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divert(-1)# -*- Autoconf -*- # This file is part of Autoconf. # Base M4 layer. # Requires GNU M4. # # Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, # Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2, or (at your option) # any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA # 02111-1307, USA. # # As a special exception, the Free Software Foundation gives unlimited # permission to copy, distribute and modify the configure scripts that # are the output of Autoconf. You need not follow the terms of the GNU # General Public License when using or distributing such scripts, even # though portions of the text of Autoconf appear in them. The GNU # General Public License (GPL) does govern all other use of the material # that constitutes the Autoconf program. # # Certain portions of the Autoconf source text are designed to be copied # (in certain cases, depending on the input) into the output of # Autoconf. We call these the "data" portions. The rest of the Autoconf # source text consists of comments plus executable code that decides which # of the data portions to output in any given case. We call these # comments and executable code the "non-data" portions. Autoconf never # copies any of the non-data portions into its output. # # This special exception to the GPL applies to versions of Autoconf # released by the Free Software Foundation. When you make and # distribute a modified version of Autoconf, you may extend this special # exception to the GPL to apply to your modified version as well, *unless* # your modified version has the potential to copy into its output some # of the text that was the non-data portion of the version that you started # with. (In other words, unless your change moves or copies text from # the non-data portions to the data portions.) If your modification has # such potential, you must delete any notice of this special exception # to the GPL from your modified version. # # Written by Akim Demaille. # # Set the quotes, whatever the current quoting system. changequote() changequote([, ]) # Some old m4's don't support m4exit. But they provide # equivalent functionality by core dumping because of the # long macros we define. ifdef([__gnu__], , [errprint(M4sugar requires GNU M4. Install it before installing M4sugar or set the M4 environment variable to its path name.) m4exit(2)]) ## ------------------------------- ## ## 1. Simulate --prefix-builtins. ## ## ------------------------------- ## # m4_define # m4_defn # m4_undefine define([m4_define], defn([define])) define([m4_defn], defn([defn])) define([m4_undefine], defn([undefine])) m4_undefine([define]) m4_undefine([defn]) m4_undefine([undefine]) # m4_copy(SRC, DST) # ----------------- # Define DST as the definition of SRC. # What's the difference between: # 1. m4_copy([from], [to]) # 2. m4_define([from], [to($@)]) # Well, obviously 1 is more expansive in space. Maybe 2 is more expansive # in time, but because of the space cost of 1, it's not that obvious. # Nevertheless, one huge difference is the handling of `$0'. If `from' # uses `$0', then with 1, `to''s `$0' is `to', while it is `from' in 2. # The user will certainly prefer see `from'. m4_define([m4_copy], [m4_define([$2], m4_defn([$1]))]) # m4_rename(SRC, DST) # ------------------- # Rename the macro SRC as DST. m4_define([m4_rename], [m4_copy([$1], [$2])m4_undefine([$1])]) # m4_rename_m4(MACRO-NAME) # ------------------------ # Rename MACRO-NAME as m4_MACRO-NAME. m4_define([m4_rename_m4], [m4_rename([$1], [m4_$1])]) # m4_copy_unm4(m4_MACRO-NAME) # --------------------------- # Copy m4_MACRO-NAME as MACRO-NAME. m4_define([m4_copy_unm4], [m4_copy([$1], m4_bpatsubst([$1], [^m4_$.*$], [[\1]]))]) # Some m4 internals have names colliding with tokens we might use. # Rename them a` la `m4 --prefix-builtins'. m4_rename_m4([builtin]) m4_rename_m4([changecom]) m4_rename_m4([changequote]) m4_rename_m4([debugfile]) m4_rename_m4([debugmode]) m4_rename_m4([decr]) m4_undefine([divert]) m4_rename_m4([divnum]) m4_rename_m4([dumpdef]) m4_rename_m4([errprint]) m4_rename_m4([esyscmd]) m4_rename_m4([eval]) m4_rename_m4([format]) m4_rename_m4([ifdef]) m4_rename([ifelse], [m4_if]) m4_rename_m4([include]) m4_rename_m4([incr]) m4_rename_m4([index]) m4_rename_m4([indir]) m4_rename_m4([len]) m4_rename([m4exit], [m4_exit]) m4_rename([m4wrap], [m4_wrap]) m4_rename_m4([maketemp]) m4_rename([patsubst], [m4_bpatsubst]) m4_undefine([popdef]) m4_rename_m4([pushdef]) m4_rename([regexp], [m4_bregexp]) m4_rename_m4([shift]) m4_rename_m4([sinclude]) m4_rename_m4([substr]) m4_rename_m4([symbols]) m4_rename_m4([syscmd]) m4_rename_m4([sysval]) m4_rename_m4([traceoff]) m4_rename_m4([traceon]) m4_rename_m4([translit]) m4_undefine([undivert]) ## ------------------- ## ## 2. Error messages. ## ## ------------------- ## # m4_location # ----------- m4_define([m4_location], [__file__:__line__]) # m4_errprintn(MSG) # ----------------- # Same as `errprint', but with the missing end of line. m4_define([m4_errprintn], [m4_errprint([$1 ])]) # m4_warning(MSG) # --------------- # Warn the user. m4_define([m4_warning], [m4_errprintn(m4_location[: warning: $1])]) # m4_fatal(MSG, [EXIT-STATUS]) # ---------------------------- # Fatal the user. :) m4_define([m4_fatal], [m4_errprintn(m4_location[: error: $1])dnl m4_expansion_stack_dump()dnl m4_exit(m4_if([$2],, 1, [$2]))]) # m4_assert(EXPRESSION, [EXIT-STATUS = 1]) # ---------------------------------------- # This macro ensures that EXPRESSION evaluates to true, and exits if # EXPRESSION evaluates to false. m4_define([m4_assert], [m4_if(m4_eval([$1]), 0, [m4_fatal([assert failed: $1], [$2])])]) ## ------------- ## ## 3. Warnings. ## ## ------------- ## # _m4_warn(CATEGORY, MESSAGE, STACK-TRACE) # ---------------------------------------- # Report a MESSAGE to the user if the CATEGORY of warnings is enabled. # This is for traces only. # The STACK-TRACE is a \n-separated list of "LOCATION: MESSAGE". m4_define([_m4_warn], []) # m4_warn(CATEGORY, MESSAGE) # -------------------------- # Report a MESSAGE to the user if the CATEGORY of warnings is enabled. m4_define([m4_warn], [_m4_warn([$1], [$2], m4_ifdef([m4_expansion_stack], [m4_defn([m4_expansion_stack]) m4_location[: the top level]]))dnl ]) ## ------------------- ## ## 4. File inclusion. ## ## ------------------- ## # We