diff options
Diffstat (limited to 'gnuwin32/bin/data/m4sugar')
| -rw-r--r-- | gnuwin32/bin/data/m4sugar/foreach.m4 | 362 | ||||
| -rw-r--r-- | gnuwin32/bin/data/m4sugar/m4sugar.m4 | 3307 |
2 files changed, 3669 insertions, 0 deletions
diff --git a/gnuwin32/bin/data/m4sugar/foreach.m4 b/gnuwin32/bin/data/m4sugar/foreach.m4 new file mode 100644 index 00000000..f6a63944 --- /dev/null +++ b/gnuwin32/bin/data/m4sugar/foreach.m4 @@ -0,0 +1,362 @@ +# -*- Autoconf -*- +# This file is part of Autoconf. +# foreach-based replacements for recursive functions. +# Speeds up GNU M4 1.4.x by avoiding quadratic $@ recursion, but penalizes +# GNU M4 1.6 by requiring more memory and macro expansions. +# +# Copyright (C) 2008-2013 Free Software Foundation, Inc. + +# This file is part of Autoconf. 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 3 of the License, 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. +# +# Under Section 7 of GPL version 3, you are granted additional +# permissions described in the Autoconf Configure Script Exception, +# version 3.0, as published by the Free Software Foundation. +# +# You should have received a copy of the GNU General Public License +# and a copy of the Autoconf Configure Script Exception along with +# this program; see the files COPYINGv3 and COPYING.EXCEPTION +# respectively. If not, see <http://www.gnu.org/licenses/>. + +# Written by Eric Blake. + +# In M4 1.4.x, every byte of $@ is rescanned. This means that an +# algorithm on n arguments that recurses with one less argument each +# iteration will scan n * (n + 1) / 2 arguments, for O(n^2) time. In +# M4 1.6, this was fixed so that $@ is only scanned once, then +# back-references are made to information stored about the scan. +# Thus, n iterations need only scan n arguments, for O(n) time. +# Additionally, in M4 1.4.x, recursive algorithms did not clean up +# memory very well, requiring O(n^2) memory rather than O(n) for n +# iterations. +# +# This file is designed to overcome the quadratic nature of $@ +# recursion by writing a variant of m4_foreach that uses m4_for rather +# than $@ recursion to operate on the list. This involves more macro +# expansions, but avoids the need to rescan a quadratic number of +# arguments, making these replacements very attractive for M4 1.4.x. +# On the other hand, in any version of M4, expanding additional macros +# costs additional time; therefore, in M4 1.6, where $@ recursion uses +# fewer macros, these replacements actually pessimize performance. +# Additionally, the use of $10 to mean the tenth argument violates +# POSIX; although all versions of m4 1.4.x support this meaning, a +# future m4 version may switch to take it as the first argument +# concatenated with a literal 0, so the implementations in this file +# are not future-proof. Thus, this file is conditionally included as +# part of m4_init(), only when it is detected that M4 probably has +# quadratic behavior (ie. it lacks the macro __m4_version__). +# +# Please keep this file in sync with m4sugar.m4. + +# _m4_foreach(PRE, POST, IGNORED, ARG...) +# --------------------------------------- +# Form the common basis of the m4_foreach and m4_map macros. For each +# ARG, expand PRE[ARG]POST[]. The IGNORED argument makes recursion +# easier, and must be supplied rather than implicit. +# +# This version minimizes the number of times that $@ is evaluated by +# using m4_for to generate a boilerplate into _m4_f then passing $@ to +# that temporary macro. Thus, the recursion is done in m4_for without +# reparsing any user input, and is not quadratic. For an idea of how +# this works, note that m4_foreach(i,[1,2],[i]) calls +# _m4_foreach([m4_define([i],],[)i],[],[1],[2]) +# which defines _m4_f: +# $1[$4]$2[]$1[$5]$2[]_m4_popdef([_m4_f]) +# then calls _m4_f([m4_define([i],],[)i],[],[1],[2]) for a net result: +# m4_define([i],[1])i[]m4_define([i],[2])i[]_m4_popdef([_m4_f]). +m4_define([_m4_foreach], +[m4_if([$#], [3], [], + [m4_pushdef([_m4_f], _m4_for([4], [$#], [1], + [$0_([1], [2],], [)])[_m4_popdef([_m4_f])])_m4_f($@)])]) + +m4_define([_m4_foreach_], +[[$$1[$$3]$$2[]]]) + +# m4_case(SWITCH, VAL1, IF-VAL1, VAL2, IF-VAL2, ..., DEFAULT) +# ----------------------------------------------------------- +# Find the first VAL that SWITCH matches, and expand the corresponding +# IF-VAL. If there are no matches, expand DEFAULT. +# +# Use m4_for to create a temporary macro in terms of a boilerplate +# m4_if with final cleanup. If $# is even, we have DEFAULT; if it is +# odd, then rounding the last $# up in the temporary macro is +# harmless. For example, both m4_case(1,2,3,4,5) and +# m4_case(1,2,3,4,5,6) result in the intermediate _m4_case being +# m4_if([$1],[$2],[$3],[$1],[$4],[$5],_m4_popdef([_m4_case])[$6]) +m4_define([m4_case], +[m4_if(m4_eval([$# <= 2]), [1], [$2], +[m4_pushdef([_$0], [m4_if(]_m4_for([2], m4_eval([($# - 1) / 2 * 2]), [2], + [_$0_(], [)])[_m4_popdef( + [_$0])]m4_dquote($m4_eval([($# + 1) & ~1]))[)])_$0($@)])]) + +m4_define([_m4_case_], +[$0_([1], [$1], m4_incr([$1]))]) + +m4_define([_m4_case__], +[[[$$1],[$$2],[$$3],]]) + +# m4_bmatch(SWITCH, RE1, VAL1, RE2, VAL2, ..., DEFAULT) +# ----------------------------------------------------- +# m4 equivalent of +# +# if (SWITCH =~ RE1) +# VAL1; +# elif (SWITCH =~ RE2) +# VAL2; +# elif ... +# ... +# else +# DEFAULT +# +# We build the temporary macro _m4_b: +# m4_define([_m4_b], _m4_defn([_m4_bmatch]))_m4_b([$1], [$2], [$3])... +# _m4_b([$1], [$m-1], [$m])_m4_b([], [], [$m+1]_m4_popdef([_m4_b])) +# then invoke m4_unquote(_m4_b($@)), for concatenation with later text. +m4_define([m4_bmatch], +[m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], + [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], + [$#], 2, [$2], + [m4_pushdef([_m4_b], [m4_define([_m4_b], + _m4_defn([_$0]))]_m4_for([3], m4_eval([($# + 1) / 2 * 2 - 1]), + [2], [_$0_(], [)])[_m4_b([], [],]m4_dquote([$]m4_eval( + [($# + 1) / 2 * 2]))[_m4_popdef([_m4_b]))])m4_unquote(_m4_b($@))])]) + +m4_define([_m4_bmatch], +[m4_if(m4_bregexp([$1], [$2]), [-1], [], [[$3]m4_define([$0])])]) + +m4_define([_m4_bmatch_], +[$0_([1], m4_decr([$1]), [$1])]) + +m4_define([_m4_bmatch__], +[[_m4_b([$$1], [$$2], [$$3])]]) + + +# m4_cond(TEST1, VAL1, IF-VAL1, TEST2, VAL2, IF-VAL2, ..., [DEFAULT]) +# ------------------------------------------------------------------- +# Similar to m4_if, except that each TEST is expanded when encountered. +# If the expansion of TESTn matches the string VALn, the result is IF-VALn. +# The result is DEFAULT if no tests passed. This macro allows +# short-circuiting of expensive tests, where it pays to arrange quick +# filter tests to run first. +# +# m4_cond already guarantees either 3*n or 3*n + 1 arguments, 1 <= n. +# We only have to speed up _m4_cond, by building the temporary _m4_c: +# m4_define([_m4_c], _m4_defn([m4_unquote]))_m4_c([m4_if(($1), [($2)], +# [[$3]m4_define([_m4_c])])])_m4_c([m4_if(($4), [($5)], +# [[$6]m4_define([_m4_c])])])..._m4_c([m4_if(($m-2), [($m-1)], +# [[$m]m4_define([_m4_c])])])_m4_c([[$m+1]]_m4_popdef([_m4_c])) +# We invoke m4_unquote(_m4_c($@)), for concatenation with later text. +m4_define([_m4_cond], +[m4_pushdef([_m4_c], [m4_define([_m4_c], + _m4_defn([m4_unquote]))]_m4_for([2], m4_eval([$# / 3 * 3 - 1]), [3], + [$0_(], [)])[_m4_c(]m4_dquote(m4_dquote( + [$]m4_eval([$# / 3 * 3 + 1])))[_m4_popdef([_m4_c]))])m4_unquote(_m4_c($@))]) + +m4_define([_m4_cond_], +[$0_(m4_decr([$1]), [$1], m4_incr([$1]))]) + +m4_define([_m4_cond__], +[[_m4_c([m4_if(($$1), [($$2)], [[$$3]m4_define([_m4_c])])])]]) + +# m4_bpatsubsts(STRING, RE1, SUBST1, RE2, SUBST2, ...) +# ---------------------------------------------------- +# m4 equivalent of +# +# $_ = STRING; +# s/RE1/SUBST1/g; +# s/RE2/SUBST2/g; +# ... +# +# m4_bpatsubsts already validated an odd number of arguments; we only +# need to speed up _m4_bpatsubsts. To avoid nesting, we build the +# temporary _m4_p: +# m4_define([_m4_p], [$1])m4_define([_m4_p], +# m4_bpatsubst(m4_dquote(_m4_defn([_m4_p])), [$2], [$3]))m4_define([_m4_p], +# m4_bpatsubst(m4_dquote(_m4_defn([_m4_p])), [$4], [$5]))m4_define([_m4_p],... +# m4_bpatsubst(m4_dquote(_m4_defn([_m4_p])), [$m-1], [$m]))m4_unquote( +# _m4_defn([_m4_p])_m4_popdef([_m4_p])) +m4_define([_m4_bpatsubsts], +[m4_pushdef([_m4_p], [m4_define([_m4_p], + ]m4_dquote([$]1)[)]_m4_for([3], [$#], [2], [$0_(], + [)])[m4_unquote(_m4_defn([_m4_p])_m4_popdef([_m4_p]))])_m4_p($@)]) + +m4_define([_m4_bpatsubsts_], +[$0_(m4_decr([$1]), [$1])]) + +m4_define([_m4_bpatsubsts__], +[[m4_define([_m4_p], +m4_bpatsubst(m4_dquote(_m4_defn([_m4_p])), [$$1], [$$2]))]]) + +# m4_shiftn(N, ...) +# ----------------- +# Returns ... shifted N times. Useful for recursive "varargs" constructs. +# +# m4_shiftn already validated arguments; we only need to speed up +# _m4_shiftn. If N is 3, then we build the temporary _m4_s, defined as +# ,[$5],[$6],...,[$m]_m4_popdef([_m4_s]) +# before calling m4_shift(_m4_s($@)). +m4_define([_m4_shiftn], +[m4_if(m4_incr([$1]), [$#], [], [m4_pushdef([_m4_s], + _m4_for(m4_eval([$1 + 2]), [$#], [1], + [[,]m4_dquote($], [)])[_m4_popdef([_m4_s])])m4_shift(_m4_s($@))])]) + +# 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. +# +# Here, we use the temporary macro _m4_do, defined as +# $1[]$2[]...[]$n[]_m4_popdef([_m4_do]) +m4_define([m4_do], +[m4_if([$#], [0], [], + [m4_pushdef([_$0], _m4_for([1], [$#], [1], + [$], [[[]]])[_m4_popdef([_$0])])_$0($@)])]) + +# m4_dquote_elt(ARGS) +# ------------------- +# Return ARGS as an unquoted list of double-quoted arguments. +# +# _m4_foreach to the rescue. +m4_define([m4_dquote_elt], +[m4_if([$#], [0], [], [[[$1]]_m4_foreach([,m4_dquote(], [)], $@)])]) + +# m4_reverse(ARGS) +# ---------------- +# Output ARGS in reverse order. +# +# Invoke _m4_r($@) with the temporary _m4_r built as +# [$m], [$m-1], ..., [$2], [$1]_m4_popdef([_m4_r]) +m4_define([m4_reverse], +[m4_if([$#], [0], [], [$#], [1], [[$1]], +[m4_pushdef([_m4_r], [[$$#]]_m4_for(m4_decr([$#]), [1], [-1], + [[, ]m4_dquote($], [)])[_m4_popdef([_m4_r])])_m4_r($@)])]) + + +# m4_map_args_pair(EXPRESSION, [END-EXPR = EXPRESSION], ARG...) +# ------------------------------------------------------------- +# Perform a pairwise grouping of consecutive ARGs, by expanding +# EXPRESSION([ARG1], [ARG2]). If there are an odd number of ARGs, the +# final argument is expanded with END-EXPR([ARGn]). +# +# Build the temporary macro _m4_map_args_pair, with the $2([$m+1]) +# only output if $# is odd: +# $1([$3], [$4])[]$1([$5], [$6])[]...