3170 # m4_set_map_sep(SET, [PRE], [POST], [SEP]) 3171 # ----------------------------------------- 3172 # For each element of SET, expand PRE[value]POST[], and expand SEP 3173 # between elements. 3174 m4_define([m4_set_map_sep], 3175 [m4_ifdef([_m4_set_cleanup($1)], [_m4_set_contents_1c], 3176 [_m4_set_contents_1])([$1])_m4_set_contents_2($@)]) 3177 3178 # m4_set_remove(SET, VALUE, [IF-PRESENT], [IF-ABSENT]) 3179 # ---------------------------------------------------- 3180 # If VALUE is an element of SET, delete it and expand IF-PRESENT. 3181 # Otherwise expand IF-ABSENT. Deleting a single value is O(1), 3182 # although it leaves memory occupied until the next O(n) traversal of 3183 # the set which will compact the set. 3184 # 3185 # Optimize if the element being removed is the most recently added, 3186 # since defining _m4_set_cleanup($1) slows down so many other macros. 3187 # In particular, this plays well with m4_set_foreach and m4_set_map. 3188 m4_define([m4_set_remove], 3189 [m4_set_contains([$1], [$2], [_m4_set_size([$1], 3190 [m4_decr])m4_if(_m4_defn([_m4_set([$1])]), [$2], 3191 [_m4_popdef([_m4_set([$1],$2)], [_m4_set([$1])])], 3192 [m4_define([_m4_set_cleanup($1)])m4_define( 3193 [_m4_set([$1],$2)], [0])])$3], [$4])]) 3194 3195 # m4_set_size(SET) 3196 # ---------------- 3197 # Expand to the number of elements currently in SET. This operation 3198 # is O(1), and thus more efficient than m4_count(m4_set_list([SET])). 3199 m4_define([m4_set_size], 3200 [m4_ifdef([_m4_set_size($1)], [m4_indir([_m4_set_size($1)])], [0])]) 3201 3202 # _m4_set_size(SET, ACTION) 3203 # ------------------------- 3204 # ACTION must be either m4_incr or m4_decr, and the size of SET is 3205 # changed accordingly. If the set is empty, ACTION must not be 3206 # m4_decr. 3207 m4_define([_m4_set_size], 3208 [m4_define([_m4_set_size($1)], 3209 m4_ifdef([_m4_set_size($1)], [$2(m4_indir([_m4_set_size($1)]))], 3210 [1]))]) 3211 3212 # m4_set_union(SET1, SET2) 3213 # ------------------------ 3214 # Produce a LIST of double quoted elements that occur in either SET1 3215 # or SET2, without duplicates. Output a comma prior to any elements, 3216 # to distinguish the empty string from no elements. This can be 3217 # directly used as a series of arguments, such as for m4_join, or 3218 # wrapped inside quotes for use in m4_foreach. Order of the output is 3219 # not guaranteed. 3220 # 3221 # We can rely on the fact that m4_set_listc prunes SET1, so we don't 3222 # need to check _m4_set([$1],element) for 0. Short-circuit the 3223 # idempotence relation. 3224 m4_define([m4_set_union], 3225 [m4_set_listc([$1])m4_if([$1], [$2], [], 3226 [m4_set_map_sep([$2], [_$0([$1],], [)])])]) 3227 3228 m4_define([_m4_set_union], 3229 [m4_ifdef([_m4_set([$1],$2)], [], [,[$2]])]) 3230 3231 3232 ## ------------------- ## 3233 ## 16. File handling. ## 3234 ## ------------------- ## 3235 3236 3237 # It is a real pity that M4 comes with no macros to bind a diversion 3238 # to a file. So we have to deal without, which makes us a lot more 3239 # fragile than we should. 3240 3241 3242 # m4_file_append(FILE-NAME, CONTENT) 3243 # ---------------------------------- 3244 m4_define([m4_file_append], 3245 [m4_syscmd([cat >>$1 <<_m4eof 3246 $2 3247 _m4eof 3248 ]) 3249 m4_if(m4_sysval, [0], [], 3250 [m4_fatal([$0: cannot write: $1])])]) 3251 3252 3253 3254 ## ------------------------ ## 3255 ## 17. Setting M4sugar up. ## 3256 ## ------------------------ ## 3257 3258 # _m4_divert_diversion should be defined. 3259 m4_divert_push([KILL]) 3260 3261 # m4_init 3262 # ------- 3263 # Initialize the m4sugar language. 3264 m4_define([m4_init], 3265 [# All the M4sugar macros start with `m4_', except `dnl' kept as is 3266 # for sake of simplicity. 3267 m4_pattern_forbid([^_?m4_]) 3268 m4_pattern_forbid([^dnl$]) 3269 3270 # If __m4_version__ is defined, we assume that we are being run by M4 3271 # 1.6 or newer, thus $@ recursion is linear, and debugmode(+do) 3272 # is available for faster checks of dereferencing undefined macros 3273 # and forcing dumpdef to print to stderr regardless of debugfile. 3274 # But if it is missing, we assume we are being run by M4 1.4.x, that 3275 # $@ recursion is quadratic, and that we need foreach-based 3276 # replacement macros. Also, m4 prior to 1.4.8 loses track of location 3277 # during m4wrap text; __line__ should never be 0. 3278 # 3279 # Use the raw builtin to avoid tripping up include tracing. 3280 # Meanwhile, avoid m4_copy, since it temporarily undefines m4_defn. 3281 m4_ifdef([__m4_version__], 3282 [m4_debugmode([+do]) 3283 m4_define([m4_defn], _m4_defn([_m4_defn])) 3284 m4_define([m4_dumpdef], _m4_defn([_m4_dumpdef])) 3285 m4_define([m4_popdef], _m4_defn([_m4_popdef])) 3286 m4_define([m4_undefine], _m4_defn([_m4_undefine]))], 3287 [m4_builtin([include], [m4sugar/foreach.m4]) 3288 m4_wrap_lifo([m4_if(__line__, [0], [m4_pushdef([m4_location], 3289 ]]m4_dquote(m4_dquote(m4_dquote(__file__:__line__)))[[)])])]) 3290 3291 # Rewrite the first entry of the diversion stack. 3292 m4_divert([KILL]) 3293 3294 # Check the divert push/pop perfect balance. 3295 # Some users are prone to also use m4_wrap to register last-minute 3296 # m4_divert_text; so after our diversion cleanups, we restore 3297 # KILL as the bottom of the diversion stack. 3298 m4_wrap([m4_popdef([_m4_divert_diversion])m4_ifdef( 3299 [_m4_divert_diversion], [m4_fatal([$0: unbalanced m4_divert_push: 3300 ]m4_divert_stack)])_m4_popdef([_m4_divert_stack])m4_divert_push([KILL])]) 3301 ]) 3302