also want to neutralize include (and sinclude for symmetry), # but we want to extend them slightly: warn when a file is included # several times. This is in general a dangerous operation because # quite nobody quotes the first argument of m4_define. # # For instance in the following case: # m4_define(foo, [bar]) # then a second reading will turn into # m4_define(bar, [bar]) # which is certainly not what was meant. # m4_include_unique(FILE) # ----------------------- # Declare that the FILE was loading; and warn if it has already # been included. m4_define([m4_include_unique], [m4_ifdef([m4_include($1)], [m4_warn([syntax], [file `$1' included several times])])dnl m4_define([m4_include($1)])]) # m4_include(FILE) # ---------------- # As the builtin include, but warns against multiple inclusions. m4_define([m4_include], [m4_include_unique([$1])dnl m4_builtin([include], [$1])]) # m4_sinclude(FILE) # ----------------- # As the builtin sinclude, but warns against multiple inclusions. m4_define([m4_sinclude], [m4_include_unique([$1])dnl m4_builtin([sinclude], [$1])]) ## ------------------------------------ ## ## 5. Additional branching constructs. ## ## ------------------------------------ ## # Both `m4_ifval' and `m4_ifset' tests against the empty string. The # difference is that `m4_ifset' is specialized on macros. # # In case of arguments of macros, eg $[1], it makes little difference. # In the case of a macro `FOO', you don't want to check `m4_ifval(FOO, # TRUE)', because if `FOO' expands with commas, there is a shifting of # the arguments. So you want to run `m4_ifval([FOO])', but then you just # compare the *string* `FOO' against `', which, of course fails. # # So you want a variation of `m4_ifset' that expects a macro name as $[1]. # If this macro is both defined and defined to a non empty value, then # it runs TRUE etc. # m4_ifval(COND, [IF-TRUE], [IF-FALSE]) # ------------------------------------- # If COND is not the empty string, expand IF-TRUE, otherwise IF-FALSE. # Comparable to m4_ifdef. m4_define([m4_ifval], [m4_if([$1], [], [$3], [$2])]) # m4_n(TEXT) # ---------- # If TEXT is not empty, return TEXT and a new line, otherwise nothing. m4_define([m4_n], [m4_if([$1], [], [], [$1 ])]) # m4_ifvaln(COND, [IF-TRUE], [IF-FALSE]) # -------------------------------------- # Same as `m4_ifval', but add an extra newline to IF-TRUE or IF-FALSE # unless that argument is empty. m4_define([m4_ifvaln], [m4_if([$1], [], [m4_n([$3])], [m4_n([$2])])]) # m4_ifset(MACRO, [IF-TRUE], [IF-FALSE]) # -------------------------------------- # If MACRO has no definition, or of its definition is the empty string, # expand IF-FALSE, otherwise IF-TRUE. m4_define([m4_ifset], [m4_ifdef([$1], [m4_if(m4_defn([$1]), [], [$3], [$2])], [$3])]) # m4_ifndef(NAME, [IF-NOT-DEFINED], [IF-DEFINED]) # ----------------------------------------------- m4_define([m4_ifndef], [m4_ifdef([$1], [$3], [$2])]) # m4_case(SWITCH, VAL1, IF-VAL1, VAL2, IF-VAL2, ..., DEFAULT) # ----------------------------------------------------------- # m4 equivalent of # switch (SWITCH) # { # case VAL1: # IF-VAL1; # break; # case VAL2: # IF-VAL2; # break; # ... # default: # DEFAULT; # break; # }. # All the values are optional, and the macro is robust to active # symbols properly quoted. m4_define([m4_case], [m4_if([$#], 0, [], [$#], 1, [], [$#], 2, [$2], [$1], [$2], [$3], [$0([$1], m4_shiftn(3, $@))])]) # m4_bmatch(SWITCH, RE1, VAL1, RE2, VAL2, ..., DEFAULT) # ----------------------------------------------------- # m4 equivalent of # # if (SWITCH =~ RE1) # VAL1; # elif (SWITCH =~ RE2) # VAL2; # elif ... # ... # else # DEFAULT # # All the values are optional, and the macro is robust to active symbols # properly quoted. m4_define([m4_bmatch], [m4_if([$#], 0, [], [$#], 1, [], [$#], 2, [$2], [m4_if(m4_bregexp([$1], [$2]), -1, [$0([$1], m4_shiftn(3, $@))], [$3])])]) # m4_map(MACRO, LIST) # ------------------- # Invoke MACRO($1), MACRO($2) etc. where $1, $2... are the elements # of LIST (which can be lists themselves, for multiple arguments MACROs). m4_define([m4_fst], [$1]) m4_define([m4_map], [m4_if([$2], [[]], [], [$1(m4_fst($2))[]dnl m4_map([$1], m4_cdr($2))])]) # m4_map_sep(MACRO, SEPARATOR, LIST) # ---------------------------------- # Invoke MACRO($1), SEPARATOR, MACRO($2), ..., MACRO($N) where $1, $2... $N # are the elements of LIST (which can be lists themselves, for multiple # arguments MACROs). m4_define([m4_map_sep], [m4_if([$3], [[]], [], [$1(m4_fst($3))[]dnl m4_if(m4_cdr($3), [[]], [], [$2])[]dnl m4_map_sep([$1], [$2], m4_cdr($3))])]) ## ---------------------------------------- ## ## 6. Enhanced version of some primitives. ## ## ---------------------------------------- ## # m4_patsubsts(STRING, RE1, SUBST1, RE2, SUBST2, ...) # --------------------------------------------------- # m4 equivalent of # # $_ = STRING; # s/RE1/SUBST1/g; # s/RE2/SUBST2/g; # ... # # All the values are optional, and the macro is robust to active symbols # properly quoted. # # I would have liked to name this macro `m4_patsubst', unfortunately, # due to quotation problems, I need to double quote $1 below, therefore # the anchors are broken :( I can't let users be trapped by that. m4_define([m4_bpatsubsts], [m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], [$#], 2, [m4_builtin([patsubst], $@)], [$0(m4_builtin([patsubst], [[$1]], [$2], [$3]), m4_shiftn(3, $@))])]) # m4_do(STRING, ...) # ------------------ # This macro invokes all its arguments (in sequence, of course). It is # useful for making your macros more structured and readable by dropping # unnecessary dnl's and have the macros indented properly. m4_define([m4_do], [m4_if($#, 0, [], $#, 1, [$1], [$1[]m4_do(m4_shift($@))])]) # m4_define_default(MACRO, VALUE) # ------------------------------- # If MACRO is undefined, set it to VALUE. m4_define([m4_define_default], [m4_ifndef([$1], [m4_define($@)])]) # m4_default(EXP1, EXP2) # ---------------------- # Returns EXP1 if non empty, otherwise EXP2. m4_define([m4_default], [m4_ifval([$1], [$1], [$2])]) # m4_defn(NAME) # ------------- # Unlike to the original, don't tolerate popping something which is # undefined. m4_define([m4_defn], [m4_ifndef([$1], [m4_fatal([$0: undefined macro: $1])])dnl m4_builtin([defn], $@)]) # _m4_dumpdefs_up(NAME) # --------------------- m4_define([_m4_dumpdefs_up], [m4_ifdef([$1], [m4_pushdef([_m4_dumpdefs], m4_defn([$1]))dnl