$1([$m-1], +# [$m])[]m4_default([$2], [$1])([$m+1])[]_m4_popdef([_m4_map_args_pair]) +m4_define([m4_map_args_pair], +[m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], + [$#], [1], [m4_fatal([$0: too few arguments: $#: $1])], + [$#], [2], [], + [$#], [3], [m4_default([$2], [$1])([$3])[]], + [m4_pushdef([_$0], _m4_for([3], + m4_eval([$# / 2 * 2 - 1]), [2], [_$0_(], [)])_$0_end( + [1], [2], [$#])[_m4_popdef([_$0])])_$0($@)])]) + +m4_define([_m4_map_args_pair_], +[$0_([1], [$1], m4_incr([$1]))]) + +m4_define([_m4_map_args_pair__], +[[$$1([$$2], [$$3])[]]]) + +m4_define([_m4_map_args_pair_end], +[m4_if(m4_eval([$3 & 1]), [1], [[m4_default([$$2], [$$1])([$$3])[]]])]) + +# m4_join(SEP, ARG1, ARG2...) +# --------------------------- +# Produce ARG1SEPARG2...SEPARGn. Avoid back-to-back SEP when a given ARG +# is the empty string. No expansion is performed on SEP or ARGs. +# +# Use a self-modifying separator, since we don't know how many +# arguments might be skipped before a separator is first printed, but +# be careful if the separator contains $. _m4_foreach to the rescue. +m4_define([m4_join], +[m4_pushdef([_m4_sep], [m4_define([_m4_sep], _m4_defn([m4_echo]))])]dnl +[_m4_foreach([_$0([$1],], [)], $@)_m4_popdef([_m4_sep])]) + +m4_define([_m4_join], +[m4_if([$2], [], [], [_m4_sep([$1])[$2]])]) + +# m4_joinall(SEP, ARG1, ARG2...) +# ------------------------------ +# Produce ARG1SEPARG2...SEPARGn. An empty ARG results in back-to-back SEP. +# No expansion is performed on SEP or ARGs. +# +# A bit easier than m4_join. _m4_foreach to the rescue. +m4_define([m4_joinall], +[[$2]m4_if(m4_eval([$# <= 2]), [1], [], + [_m4_foreach([$1], [], m4_shift($@))])]) + +# m4_list_cmp(A, B) +# ----------------- +# Compare the two lists of integer expressions A and B. +# +# m4_list_cmp takes care of any side effects; we only override +# _m4_list_cmp_raw, where we can safely expand lists multiple times. +# First, insert padding so that both lists are the same length; the +# trailing +0 is necessary to handle a missing list. Next, create a +# temporary macro to perform pairwise comparisons until an inequality +# is found. For example, m4_list_cmp([1], [1,2]) creates _m4_cmp as +# m4_if(m4_eval([($1) != ($3)]), [1], [m4_cmp([$1], [$3])], +# m4_eval([($2) != ($4)]), [1], [m4_cmp([$2], [$4])], +# [0]_m4_popdef([_m4_cmp])) +# then calls _m4_cmp([1+0], [0*2], [1], [2+0]) +m4_define([_m4_list_cmp_raw], +[m4_if([$1], [$2], 0, + [_m4_list_cmp($1+0_m4_list_pad(m4_count($1), m4_count($2)), + $2+0_m4_list_pad(m4_count($2), m4_count($1)))])]) + +m4_define([_m4_list_pad], +[m4_if(m4_eval($1 < $2), [1], + [_m4_for(m4_incr([$1]), [$2], [1], [,0*])])]) + +m4_define([_m4_list_cmp], +[m4_pushdef([_m4_cmp], [m4_if(]_m4_for( + [1], m4_eval([$# >> 1]), [1], [$0_(], [,]m4_eval([$# >> 1])[)])[ + [0]_m4_popdef([_m4_cmp]))])_m4_cmp($@)]) + +m4_define([_m4_list_cmp_], +[$0_([$1], m4_eval([$1 + $2]))]) + +m4_define([_m4_list_cmp__], +[[m4_eval([($$1) != ($$2)]), [1], [m4_cmp([$$1], [$$2])], +]]) + +# m4_max(EXPR, ...) +# m4_min(EXPR, ...) +# ----------------- +# Return the decimal value of the maximum (or minimum) in a series of +# integer expressions. +# +# _m4_foreach to the rescue; we only need to replace _m4_minmax. Here, +# we need a temporary macro to track the best answer so far, so that +# the foreach expression is tractable. +m4_define([_m4_minmax], +[m4_pushdef([_m4_best], m4_eval([$2]))_m4_foreach( + [m4_define([_m4_best], $1(_m4_best,], [))], m4_shift($@))]dnl +[_m4_best[]_m4_popdef([_m4_best])]) + +# m4_set_add_all(SET, VALUE...) +# ----------------------------- +# Add each VALUE into SET. This is O(n) in the number of VALUEs, and +# can be faster than calling m4_set_add for each VALUE. +# +# _m4_foreach to the rescue. If no deletions have occurred, then +# avoid the speed penalty of m4_set_add. +m4_define([m4_set_add_all], +[m4_if([$#], [0], [], [$#], [1], [], + [m4_define([_m4_set_size($1)], m4_eval(m4_set_size([$1]) + + m4_len(_m4_foreach(m4_ifdef([_m4_set_cleanup($1)], + [[m4_set_add]], [[_$0]])[([$1],], [)], $@))))])]) + +m4_define([_m4_set_add_all], +[m4_ifdef([_m4_set([$1],$2)], [], + [m4_define([_m4_set([$1],$2)], + [1])m4_pushdef([_m4_set([$1])], [$2])-])]) diff --git a/gnuwin32/bin/data/m4sugar/m4sugar.m4 b/gnuwin32/bin/data/m4sugar/m4sugar.m4 new file mode 100644 index 00000000..b732abc7 --- /dev/null +++ b/gnuwin32/bin/data/m4sugar/m4sugar.m4 @@ -0,0 +1,3307 @@ +divert(-1)# -*- Autoconf -*- +# This file is part of Autoconf. +# Base M4 layer. +# Requires GNU M4. +# +# Copyright (C) 1999-2013 Free Software Foundation, Inc. + +# This file is part of Autoconf. 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 3 of the License, 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. +# +# Under Section 7 of GPL version 3, you are granted additional +# permissions described in the Autoconf Configure Script Exception, +# version 3.0, as published by the Free Software Foundation. +# +# You should have received a copy of the GNU General Public License +# and a copy of the Autoconf Configure Script Exception along with +# this program; see the files COPYINGv3 and COPYING.EXCEPTION +# respectively. If not, see <http://www.gnu.org/licenses/>. + +# 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 absolute file 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([to], [from($@)]) +# Well, obviously 1 is more expensive in space. Maybe 2 is more expensive +# 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 would certainly prefer to see `to'. +# +# This definition is in effect during m4sugar initialization, when +# there are no pushdef stacks; later on, we redefine it to something +# more powerful for all other clients to use. +m4_define([m4_copy], +[m4_define([$2], m4_defn([$1]))]) + + +# m4_rename(SRC, DST) +# ------------------- +# Rename