m4_dumpdef([$1])dnl m4_popdef([$1])dnl _m4_dumpdefs_up([$1])])]) # _m4_dumpdefs_down(NAME) # ----------------------- m4_define([_m4_dumpdefs_down], [m4_ifdef([_m4_dumpdefs], [m4_pushdef([$1], m4_defn([_m4_dumpdefs]))dnl m4_popdef([_m4_dumpdefs])dnl _m4_dumpdefs_down([$1])])]) # m4_dumpdefs(NAME) # ----------------- # Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its # value stack (most recent displayed first). m4_define([m4_dumpdefs], [_m4_dumpdefs_up([$1])dnl _m4_dumpdefs_down([$1])]) # m4_popdef(NAME) # --------------- # Unlike to the original, don't tolerate popping something which is # undefined. m4_define([m4_popdef], [m4_ifndef([$1], [m4_fatal([$0: undefined macro: $1])])dnl m4_builtin([popdef], $@)]) # m4_quote(ARGS) # -------------- # Return ARGS as a single arguments. # # It is important to realize the difference between `m4_quote(exp)' and # `[exp]': in the first case you obtain the quoted *result* of the # expansion of EXP, while in the latter you just obtain the string # `exp'. m4_define([m4_quote], [[$*]]) m4_define([m4_dquote], [[$@]]) # m4_noquote(STRING) # ------------------ # Return the result of ignoring all quotes in STRING and invoking the # macros it contains. Amongst other things useful for enabling macro # invocations inside strings with [] blocks (for instance regexps and # help-strings). m4_define([m4_noquote], [m4_changequote(-=<{,}>=-)$1-=<{}>=-m4_changequote([,])]) # m4_shiftn(N, ...) # ----------------- # Returns ... shifted N times. Useful for recursive "varargs" constructs. m4_define([m4_shiftn], [m4_assert(($1 >= 0) && ($# > $1))dnl _m4_shiftn($@)]) m4_define([_m4_shiftn], [m4_if([$1], 0, [m4_shift($@)], [_m4_shiftn(m4_eval([$1]-1), m4_shift(m4_shift($@)))])]) # m4_undefine(NAME) # ----------------- # Unlike to the original, don't tolerate undefining something which is # undefined. m4_define([m4_undefine], [m4_ifndef([$1], [m4_fatal([$0: undefined macro: $1])])dnl m4_builtin([undefine], $@)]) ## -------------------------- ## ## 7. Implementing m4 loops. ## ## -------------------------- ## # m4_for(VARIABLE, FIRST, LAST, [STEP = +/-1], EXPRESSION) # -------------------------------------------------------- # Expand EXPRESSION defining VARIABLE to FROM, FROM + 1, ..., TO. # Both limits are included, and bounds are checked for consistency. m4_define([m4_for], [m4_case(m4_sign(m4_eval($3 - $2)), 1, [m4_assert(m4_sign(m4_default($4, 1)) == 1)], -1, [m4_assert(m4_sign(m4_default($4, -1)) == -1)])dnl m4_pushdef([$1], [$2])dnl m4_if(m4_eval([$3 > $2]), 1, [_m4_for([$1], [$3], m4_default([$4], 1), [$5])], [_m4_for([$1], [$3], m4_default([$4], -1), [$5])])dnl m4_popdef([$1])]) # _m4_for(VARIABLE, FIRST, LAST, STEP, EXPRESSION) # ------------------------------------------------ # Core of the loop, no consistency checks. m4_define([_m4_for], [$4[]dnl m4_if($1, [$2], [], [m4_define([$1], m4_eval($1+[$3]))_m4_for([$1], [$2], [$3], [$4])])]) # Implementing `foreach' loops in m4 is much more tricky than it may # seem. Actually, the example of a `foreach' loop in the m4 # documentation is wrong: it does not quote the arguments properly, # which leads to undesirable expansions. # # The example in the documentation is: # # | # foreach(VAR, (LIST), STMT) # | m4_define([foreach], # | [m4_pushdef([$1])_foreach([$1], [$2], [$3])m4_popdef([$1])]) # | m4_define([_arg1], [$1]) # | m4_define([_foreach], # | [m4_if([$2], [()], , # | [m4_define([$1], _arg1$2)$3[]_foreach([$1], # | (shift$2), # | [$3])])]) # # But then if you run # # | m4_define(a, 1) # | m4_define(b, 2) # | m4_define(c, 3) # | foreach([f], [([a], [(b], [c)])], [echo f # | ]) # # it gives # # => echo 1 # => echo (2,3) # # which is not what is expected. # # Of course the problem is that many quotes are missing. So you add # plenty of quotes at random places, until you reach the expected # result. Alternatively, if you are a quoting wizard, you directly # reach the following implementation (but if you really did, then # apply to the maintenance of m4sugar!). # # | # foreach(VAR, (LIST), STMT) # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])]) # | m4_define([_arg1], [[$1]]) # | m4_define([_foreach], # | [m4_if($2, [()], , # | [m4_define([$1], [_arg1$2])$3[]_foreach([$1], # | [(shift$2)], # | [$3])])]) # # which this time answers # # => echo a # => echo (b # => echo c) # # Bingo! # # Well, not quite. # # With a better look, you realize that the parens are more a pain than # a help: since anyway you need to quote properly the list, you end up # with always using an outermost pair of parens and an outermost pair # of quotes. Rejecting the parens both eases the implementation, and # simplifies the use: # # | # foreach(VAR, (LIST), STMT) # | m4_define([foreach], [m4_pushdef([$1])_foreach($@)m4_popdef([$1])]) # | m4_define([_arg1], [$1]) # | m4_define([_foreach], # | [m4_if($2, [], , # | [m4_define([$1], [_arg1($2)])$3[]_foreach([$1], # | [shift($2)], # | [$3])])]) # # # Now, just replace the `$2' with `m4_quote($2)' in the outer `m4_if' # to improve robustness, and you come up with a quite satisfactory # implementation. # m4_foreach(VARIABLE, LIST, EXPRESSION) # -------------------------------------- # # Expand EXPRESSION assigning each value of the LIST to VARIABLE. # LIST should have the form `item_1, item_2, ..., item_n', i.e. the # whole list must *quoted*. Quote members too if you don't want them # to be expanded. # # This macro is robust to active symbols: # | m4_define(active, [ACT, IVE]) # | m4_foreach(Var, [active, active], [-Var-]) # => -ACT--IVE--ACT--IVE- # # | m4_foreach(Var, [[active], [active]], [-Var-]) # => -ACT, IVE--ACT, IVE- # # | m4_foreach(Var, [[[active]], [[active]]], [-Var-]) # => -active--active- m4_define([m4_foreach], [m4_pushdef([$1])_m4_foreach($@)m4_popdef([$1])]) # Low level macros used to define m4_foreach. m4_define([m4_car], [[$1]]) m4_define([m4_cdr], [m4_dquote(m4_shift($@))]) m4_define([_m4_foreach], [m4_if([$2], [[]], [], [m4_define([$1], m4_car($2))$3[]_m4_foreach([$1], m4_cdr($2), [$3])])]) ## --------------------------- ## ## 8. More diversion support. ## ## --------------------------- ## # _m4_divert(DIVERSION-NAME or NUMBER) # ------------------------------------ # If DIVERSION-NAME is the name of a diversion, return its number, # otherwise if is a NUMBER return it. m4_define([_m4_divert], [m4_ifdef([_m4_divert($1)], [m4_indir([_m4_divert($1)])], [$1])]) # KILL is only used to suppress output. m4_define([_m4_divert(KILL)], -1) # m4_divert(DIVERSION-NAME) # ------------------------- # Change the diversion stream to DIVERSION-NAME. m4_define([m4_divert], [m4_define([m4_divert_stack], m4_location[: $0: $1]m4_ifdef([m4_divert_stack], [ m4_defn([m4_divert_stack])]))dnl m4_builtin([divert], _m4_divert([$1]))dnl ]) # m4_divert_push(DIVERSION-NAME) # ------------------------------ # Change the diversion stream to DIVERSION-NAME, while stacking old values. m4_define([m4_divert_push], [m4_pushdef([m4_divert_stack], m4_location[: $0: $1]m4_ifdef([m4_divert_stack], [ m4_defn([m4_divert_stack])]))dnl m4_pushdef([_m4_divert_diversion], [$1])dnl m4_builtin([divert], _m4_divert(_m4_divert_diversion))dnl ]) # m4_divert_pop([DIVERSION-NAME]) # ------------------------------- # Change the diversion stream to its previous value, unstacking it. # If specified, verify we left DIVERSION-NAME. m4_define([m4_divert_pop], [m4_ifval([$1], [m4_if(_m4_divert([$1]), m4_divnum, [], [m4_fatal([$0($1): diversion mismatch: ] m4_defn([m4_divert_stack]))])])dnl m4_popdef([_m4_divert_diversion])dnl dnl m4_ifndef([_m4_divert_diversion], dnl [m4_fatal([too many m4_divert_pop])])dnl m4_builtin([divert], m4_ifdef([_m4_divert_diversion], [_m4_divert(_m4_divert_diversion)], -1))dnl m4_popdef([m4_divert_stack])dnl ]) # m4_divert_text(DIVERSION-NAME, CONTENT) # --------------------------------------- # Output CONTENT into DIVERSION-NAME (which may be a number actually). # An end of line is appended for free to CONTENT. m4_define([m4_divert_text], [m4_divert_push([$1])dnl $2 m4_divert_pop([$1])dnl ]) # m4_divert_once(DIVERSION-NAME, CONTENT) # --------------------------------------- # Output once CONTENT into DIVERSION-NAME (which may be a number # actually). An end of line is appended for free to CONTENT. m4_define([m4_divert_once], [m4_expand_once([m4_divert_text([$1], [$2])])]) # m4_undivert(DIVERSION-NAME) # --------------------------- # Undivert DIVERSION-NAME. m4_define([m4_undivert], [m4_builtin([undivert], _m4_divert([$1]))]) ## -------------------------------------------- ## ## 8. Defining macros with bells and whistles. ## ## -------------------------------------------- ## # `m4_defun' is basically `m4_define' but it equips the macro with the # needed machinery for `m4_require'. A macro must be m4_defun'd if # either it is m4_require'd, or it m4_require's. # # Two things deserve attention and are detailed below: # 1. Implementation of m4_require # 2. Keeping track of the expansion stack # # 1. Implementation of m4_require # =============================== # # Of course m4_defun AC_PROVIDE's the macro, so that a macro which has # been expanded is not expanded again when m4_require'd, but the # difficult part is the proper expansion of macros when they are # m4_require'd. # # The implementation is based on two ideas, (i) using diversions to # prepare the expansion of the macro and its dependencies (by Franc,ois # Pinard), and (ii) expand the most recently m4_require'd macros _after_ # the previous macros (by Axel Thimm). # # # The first idea: why using diversions? # ------------------------------------- # # When a macro requires another, the other macro is expanded in new # diversion, GROW. When the outer macro is fully expanded, we first # undivert the most nested diversions (GROW - 1...), and finally # undivert GROW. To understand why we need several diversions, # consider the following example: # # | m4_defun([TEST1], [Test...REQUIRE([TEST2])1]) # | m4_defun([TEST2], [Test...REQUIRE([TEST3])2]) # | m4_defun([TEST3], [Test...3]) # # Because m4_require is not required to be first in the outer macros, we # must keep the expansions of the various level of m4_require separated. # Right before executing the epilogue of TEST1, we have: # # GROW - 2: Test...3 # GROW - 1: Test...2 # GROW: Test...1 # BODY: # # Finally the epilogue of TEST1 undiverts GROW - 2, GROW - 1, and # GROW into the regular flow, BODY. # # GROW - 2: # GROW - 1: # GROW: # BODY: Test...3; Test...2; Test...1 # # (The semicolons are here for clarification, but of course are not # emitted.) This is what Autoconf 2.0 (I think) to 2.13 (I'm sure) # implement. # # # The second idea: first required first out # ----------------------------------------- # # The natural implementation of the idea above is buggy and produces # very surprising results in some situations. Let's consider the # following example to explain the bug: # # | m4_defun([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])]) # | m4_defun([TEST2a], []) # | m4_defun([TEST2b], [REQUIRE([TEST3])]) # | m4_defun([TEST3], [REQUIRE([TEST2a])]) # | # | AC_INIT # | TEST1 # # The dependencies between the macros are: # # 3 --- 2b # / \ is m4_require'd by # / \ left -------------------- right # 2a ------------ 1 # # If you strictly apply the rules given in the previous section you get: # # GROW - 2: TEST3 # GROW - 1: TEST2a; TEST2b # GROW: TEST1 # BODY: # # (TEST2a, although required by TEST3 is not expanded in GROW - 3 # because is has already been expanded before in GROW - 1, so it has # been AC_PROVIDE'd, so it is not expanded again) so when you undivert # the stack of diversions, you get: # # GROW - 2: # GROW - 1: # GROW: # BODY: TEST3; TEST2a; TEST2b; TEST1 # # i.e., TEST2a is expanded after TEST3 although the latter required the # former. # # Starting from 2.50, uses an implementation provided by Axel Thimm. # The idea is simple: the order in which macros are emitted must be the # same as the one in which macro are expanded. (The bug above can # indeed be described as: a macro has been AC_PROVIDE'd, but it is # emitted after: the lack of correlation between emission and expansion # order is guilty). # # How to do that? You keeping the stack of diversions to elaborate the # macros, but each time a macro is fully expanded, emit it immediately. # # In the example above, when TEST2a is expanded, but it's epilogue is # not run yet, you have: # # GROW - 2: # GROW - 1: TEST2a # GROW: Elaboration of TEST1 # BODY: # # The epilogue of TEST2a emits it immediately: # # GROW - 2: # GROW - 1: # GROW: Elaboration of TEST1 # BODY: TEST2a # # TEST2b then requires TEST3, so right before the epilogue of