the macro SRC to DST. +m4_define([m4_rename], +[m4_copy([$1], [$2])m4_undefine([$1])]) + + +# m4_rename_m4(MACRO-NAME) +# ------------------------ +# Rename MACRO-NAME to m4_MACRO-NAME. +m4_define([m4_rename_m4], +[m4_rename([$1], [m4_$1])]) + + +# m4_copy_unm4(m4_MACRO-NAME) +# --------------------------- +# Copy m4_MACRO-NAME to 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'. Conditionals first, since +# some subsequent renames are conditional. +m4_rename_m4([ifdef]) +m4_rename([ifelse], [m4_if]) + +m4_rename_m4([builtin]) +m4_rename_m4([changecom]) +m4_rename_m4([changequote]) +m4_ifdef([changeword],dnl conditionally available in 1.4.x +[m4_undefine([changeword])]) +m4_rename_m4([debugfile]) +m4_rename_m4([debugmode]) +m4_rename_m4([decr]) +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_undefine([include]) +m4_rename_m4([incr]) +m4_rename_m4([index]) +m4_rename_m4([indir]) +m4_rename_m4([len]) +m4_rename([m4exit], [m4_exit]) +m4_undefine([m4wrap]) +m4_ifdef([mkstemp],dnl added in M4 1.4.8 +[m4_rename_m4([mkstemp]) +m4_copy([m4_mkstemp], [m4_maketemp]) +m4_undefine([maketemp])], +[m4_rename_m4([maketemp]) +m4_copy([m4_maketemp], [m4_mkstemp])]) +m4_rename([patsubst], [m4_bpatsubst]) +m4_rename_m4([popdef]) +m4_rename_m4([pushdef]) +m4_rename([regexp], [m4_bregexp]) +m4_rename_m4([shift]) +m4_undefine([sinclude]) +m4_rename_m4([substr]) +m4_ifdef([symbols],dnl present only in alpha-quality 1.4o +[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_defn(ARG) +# ------------- +# _m4_defn is for internal use only - it bypasses the wrapper, so it +# must only be used on one argument at a time, and only on macros +# known to be defined. Make sure this still works if the user renames +# m4_defn but not _m4_defn. +m4_copy([m4_defn], [_m4_defn]) + +# _m4_divert_raw(NUM) +# ------------------- +# _m4_divert_raw is for internal use only. Use this instead of +# m4_builtin([divert], NUM), so that tracing diversion flow is easier. +m4_rename([divert], [_m4_divert_raw]) + +# _m4_popdef(ARG...) +# ------------------ +# _m4_popdef is for internal use only - it bypasses the wrapper, so it +# must only be used on macros known to be defined. Make sure this +# still works if the user renames m4_popdef but not _m4_popdef. +m4_copy([m4_popdef], [_m4_popdef]) + +# _m4_undefine(ARG...) +# -------------------- +# _m4_undefine is for internal use only - it bypasses the wrapper, so +# it must only be used on macros known to be defined. Make sure this +# still works if the user renames m4_undefine but not _m4_undefine. +m4_copy([m4_undefine], [_m4_undefine]) + +# _m4_undivert(NUM...) +# -------------------- +# _m4_undivert is for internal use only, and should always be given +# arguments. Use this instead of m4_builtin([undivert], NUM...), so +# that tracing diversion flow is easier. +m4_rename([undivert], [_m4_undivert]) + + +## ------------------- ## +## 2. Error messages. ## +## ------------------- ## + + +# m4_location +# ----------- +# Output the current file, colon, and the current line number. +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] +m4_expansion_stack)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. +# If present, STACK-TRACE is a \n-separated list of "LOCATION: MESSAGE", +# where the last line (and no other) ends with "the top level". +# +# Within m4, the macro is a no-op. This macro really matters +# when autom4te post-processes the trace output. +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_expansion_stack]))]) + + + +## ------------------- ## +## 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 +# too many people forget to quote 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) +# ---------------- +# Like the builtin include, but warns against multiple inclusions. +m4_define([m4_include], +[m4_include_unique([$1])dnl +m4_builtin([include], [$1])]) + + +# m4_sinclude(FILE) +# ----------------- +# Like 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 the variation `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_ifblank(COND, [IF-BLANK], [IF-TEXT]) +# m4_ifnblank(COND, [IF-TEXT], [IF-BLANK]) +# ---------------------------------------- +# If COND is empty, or consists only of blanks (space, tab, newline), +# then expand IF-BLANK, otherwise expand IF-TEXT. This differs from +# m4_ifval only if COND has just whitespace, but it helps optimize in +# spite of users who mistakenly leave trailing space after what they +# thought was an empty argument: +# macro( +# [] +# ) +# +# Writing one macro in terms of the other causes extra overhead, so +# we inline both definitions. +m4_define([m4_ifblank], +[m4_if(m4_translit([[$1]], [ ][ ][ +]), [], [$2], [$3])]) + +m4_define([m4_ifnblank], +[m4_if(m4_translit([[$1]], [ ][ ][ +]), [], [$3], [$2])]) + + +# 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_ifval(_m4_defn([$1]), [$2], [$3])], + [$3])]) + + +# m4_ifndef(NAME, [IF-NOT-DEFINED], [IF-DEFINED]) +# ----------------------------------------------- +m4_define([m4_ifndef], +[m4_ifdef([$1], [$3], [$2])]) + + +# m4_case(SWITCH, VAL1, IF-VAL1, VAL2, IF-VAL2, ..., DEFAULT) +# ----------------------------------------------------------- +# m4 equivalent of +# switch (SWITCH) +# { +# case VAL1: +# IF-VAL1; +# break; +# case VAL2: +# IF-VAL2; +# break; +# ... +# default: +# DEFAULT; +# break; +# }. +# All the values are optional, and the macro is robust to active +# symbols properly quoted. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_case], +[m4_if([$#], 0, [], + [$#], 1, [], + [$#], 2, [$2], + [$1], [$2], [$3], + [$0([$1], m4_shift3($@))])]) + + +# 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. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_bmatch], +[m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], + [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], + [$#], 2, [$2], + [m4_if(m4_bregexp([$1], [$2]), -1, [$0([$1], m4_shift3($@))], + [$3])])]) + +# m4_argn(N, ARGS...) +# ------------------- +# Extract argument N (greater than 0) from ARGS. Example: +# m4_define([b], [B]) +# m4_argn([2], [a], [b], [c]) => b +# +# Rather than using m4_car(m4_shiftn([$1], $@)), we exploit the fact that +# GNU m4 can directly reference any argument, through an indirect macro. +m4_define([m4_argn], +[m4_assert([0 < $1])]dnl +[m4_pushdef([_$0], [_m4_popdef([_$0])]m4_dquote([$]m4_incr([$1])))_$0($@)]) + + +# m4_car(ARGS...) +# m4_cdr(ARGS...) +# --------------- +# Manipulate m4 lists. m4_car returns the first argument. m4_cdr +# bundles all but the first argument into a quoted list. These two +# macros are generally used with list arguments, with quoting removed +# to break the list into multiple m4 ARGS. +m4_define([m4_car], [[$1]]) +m4_define([m4_cdr], +[m4_if([$#], 0, [m4_fatal([$0: cannot be called without arguments])], + [$#], 1, [], + [m4_dquote(m4_shift($@))])]) + +# _m4_cdr(ARGS...) +# ---------------- +# Like m4_cdr, except include a leading comma unless only one argument +# remains. Why? Because comparing a large list against [] is more +# expensive in expansion time than comparing the number of arguments; so +# _m4_cdr can be used to reduce the number of arguments when it is time +# to end recursion. +m4_define([_m4_cdr], +[m4_if([$#], 1, [], + [, m4_dquote(m4_shift($@))])]) + + + +# m4_cond(TEST1, VAL1, IF-VAL1, TEST2, VAL2, IF-VAL2, ..., [DEFAULT]) +# ------------------------------------------------------------------- +# Similar to m4_if, except that each TEST is expanded when encountered. +# If the expansion of TESTn matches the string VALn, the result is IF-VALn. +# The result is DEFAULT if no tests passed. This macro allows +# short-circuiting of expensive tests, where it pays to arrange quick +# filter tests to run first. +# +# For an example, consider a previous implementation of _AS_QUOTE_IFELSE: +# +# m4_if(m4_index([$1], [\]), [-1], [$2], +# m4_eval(m4_index([$1], [\\]) >= 0), [1], [$2], +# m4_eval(m4_index([$1], [\$]) >= 0), [1], [$2], +# m4_eval(m4_index([$1], [\`]) >= 0), [1], [$3], +# m4_eval(m4_index([$1], [\"]) >= 0), [1], [$3], +# [$2]) +# +# Here, m4_index is computed 5 times, and m4_eval 4, even if $1 contains +# no backslash. It is more efficient to do: +# +# m4_cond([m4_index([$1], [\])], [-1], [$2], +# [m4_eval(m4_index([$1], [\\]) >= 0)], [1], [$2], +# [m4_eval(m4_index([$1], [\$]) >= 0)], [1], [$2], +# [m4_eval(m4_index([$1], [\`]) >= 0)], [1], [$3], +# [m4_eval(m4_index([$1], [\"]) >= 0)], [1], [$3], +# [$2]) +# +# In the common case of $1 with no backslash, only one m4_index expansion +# occurs, and m4_eval is avoided altogether. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_cond], +[m4_if([$#], [0], [m4_fatal([$0: cannot be called without arguments])], + [$#], [1], [$1], + m4_eval([$# % 3]), [2], [m4_fatal([$0: missing an argument])], + [_$0($@)])]) + +m4_define([_m4_cond], +[m4_if(($1), [($2)], [$3], + [$#], [3], [], + [$#], [4], [$4], + [$0(m4_shift3($@))])]) + + +## ---------------------------------------- ## +## 6. Enhanced version of some primitives. ## +## ---------------------------------------- ## + +# m4_bpatsubsts(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_bpatsubst', unfortunately, +# due to quotation problems, I need to double quote $1 below, therefore +# the anchors are broken :( I can't let users be trapped by that. +# +# Recall that m4_shift3 always results in an argument. Hence, we need +# to distinguish between a final deletion vs. ending recursion. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_bpatsubsts], +[m4_if([$#], 0, [m4_fatal([$0: too few arguments: $#])], + [$#], 1, [m4_fatal([$0: too few arguments: $#: $1])], + [$#], 2, [m4_unquote(m4_builtin([patsubst], [[$1]], [$2]))], + [$#], 3, [m4_unquote(m4_builtin([patsubst], [[$1]], [$2], [$3]))], + [_$0($@m4_if(m4_eval($# & 1), 0, [,]))])]) +m4_define([_m4_bpatsubsts], +[m4_if([$#], 2, [$1], + [$0(m4_builtin([patsubst], [[$1]], [$2], [$3]), + m4_shift3($@))])]) + + +# m4_copy(SRC, DST) +# ----------------- +# Define the pushdef stack DST as a copy of the pushdef stack SRC; +# give an error if DST is already defined. This is particularly nice +# for copying self-modifying pushdef stacks, where the top definition +# includes one-shot initialization that is later popped to the normal +# definition. This version intentionally does nothing if SRC is +# undefined. +# +# Some macros simply can't be renamed with this method: namely, anything +# involved in the implementation of m4_stack_foreach_sep. +m4_define([m4_copy], +[m4_ifdef([$2], [m4_fatal([$0: won't overwrite defined macro: $2])], + [m4_stack_foreach_sep([$1], [m4_pushdef([$2],], [)])])]dnl +[m4_ifdef([m4_location($1)], [m4_define([m4_location($2)], m4_location)])]) + + +# m4_copy_force(SRC, DST) +# m4_rename_force(SRC, DST) +# ------------------------- +# Like