TEST3, you # have: # # GROW - 2: TEST3 # GROW - 1: Elaboration of TEST2b # GROW: Elaboration of TEST1 # BODY: TEST2a # # The epilogue of TEST3 emits it: # # GROW - 2: # GROW - 1: Elaboration of TEST2b # GROW: Elaboration of TEST1 # BODY: TEST2a; TEST3 # # TEST2b is now completely expanded, and emitted: # # GROW - 2: # GROW - 1: # GROW: Elaboration of TEST1 # BODY: TEST2a; TEST3; TEST2b # # and finally, TEST1 is finished and emitted: # # GROW - 2: # GROW - 1: # GROW: # BODY: TEST2a; TEST3; TEST2b: TEST1 # # The idea, is simple, but the implementation is a bit evolved. If you # are like me, you will want to see the actual functioning of this # implementation to be convinced. The next section gives the full # details. # # # The Axel Thimm implementation at work # ------------------------------------- # # We consider the macros above, and this configure.ac: # # AC_INIT # TEST1 # # You should keep the definitions of _m4_defun_pro, _m4_defun_epi, and # m4_require at hand to follow the steps. # # This implements tries not to assume that of the current diversion is # BODY, so as soon as a macro (m4_defun'd) is expanded, we first # record the current diversion under the name _m4_divert_dump (denoted # DUMP below for short). This introduces an important difference with # the previous versions of Autoconf: you cannot use m4_require if you # were not inside an m4_defun'd macro, and especially, you cannot # m4_require directly from the top level. # # We have not tried to simulate the old behavior (better yet, we # diagnose it), because it is too dangerous: a macro m4_require'd from # the top level is expanded before the body of `configure', i.e., before # any other test was run. I let you imagine the result of requiring # AC_STDC_HEADERS for instance, before AC_PROG_CC was actually run.... # # After AC_INIT was run, the current diversion is BODY. # * AC_INIT was run # DUMP: undefined # diversion stack: BODY |- # # * TEST1 is expanded # The prologue of TEST1 sets AC_DIVERSION_DUMP, which is the diversion # where the current elaboration will be dumped, to the current # diversion. It also m4_divert_push to GROW, where the full # expansion of TEST1 and its dependencies will be elaborated. # DUMP: BODY # BODY: empty # diversions: GROW, BODY |- # # * TEST1 requires TEST2a: prologue # m4_require m4_divert_pushes another temporary diversion GROW - 1 (in # fact, the diversion whose number is one less than the current # diversion), and expands TEST2a in there. # DUMP: BODY # BODY: empty # diversions: GROW-1, GROW, BODY |- # # * TEST2a is expanded. # Its prologue pushes the current diversion again. # DUMP: BODY # BODY: empty # diversions: GROW - 1, GROW - 1, GROW, BODY |- # It is expanded in GROW - 1, and GROW - 1 is popped by the epilogue # of TEST2a. # DUMP: BODY # BODY: nothing # GROW - 1: TEST2a # diversions: GROW - 1, GROW, BODY |- # # * TEST1 requires TEST2a: epilogue # The content of the current diversion is appended to DUMP (and removed # from the current diversion). A diversion is popped. # DUMP: BODY # BODY: TEST2a # diversions: GROW, BODY |- # # * TEST1 requires TEST2b: prologue # m4_require pushes GROW - 1 and expands TEST2b. # DUMP: BODY # BODY: TEST2a # diversions: GROW - 1, GROW, BODY |- # # * TEST2b is expanded. # Its prologue pushes the current diversion again. # DUMP: BODY # BODY: TEST2a # diversions: GROW - 1, GROW - 1, GROW, BODY |- # The body is expanded here. # # * TEST2b requires TEST3: prologue # m4_require pushes GROW - 2 and expands TEST3. # DUMP: BODY # BODY: TEST2a # diversions: GROW - 2, GROW - 1, GROW - 1, GROW, BODY |- # # * TEST3 is expanded. # Its prologue pushes the current diversion again. # DUMP: BODY # BODY: TEST2a # diversions: GROW-2, GROW-2, GROW-1, GROW-1, GROW, BODY |- # TEST3 requires TEST2a, but TEST2a has already been AC_PROVIDE'd, so # nothing happens. It's body is expanded here, and its epilogue pops a # diversion. # DUMP: BODY # BODY: TEST2a # GROW - 2: TEST3 # diversions: GROW - 2, GROW - 1, GROW - 1, GROW, BODY |- # # * TEST2b requires TEST3: epilogue # The current diversion is appended to DUMP, and a diversion is popped. # DUMP: BODY # BODY: TEST2a; TEST3 # diversions: GROW - 1, GROW - 1, GROW, BODY |- # The content of TEST2b is expanded here. # DUMP: BODY # BODY: TEST2a; TEST3 # GROW - 1: TEST2b, # diversions: GROW - 1, GROW - 1, GROW, BODY |- # The epilogue of TEST2b pops a diversion. # DUMP: BODY # BODY: TEST2a; TEST3 # GROW - 1: TEST2b, # diversions: GROW - 1, GROW, BODY |- # # * TEST1 requires TEST2b: epilogue # The current diversion is appended to DUMP, and a diversion is popped. # DUMP: BODY # BODY: TEST2a; TEST3; TEST2b # diversions: GROW, BODY |- # # * TEST1 is expanded: epilogue # TEST1's own content is in GROW, and it's epilogue pops a diversion. # DUMP: BODY # BODY: TEST2a; TEST3; TEST2b # GROW: TEST1 # diversions: BODY |- # Here, the epilogue of TEST1 notices the elaboration is done because # DUMP and the current diversion are the same, it then undiverts # GROW by hand, and undefines DUMP. # DUMP: undefined # BODY: TEST2a; TEST3; TEST2b; TEST1 # diversions: BODY |- # # # 2. Keeping track of the expansion stack # ======================================= # # When M4 expansion goes wrong it is often extremely hard to find the # path amongst macros that drove to the failure. What is needed is # the stack of macro `calls'. One could imagine that GNU M4 would # maintain a stack of macro expansions, unfortunately it doesn't, so # we do it by hand. This is of course extremely costly, but the help # this stack provides is worth it. Nevertheless to limit the # performance penalty this is implemented only for m4_defun'd macros, # not for define'd macros. # # The scheme is simplistic: each time we enter an m4_defun'd macros, # we prepend its name in m4_expansion_stack, and when we exit the # macro, we remove it (thanks to pushdef/popdef). # # In addition, we want to use the expansion stack to detect circular # m4_require dependencies. This means we need to browse the stack to # check whether a macro being expanded is m4_require'd. For ease of # implementation, and certainly for the benefit of performances, we # don't browse the m4_expansion_stack, rather each time we expand a # macro FOO we define _m4_expanding(FOO). Then m4_require(BAR) simply # needs to check whether _m4_expanding(BAR) is defined to diagnose a # circular dependency. # # To improve the diagnostic, in addition to keeping track of the stack # of macro calls, m4_expansion_stack also records the m4_require # stack. Note that therefore an m4_defun'd macro being required will # appear twice in the stack: the first time because it is required, # the second because it is expanded. We can avoid this, but it has # two small drawbacks: (i) the implementation is slightly more # complex, and (ii) it hides the difference between define'd macros # (which don't appear in m4_expansion_stack) and m4_defun'd macros # (which do). The more debugging information, the better. # m4_expansion_stack_push(TEXT) # ----------------------------- m4_define([m4_expansion_stack_push], [m4_pushdef([m4_expansion_stack], [$1]m4_ifdef([m4_expansion_stack], [ m4_defn([m4_expansion_stack])]))]) # m4_expansion_stack_pop # ---------------------- # Dump the expansion stack. m4_define([m4_expansion_stack_pop], [m4_popdef([m4_expansion_stack])]) # m4_expansion_stack_dump # ----------------------- # Dump the expansion stack. m4_define([m4_expansion_stack_dump], [m4_ifdef([m4_expansion_stack], [m4_errprintn(m4_defn([m4_expansion_stack]))])dnl m4_errprintn(m4_location[: the top level])]) # _m4_divert(GROW) # ---------------- # This diversion is used by the m4_defun/m4_require machinery. It is # important to keep room before GROW because for each nested # AC_REQUIRE we use an additional diversion (i.e., two m4_require's # will use GROW - 2. More than 3 levels has never seemed to be # needed.) # # ... # - GROW - 2 # m4_require'd code, 2 level deep # - GROW - 1 # m4_require'd code, 1 level deep # - GROW # m4_defun'd macros are elaborated here. m4_define([_m4_divert(GROW)], 10000) # _m4_defun_pro(MACRO-NAME) # ------------------------- # The prologue for Autoconf macros. m4_define([_m4_defun_pro], [m4_expansion_stack_push(m4_defn([m4_location($1)])[: $1 is expanded from...])dnl m4_pushdef([_m4_expanding($1)])dnl m4_ifdef([_m4_divert_dump], [m4_divert_push(m4_defn([_m4_divert_diversion]))], [m4_copy([_m4_divert_diversion], [_m4_divert_dump])dnl m4_divert_push([GROW])])dnl ]) # _m4_defun_epi(MACRO-NAME) # ------------------------- # The Epilogue for Autoconf macros. MACRO-NAME only helps tracing # the PRO/EPI pairs. m4_define([_m4_defun_epi], [m4_divert_pop()dnl m4_if(_m4_divert_dump, _m4_divert_diversion, [m4_undivert([GROW])dnl m4_undefine([_m4_divert_dump])])dnl m4_expansion_stack_pop()dnl m4_popdef([_m4_expanding($1)])dnl m4_provide([$1])dnl ]) # m4_defun(NAME, EXPANSION) # ------------------------- # Define a macro which automatically provides itself. Add machinery # so the macro automatically switches expansion to the diversion # stack if it is not already using it. In this case, once finished, # it will bring back all the code accumulated in the diversion stack. # This, combined with m4_require, achieves the topological ordering of # macros. We don't use this macro to define some frequently called # macros that are not involved in ordering constraints, to save m4 # processing. m4_define([m4_defun], [m4_define([m4_location($1)], m4_location)dnl m4_define([$1], [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])]) # m4_defun_once(NAME, EXPANSION) # ------------------------------ # As m4_defun, but issues the EXPANSION only once, and warns if used # several times. m4_define([m4_defun_once], [m4_define([m4_location($1)], m4_location)dnl m4_define([$1], [m4_provide_if([$1], [m4_warn([syntax], [$1 invoked multiple times])], [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])])]) # m4_pattern_forbid(ERE, [WHY]) # ----------------------------- # Declare that no token matching the extended regular expression ERE # should be seen in the output but if... m4_define([m4_pattern_forbid], []) # m4_pattern_allow(ERE) # --------------------- # ... but if that token matches the extended regular expression ERE. # Both used via traces. m4_define([m4_pattern_allow], []) ## ----------------------------- ## ## Dependencies between macros. ## ## ----------------------------- ## # m4_before(THIS-MACRO-NAME, CALLED-MACRO-NAME) # --------------------------------------------- m4_define([m4_before], [m4_provide_if([$2], [m4_warn([syntax], [$2 was called before $1])])]) # m4_require(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK]) # ----------------------------------------------------------- # If NAME-TO-CHECK has never been expanded (actually, if it is not # m4_provide'd), expand BODY-TO-EXPAND *before* the current macro # expansion. Once expanded, emit it in _m4_divert_dump. Keep track # of the m4_require chain in m4_expansion_stack. # # The normal cases are: # # - NAME-TO-CHECK == BODY-TO-EXPAND # Which you can use for regular macros with or without arguments, e.g., # m4_require([AC_PROG_CC], [AC_PROG_CC]) # m4_require([AC_CHECK_HEADERS(limits.h)], [AC_CHECK_HEADERS(limits.h)]) # which is just the same as # m4_require([AC_PROG_CC]) # m4_require([AC_CHECK_HEADERS(limits.h)]) # # - BODY-TO-EXPAND == m4_indir([NAME-TO-CHECK]) # In the case of macros with irregular names. For instance: # m4_require([AC_LANG_COMPILER(C)], [indir([AC_LANG_COMPILER(C)])]) # which means `if the macro named `AC_LANG_COMPILER(C)' (the parens are # part of the name, it is not an argument) has not been run, then # call it.' # Had you used # m4_require([AC_LANG_COMPILER(C)], [AC_LANG_COMPILER(C)]) # then m4_require would have tried to expand `AC_LANG_COMPILER(C)', i.e., # call the macro `AC_LANG_COMPILER' with `C' as argument. # # You could argue that `AC_LANG_COMPILER', when it receives an argument # such as `C' should dispatch the call to `AC_LANG_COMPILER(C)'. But this # `extension' prevents `AC_LANG_COMPILER' from having actual arguments that # it passes to `AC_LANG_COMPILER(C)'. m4_define([m4_require], [m4_expansion_stack_push(m4_location[: $1 is required by...])dnl m4_ifdef([_m4_expanding($1)], [m4_fatal([$0: circular dependency of $1])])dnl m4_ifndef([_m4_divert_dump], [m4_fatal([$0: cannot be used outside of an m4_defun'd macro])])dnl m4_provide_if([$1], [], [m4_divert_push(m4_eval(m4_divnum - 1))dnl m4_default([$2], [$1]) m4_divert(m4_defn([_m4_divert_dump]))dnl m4_undivert(m4_defn([_m4_divert_diversion]))dnl m4_divert_pop(m4_defn([_m4_divert_dump]))])dnl m4_provide_if([$1], [], [m4_warn([syntax], [$1 is m4_require'd but is not