m4_copy/m4_rename, except blindly overwrite any existing DST. +# Note that m4_copy_force tolerates undefined SRC, while m4_rename_force +# does not. +m4_define([m4_copy_force], +[m4_ifdef([$2], [_m4_undefine([$2])])m4_copy($@)]) + +m4_define([m4_rename_force], +[m4_ifdef([$2], [_m4_undefine([$2])])m4_rename($@)]) + + +# 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) +# m4_default_nblank(EXP1, EXP2) +# ----------------------------- +# Returns EXP1 if not empty/blank, otherwise EXP2. Expand the result. +# +# m4_default is called on hot paths, so inline the contents of m4_ifval, +# for one less round of expansion. +m4_define([m4_default], +[m4_if([$1], [], [$2], [$1])]) + +m4_define([m4_default_nblank], +[m4_ifblank([$1], [$2], [$1])]) + + +# m4_default_quoted(EXP1, EXP2) +# m4_default_nblank_quoted(EXP1, EXP2) +# ------------------------------------ +# Returns EXP1 if non empty/blank, otherwise EXP2. Leave the result quoted. +# +# For comparison: +# m4_define([active], [ACTIVE]) +# m4_default([active], [default]) => ACTIVE +# m4_default([], [active]) => ACTIVE +# -m4_default([ ], [active])- => - - +# -m4_default_nblank([ ], [active])- => -ACTIVE- +# m4_default_quoted([active], [default]) => active +# m4_default_quoted([], [active]) => active +# -m4_default_quoted([ ], [active])- => - - +# -m4_default_nblank_quoted([ ], [active])- => -active- +# +# m4_default macro is called on hot paths, so inline the contents of m4_ifval, +# for one less round of expansion. +m4_define([m4_default_quoted], +[m4_if([$1], [], [[$2]], [[$1]])]) + +m4_define([m4_default_nblank_quoted], +[m4_ifblank([$1], [[$2]], [[$1]])]) + + +# m4_defn(NAME) +# ------------- +# Like the original, except guarantee a warning when using something which is +# undefined (unlike M4 1.4.x). This replacement is not a full-featured +# replacement: if any of the defined macros contain unbalanced quoting, but +# when pasted together result in a well-quoted string, then only native m4 +# support is able to get it correct. But that's where quadrigraphs come in +# handy, if you really need unbalanced quotes inside your macros. +# +# This macro is called frequently, so minimize the amount of additional +# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, +# (added in M4 1.6), then let m4 do the job for us (see m4_init). +m4_define([m4_defn], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_defn([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_map_args([$0], $@)])]) + + +# m4_dumpdef(NAME...) +# ------------------- +# In m4 1.4.x, dumpdef writes to the current debugfile, rather than +# stderr. This in turn royally confuses autom4te; so we follow the +# lead of newer m4 and always dump to stderr. Unlike the original, +# this version requires an argument, since there is no convenient way +# in m4 1.4.x to grab the names of all defined macros. Newer m4 +# always dumps to stderr, regardless of the current debugfile; it also +# provides m4symbols as a way to grab all current macro names. But +# dumpdefs is not frequently called, so we don't need to worry about +# conditionally using these newer features. Also, this version +# doesn't sort multiple arguments. +# +# If we detect m4 1.6 or newer, then provide an alternate definition, +# installed during m4_init, that allows builtins through. +# Unfortunately, there is no nice way in m4 1.4.x to dump builtins. +m4_define([m4_dumpdef], +[m4_if([$#], [0], [m4_fatal([$0: missing argument])], + [$#], [1], [m4_ifdef([$1], [m4_errprintn( + [$1: ]m4_dquote(_m4_defn([$1])))], [m4_fatal([$0: undefined macro: $1])])], + [m4_map_args([$0], $@)])]) + +m4_define([_m4_dumpdef], +[m4_if([$#], [0], [m4_fatal([$0: missing argument])], + [$#], [1], [m4_builtin([dumpdef], [$1])], + [m4_map_args_sep([m4_builtin([dumpdef],], [)], [], $@)])]) + + +# m4_dumpdefs(NAME...) +# -------------------- +# Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its +# value stack (most recent displayed first). Also, this version silently +# ignores undefined macros, rather than erroring out. +# +# This macro cheats, because it relies on the current definition of NAME +# while the second argument of m4_stack_foreach_lifo is evaluated (which +# would be undefined according to the API). +m4_define([m4_dumpdefs], +[m4_if([$#], [0], [m4_fatal([$0: missing argument])], + [$#], [1], [m4_stack_foreach_lifo([$1], [m4_dumpdef([$1])m4_ignore])], + [m4_map_args([$0], $@)])]) + +# m4_esyscmd_s(COMMAND) +# --------------------- +# Like m4_esyscmd, except strip any trailing newlines, thus behaving +# more like shell command substitution. +m4_define([m4_esyscmd_s], +[m4_chomp_all(m4_esyscmd([$1]))]) + + +# m4_popdef(NAME) +# --------------- +# Like the original, except guarantee a warning when using something which is +# undefined (unlike M4 1.4.x). +# +# This macro is called frequently, so minimize the amount of additional +# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, +# (added in M4 1.6), then let m4 do the job for us (see m4_init). +m4_define([m4_popdef], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_popdef([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_map_args([$0], $@)])]) + + +# m4_shiftn(N, ...) +# ----------------- +# Returns ... shifted N times. Useful for recursive "varargs" constructs. +# +# Autoconf does not use this macro, because it is inherently slower than +# calling the common cases of m4_shift2 or m4_shift3 directly. But it +# might