m4_defun'd])])dnl m4_expansion_stack_pop()dnl ]) # m4_expand_once(TEXT, [WITNESS = TEXT]) # -------------------------------------- # If TEXT has never been expanded, expand it *here*. Use WITNESS as # as a memory that TEXT has already been expanded. m4_define([m4_expand_once], [m4_provide_if(m4_ifval([$2], [[$2]], [[$1]]), [], [m4_provide(m4_ifval([$2], [[$2]], [[$1]]))[]$1])]) # m4_provide(MACRO-NAME) # ---------------------- m4_define([m4_provide], [m4_define([m4_provide($1)])]) # m4_provide_if(MACRO-NAME, IF-PROVIDED, IF-NOT-PROVIDED) # ------------------------------------------------------- # If MACRO-NAME is provided do IF-PROVIDED, else IF-NOT-PROVIDED. # The purpose of this macro is to provide the user with a means to # check macros which are provided without letting her know how the # information is coded. m4_define([m4_provide_if], [m4_ifdef([m4_provide($1)], [$2], [$3])]) ## -------------------- ## ## 9. Text processing. ## ## -------------------- ## # m4_cr_letters # m4_cr_LETTERS # m4_cr_Letters # ------------- m4_define([m4_cr_letters], [abcdefghijklmnopqrstuvwxyz]) m4_define([m4_cr_LETTERS], [ABCDEFGHIJKLMNOPQRSTUVWXYZ]) m4_define([m4_cr_Letters], m4_defn([m4_cr_letters])dnl m4_defn([m4_cr_LETTERS])dnl ) # m4_cr_digits # ------------ m4_define([m4_cr_digits], [0123456789]) # m4_cr_symbols1 & m4_cr_symbols2 # ------------------------------- m4_define([m4_cr_symbols1], m4_defn([m4_cr_Letters])dnl _) m4_define([m4_cr_symbols2], m4_defn([m4_cr_symbols1])dnl m4_defn([m4_cr_digits])dnl ) # m4_re_escape(STRING) # -------------------- # Escape BRE active characters in STRING. m4_define([m4_re_escape], [m4_bpatsubst([$1], [[][+*.]], [\\\&])]) # m4_re_string # ------------ # Regexp for `[a-zA-Z_0-9]*' m4_define([m4_re_string], m4_defn([m4_cr_symbols2])dnl [*]dnl ) # m4_re_word # ---------- # Regexp for `[a-zA-Z_][a-zA-Z_0-9]*' m4_define([m4_re_word], m4_defn([m4_cr_symbols1])dnl m4_defn([m4_re_string])dnl ) # m4_tolower(STRING) # m4_toupper(STRING) # ------------------ # These macros lowercase and uppercase strings. m4_define([m4_tolower], [m4_translit([$1], m4_defn([m4_cr_LETTERS]), m4_defn([m4_cr_letters]))]) m4_define([m4_toupper], [m4_translit([$1], m4_defn([m4_cr_letters]), m4_defn([m4_cr_LETTERS]))]) # m4_split(STRING, [REGEXP]) # -------------------------- # # Split STRING into an m4 list of quoted elements. The elements are # quoted with [ and ]. Beginning spaces and end spaces *are kept*. # Use m4_strip to remove them. # # REGEXP specifies where to split. Default is [\t ]+. # # Pay attention to the m4_changequotes. Inner m4_changequotes exist for # obvious reasons (we want to insert square brackets). Outer # m4_changequotes are needed because otherwise the m4 parser, when it # sees the closing bracket we add to the result, believes it is the # end of the body of the macro we define. # # Also, notice that $1 is quoted twice, since we want the result to # be quoted. Then you should understand that the argument of # patsubst is ``STRING'' (i.e., with additional `` and ''). # # This macro is safe on active symbols, i.e.: # m4_define(active, ACTIVE) # m4_split([active active ])end # => [active], [active], []end m4_changequote(<<, >>) m4_define(<<m4_split>>, <<m4_changequote(``, '')dnl [dnl Can't use m4_default here instead of m4_if, because m4_default uses dnl [ and ] as quotes. m4_bpatsubst(````$1'''', m4_if(``$2'',, ``[ ]+'', ``$2''), ``], ['')]dnl m4_changequote([, ])>>) m4_changequote([, ]) # m4_flatten(STRING) # ------------------ # If STRING contains end of lines, replace them with spaces. If there # are backslashed end of lines, remove them. This macro is safe with # active symbols. # m4_define(active, ACTIVE) # m4_flatten([active # act\ # ive])end # => active activeend m4_define([m4_flatten], [m4_translit(m4_bpatsubst([[[$1]]], [\\ ]), [ ], [ ])]) # m4_strip(STRING) # ---------------- # Expands into STRING with tabs and spaces singled out into a single # space, and removing leading and trailing spaces. # # This macro is robust to active symbols. # m4_define(active, ACTIVE) # m4_strip([ active active ])end # => active activeend # # This macro is fun! Because we want to preserve active symbols, STRING # must be quoted for each evaluation, which explains there are 4 levels # of brackets around $1 (don't forget that the result must be quoted # too, hence one more quoting than applications). # # Then notice the 2 last patterns: they are in charge of removing the # leading/trailing spaces. Why not just `[^ ]'? Because they are # applied to doubly quoted strings, i.e. more or less [[STRING]]. So # if there is a leading space in STRING, then it is the *third* # character, since there are two leading `['; equally for the last pattern. m4_define([m4_strip], [m4_bpatsubsts([[$1]], [[ ]+], [ ], [^$..$ ], [\1], [ $..$$], [\1])]) # m4_normalize(STRING) # -------------------- # Apply m4_flatten and m4_strip to STRING. # # The argument is quoted, so that the macro is robust to active symbols: # # m4_define(active, ACTIVE) # m4_normalize([ act\ # ive # active ])end # => active activeend m4_define([m4_normalize], [m4_strip(m4_flatten([$1]))]) # m4_join(SEP, ARG1, ARG2...) # --------------------------- # Produce ARG1SEPARG2...SEPARGn. m4_defun([m4_join], [m4_case([$#], [1], [], [2], [[$2]], [[$2][$1]$0([$1], m4_shiftn(2, $@))])]) # m4_append(MACRO-NAME, STRING, [SEPARATOR]) # ------------------------------------------ # Redefine MACRO-NAME to hold its former content plus `SEPARATOR`'STRING' # at the end. It is valid to use this macro with MACRO-NAME undefined, # in which case no SEPARATOR is added. Be aware that the criterion is # `not being defined', and not `not being empty'. # # This macro is robust to active symbols. It can be used to grow # strings. # # | m4_define(active, ACTIVE) # | m4_append([sentence], [This is an]) # | m4_append([sentence], [ active ]) # | m4_append([sentence], [symbol.]) # | sentence # | m4_undefine([active])dnl # | sentence # => This is an ACTIVE symbol. # => This is an active symbol. # # It can be used to define hooks. # # | m4_define(active, ACTIVE) # | m4_append([hooks], [m4_define([act1], [act2])]) # | m4_append([hooks], [m4_define([act2], [active])]) # | m4_undefine([active]) # | act1 # | hooks # | act1 # => act1 # => # => active m4_define([m4_append], [m4_define([$1], m4_ifdef([$1], [m4_defn([$1])$3])[$2])]) # m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR]) # ----------------------------------------------- # As `m4_append', but append only if not yet present. m4_define([m4_append_uniq], [m4_ifdef([$1], [m4_bmatch([$3]m4_defn([$1])[$3], m4_re_escape([$3$2$3]), [], [m4_append($@)])], [m4_append($@)])]) # m4_text_wrap(STRING, [PREFIX], [FIRST-PREFIX], [WIDTH]) # ------------------------------------------------------- # Expands into STRING wrapped to hold in WIDTH columns (default = 79). # If prefix is set, each line is prefixed with it. If FIRST-PREFIX is # specified, then the first line is prefixed with it. As a special # case, if the length of the first prefix is greater than that of # PREFIX, then FIRST-PREFIX will be left alone on the first line. # # Typical outputs are: # # m4_text_wrap([Short string */], [ ], [/* ], 20) # => /* Short string */ # # m4_text_wrap([Much longer string */], [ ], [/* ], 20) # => /* Much longer # => string */ # # m4_text_wrap([Short doc.], [ ], [ --short ], 30) # => --short Short doc. # # m4_text_wrap([Short doc.], [ ], [ --too-wide ], 30) # => --too-wide # => Short doc. # # m4_text_wrap([Super long documentation.], [ ], [ --too-wide ], 30) # => --too-wide # => Super long # => documentation. # # FIXME: there is no checking of a longer PREFIX than WIDTH, but do # we really want to bother with people trying each single corner # of a software? # # This macro does not leave a trailing space behind the last word, # what complicates it a bit. The algorithm is stupid simple: all the # words are preceded by m4_Separator which is defined to empty for the # first word, and then ` ' (single space) for all the others. m4_define([m4_text_wrap], [m4_pushdef([m4_Prefix], m4_default([$2], []))dnl m4_pushdef([m4_Prefix1], m4_default([$3], [m4_Prefix]))dnl m4_pushdef([m4_Width], m4_default([$4], 79))dnl m4_pushdef([m4_Cursor], m4_len(m4_Prefix1))dnl m4_pushdef([m4_Separator], [])dnl m4_Prefix1[]dnl m4_if(m4_eval(m4_Cursor > m4_len(m4_Prefix)), 1, [m4_define([m4_Cursor], m4_len(m4_Prefix)) m4_Prefix])[]dnl m4_foreach([m4_Word], m4_quote(m4_split(m4_normalize([$1]))), [m4_define([m4_Cursor], m4_eval(m4_Cursor + m4_len(m4_defn([m4_Word])) + 1))dnl dnl New line if too long, else insert a space unless it is the first dnl of the words. m4_if(m4_eval(m4_Cursor > m4_Width), 1, [m4_define([m4_Cursor], m4_eval(m4_len(m4_Prefix) + m4_len(m4_defn([m4_Word])) + 1))] m4_Prefix, [m4_Separator])[]dnl m4_defn([m4_Word])[]dnl m4_define([m4_Separator], [ ])])dnl m4_popdef([m4_Separator])dnl m4_popdef([m4_Cursor])dnl m4_popdef([m4_Width])dnl m4_popdef([m4_Prefix1])dnl m4_popdef([m4_Prefix])dnl ]) # m4_text_box(MESSAGE, [FRAME-CHARACTER = `-']) # --------------------------------------------- m4_define([m4_text_box], [@%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@ @%:@@%:@ $1 @%:@@%:@ @%:@@%:@ m4_bpatsubst([$1], [.], m4_if([$2], [], [[-]], [[$2]])) @%:@@%:@[]dnl ]) ## ----------------------- ## ## 10. Number processing. ## ## ----------------------- ## # m4_sign(A) # ---------- # # The sign of the integer A. m4_define([m4_sign], [m4_bmatch([$1], [^-], -1, [^0+], 0, 1)]) # m4_cmp(A, B) # ------------ # # Compare two integers. # A < B -> -1 # A = B -> 0 # A > B -> 1 m4_define([m4_cmp], [m4_sign(m4_eval([$1 - $2]))]) # m4_list_cmp(A, B) # ----------------- # # Compare the two lists of integers A and B. For instance: # m4_list_cmp((1, 0), (1)) -> 0 # m4_list_cmp((1, 0), (1, 0)) -> 0 # m4_list_cmp((1, 2), (1, 0)) -> 1 # m4_list_cmp((1, 2, 3), (1, 2)) -> 1 # m4_list_cmp((1, 2, -3), (1, 2)) -> -1 # m4_list_cmp((1, 0), (1, 2)) -> -1 # m4_list_cmp((1), (1, 2)) -> -1 m4_define([m4_list_cmp], [m4_if([$1$2], [()()], 0, [$1], [()], [$0((0), [$2])], [$2], [()], [$0([$1], (0))], [m4_case(m4_cmp(m4_car$1, m4_car$2), -1, -1, 1, 1, 0, [$0((m4_shift$1), (m4_shift$2))])])]) ## ------------------------ ## ## 11. Version processing. ## ## ------------------------ ## # m4_version_unletter(VERSION) # ---------------------------- # Normalize beta version numbers with letters to numbers only for comparison. # # Nl -> (N+1).-1.(l#) # #i.e., 2.14a -> 2.15.-1.1, 2.14b -> 2.15.-1.2, etc. # This macro is absolutely not robust to active macro, it expects # reasonable version numbers and is valid up to `z', no double letters. m4_define([m4_version_unletter], [m4_translit(m4_bpatsubsts([$1], [$[0-9]+$$[abcdefghi]$], [m4_eval(\1 + 1).-1.\2], [$[0-9]+$$[jklmnopqrs]$], [m4_eval(\1 + 1).-1.1\2], [$[0-9]+$$[tuvwxyz]$], [m4_eval(\1 + 1).-1.2\2]), [abcdefghijklmnopqrstuvwxyz], [12345678901234567890123456])]) # m4_version_compare(VERSION-1, VERSION-2) # ---------------------------------------- # Compare the two version numbers and expand into # -1 if VERSION-1 < VERSION-2 # 0 if = # 1 if > m4_define([m4_version_compare], [m4_list_cmp((m4_split(m4_version_unletter([$1]), [\.])), (m4_split(m4_version_unletter([$2]), [\.])))]) # m4_PACKAGE_NAME # m4_PACKAGE_TARNAME # m4_PACKAGE_VERSION # m4_PACKAGE_STRING # m4_PACKAGE_BUGREPORT # -------------------- m4_include([m4sugar/version.m4]) # m4_version_prereq(VERSION, [IF-OK], [IF-NOT = FAIL]) # ---------------------------------------------------- # Check this Autoconf version against VERSION. m4_define([m4_version_prereq], [m4_if(m4_version_compare(m4_defn([m4_PACKAGE_VERSION]), [$1]), -1, [m4_default([$3], [m4_fatal([Autoconf version $1 or higher is required], 63)])], [$2])[]dnl ]) ## ------------------- ## ## 12. File handling. ## ## ------------------- ## # It is a real pity that M4 comes with no macros to bind a diversion # to a file. So we have to deal without, which makes us a lot more # fragile that we should. # m4_file_append(FILE-NAME, CONTENT) # ---------------------------------- m4_define([m4_file_append], [m4_syscmd([cat >>$1 <<_m4eof $2 _m4eof ]) m4_if(m4_sysval, [0], [], [m4_fatal([$0: cannot write: $1])])]) ## ------------------------ ## ## 13. Setting M4sugar up. ## ## ------------------------ ## # m4_init # ------- m4_define([m4_init], [# All the M4sugar macros start with `m4_', except `dnl' kept as is # for sake of simplicity. m4_pattern_forbid([^_?m4_]) m4_pattern_forbid([^dnl$]) # Check the divert push/pop perfect balance. m4_wrap([m4_ifdef([_m4_divert_diversion], [m4_fatal([$0: unbalanced m4_divert_push:] m4_defn([m4_divert_stack]))])[]]) m4_divert_push([KILL]) m4_wrap([m4_divert_pop([KILL])[]]) ])