as well be fast for other clients, such as Libtool. One way to +# do this is to expand $@ only once in _m4_shiftn (otherwise, for long +# lists, the expansion of m4_if takes twice as much memory as what the +# list itself occupies, only to throw away the unused branch). The end +# result is strictly equivalent to +# m4_if([$1], 1, [m4_shift(,m4_shift(m4_shift($@)))], +# [_m4_shiftn(m4_decr([$1]), m4_shift(m4_shift($@)))]) +# but with the final `m4_shift(m4_shift($@)))' shared between the two +# paths. The first leg uses a no-op m4_shift(,$@) to balance out the (). +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_shiftn], +[m4_assert(0 < $1 && $1 < $#)_$0($@)]) + +m4_define([_m4_shiftn], +[m4_if([$1], 1, [m4_shift(], + [$0(m4_decr([$1])]), m4_shift(m4_shift($@)))]) + +# m4_shift2(...) +# m4_shift3(...) +# -------------- +# Returns ... shifted twice, and three times. Faster than m4_shiftn. +m4_define([m4_shift2], [m4_shift(m4_shift($@))]) +m4_define([m4_shift3], [m4_shift(m4_shift(m4_shift($@)))]) + +# _m4_shift2(...) +# _m4_shift3(...) +# --------------- +# Like m4_shift2 or m4_shift3, except include a leading comma unless shifting +# consumes all arguments. Why? Because in recursion, it is nice to +# distinguish between 1 element left and 0 elements left, based on how many +# arguments this shift expands to. +m4_define([_m4_shift2], +[m4_if([$#], [2], [], + [, m4_shift(m4_shift($@))])]) +m4_define([_m4_shift3], +[m4_if([$#], [3], [], + [, m4_shift(m4_shift(m4_shift($@)))])]) + + +# m4_undefine(NAME) +# ----------------- +# Like the original, except guarantee a warning when using something which is +# undefined (unlike M4 1.4.x). +# +# This macro is called frequently, so minimize the amount of additional +# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, +# (added in M4 1.6), then let m4 do the job for us (see m4_init). +m4_define([m4_undefine], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_undefine([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_map_args([$0], $@)])]) + +# _m4_wrap(PRE, POST) +# ------------------- +# Helper macro for m4_wrap and m4_wrap_lifo. Allows nested calls to +# m4_wrap within wrapped text. Use _m4_defn and _m4_popdef for speed. +m4_define([_m4_wrap], +[m4_ifdef([$0_text], + [m4_define([$0_text], [$1]_m4_defn([$0_text])[$2])], + [m4_builtin([m4wrap], [m4_unquote( + _m4_defn([$0_text])_m4_popdef([$0_text]))])m4_define([$0_text], [$1$2])])]) + +# m4_wrap(TEXT) +# ------------- +# Append TEXT to the list of hooks to be executed at the end of input. +# Whereas the order of the original may be LIFO in the underlying m4, +# this version is always FIFO. +m4_define([m4_wrap], +[_m4_wrap([], [$1[]])]) + +# m4_wrap_lifo(TEXT) +# ------------------ +# Prepend TEXT to the list of hooks to be executed at the end of input. +# Whereas the order of m4_wrap may be FIFO in the underlying m4, this +# version is always LIFO. +m4_define([m4_wrap_lifo], +[_m4_wrap([$1[]])]) + +## ------------------------- ## +## 7. Quoting manipulation. ## +## ------------------------- ## + + +# m4_apply(MACRO, LIST) +# --------------------- +# Invoke MACRO, with arguments provided from the quoted list of +# comma-separated quoted arguments. If LIST is empty, invoke MACRO +# without arguments. The expansion will not be concatenated with +# subsequent text. +m4_define([m4_apply], +[m4_if([$2], [], [$1], [$1($2)])[]]) + +# _m4_apply(MACRO, LIST) +# ---------------------- +# Like m4_apply, except do nothing if LIST is empty. +m4_define([_m4_apply], +[m4_if([$2], [], [], [$1($2)[]])]) + + +# m4_count(ARGS) +# -------------- +# Return a count of how many ARGS are present. +m4_define([m4_count], [$#]) + + +# m4_curry(MACRO, ARG...) +# ----------------------- +# Perform argument currying. The expansion of this macro is another +# macro that takes exactly one argument, appends it to the end of the +# original ARG list, then invokes MACRO. For example: +# m4_curry([m4_curry], [m4_reverse], [1])([2])([3]) => 3, 2, 1 +# Not quite as practical as m4_incr, but you could also do: +# m4_define([add], [m4_eval(([$1]) + ([$2]))]) +# m4_define([add_one], [m4_curry([add], [1])]) +# add_one()([2]) => 3 +m4_define([m4_curry], [$1(m4_shift($@,)_$0]) +m4_define([_m4_curry], [[$1])]) + + +# m4_do(STRING, ...) +# ------------------ +# This macro invokes all its arguments (in sequence, of course). It is +# useful for making your macros more structured and readable by dropping +# unnecessary dnl's and have the macros indented properly. No concatenation +# occurs after a STRING; use m4_unquote(m4_join(,STRING)) for that. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_do], +[m4_if([$#], 0, [], + [$#], 1, [$1[]], + [$1[]$0(m4_shift($@))])]) + + +# m4_dquote(ARGS) +# --------------- +# Return ARGS as a quoted list of quoted arguments. +m4_define([m4_dquote], [[$@]]) + + +# m4_dquote_elt(ARGS) +# ------------------- +# Return ARGS as an unquoted list of double-quoted arguments. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_dquote_elt], +[m4_if([$#], [0], [], + [$#], [1], [[[$1]]], + [[[$1]],$0(m4_shift($@))])]) + + +# m4_echo(ARGS) +# ------------- +# Return the ARGS, with the same level of quoting. Whitespace after +# unquoted commas are consumed. +m4_define([m4_echo], [$@]) + + +# m4_expand(ARG) +# _m4_expand(ARG) +# --------------- +# Return the expansion of ARG as a single string. Unlike +# m4_quote($1), this preserves whitespace following single-quoted +# commas that appear within ARG. It also deals with shell case +# statements. +# +# m4_define([active], [ACT, IVE]) +# m4_define([active2], [[ACT, IVE]]) +# m4_quote(active, active2) +# => ACT,IVE,ACT, IVE +# m4_expand([active, active2]) +# => ACT, IVE, ACT, IVE +# +# Unfortunately, due to limitations in m4, ARG must expand to +# something with balanced quotes (use quadrigraphs to get around +# this), and should not contain the unlikely delimiters -=<{( or +# )}>=-. It is possible to have unbalanced quoted `(' or `)', as well +# as unbalanced unquoted `)'. m4_expand can handle unterminated +# comments or dnl on the final line, at the expense of speed; it also +# aids in detecting attempts to incorrectly change the current +# diversion inside ARG. Meanwhile, _m4_expand is faster but must be +# given a terminated expansion, and has no safety checks for +# mis-diverted text. +# +# Exploit that extra unquoted () will group unquoted commas and the +# following whitespace. m4_bpatsubst can't handle newlines inside $1, +# and m4_substr strips quoting. So we (ab)use m4_changequote, using +# temporary quotes to remove the delimiters that conveniently included +# the unquoted () that were added prior to the changequote. +# +# Thanks to shell case statements, too many people are prone to pass +# underquoted `)', so we try to detect that by passing a marker as a +# fourth argument; if the marker is not present, then we assume that +# we encountered an early `)', and re-expand the first argument, but +# this time with one more `(' in the second argument and in the +# open-quote delimiter. We must also ignore the slop from the +# previous try. The final macro is thus half line-noise, half art. +m4_define([m4_expand], +[m4_pushdef([m4_divert], _m4_defn([_m4_divert_unsafe]))]dnl +[m4_pushdef([m4_divert_push], _m4_defn([_m4_divert_unsafe]))]dnl +[m4_chomp(_$0([$1 +]))_m4_popdef([m4_divert], [m4_divert_push])]) + +m4_define([_m4_expand], [$0_([$1], [(], -=<{($1)}>=-, [}>=-])]) + +m4_define([_m4_expand_], +[m4_if([$4], [}>=-], + [m4_changequote([-=<{$2], [)}>=-])$3m4_changequote([, ])], + [$0([$1], [($2], -=<{($2$1)}>=-, [}>=-])m4_ignore$2])]) + + +# m4_ignore(ARGS) +# --------------- +# Expands to nothing. Useful for conditionally ignoring an arbitrary +# number of arguments (see _m4_list_cmp for an example). +m4_define([m4_ignore]) + + +# m4_make_list(ARGS) +# ------------------ +# Similar to m4_dquote, this creates a quoted list of quoted ARGS. This +# version is less efficient than m4_dquote, but separates each argument +# with a comma and newline, rather than just comma, for readability. +# When developing an m4sugar algorithm, you could temporarily use +# m4_pushdef([m4_dquote],m4_defn([m4_make_list])) +# around your code to make debugging easier. +m4_define([m4_make_list], [m4_join([, +], m4_dquote_elt($@))]) + + +# m4_noquote(STRING) +# ------------------ +# Return the result of ignoring all quotes in STRING and invoking the +# macros it contains. Among other things, this is useful for enabling +# macro invocations inside strings with [] blocks (for instance regexps +# and help-strings). On the other hand, since all quotes are disabled, +# any macro expanded during this time that relies on nested [] quoting +# will likely crash and burn. This macro is seldom useful; consider +# m4_unquote or m4_expand instead. +m4_define([m4_noquote], +[m4_changequote([-=<{(],[)}>=-])$1-=<{()}>=-m4_changequote([,])]) + + +# m4_quote(ARGS) +# -------------- +# Return ARGS as a single argument. Any whitespace after unquoted commas +# is stripped. There is always output, even when there were no arguments. +# +# It is important to realize the difference between `m4_quote(exp)' and +# `[exp]': in the first case you obtain the quoted *result* of the +# expansion of EXP, while in the latter you just obtain the string +# `exp'. +m4_define([m4_quote], [[$*]]) + + +# _m4_quote(ARGS) +# --------------- +# Like m4_quote, except that when there are no arguments, there is no +# output. For conditional scenarios (such as passing _m4_quote as the +# macro name in m4_mapall), this feature can be used to distinguish between +# one argument of the empty string vs. no arguments. However, in the +# normal case with arguments present, this is less efficient than m4_quote. +m4_define([_m4_quote], +[m4_if([$#], [0], [], [[$*]])]) + + +# m4_reverse(ARGS) +# ---------------- +# Output ARGS in reverse order. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_reverse], +[m4_if([$#], [0], [], [$#], [1], [[$1]], + [$0(m4_shift($@)), [$1]])]) + + +# m4_unquote(ARGS) +# ---------------- +# Remove one layer of quotes from each ARG, performing one level of +# expansion. For one argument, m4_unquote([arg]) is more efficient than +# m4_do([arg]), but for multiple arguments, the difference is that +# m4_unquote separates arguments with commas while m4_do concatenates. +# Follow this macro with [] if concatenation with subsequent text is +# undesired. +m4_define([m4_unquote], [$*]) + + +## -------------------------- ## +## 8. Implementing m4 loops. ## +## -------------------------- ## + + +# m4_for(VARIABLE, FIRST, LAST, [STEP = +/-1], EXPRESSION) +# -------------------------------------------------------- +# Expand EXPRESSION defining VARIABLE to FROM, FROM + 1, ..., TO with +# increments of STEP. Both limits are included, and bounds are +# checked for consistency. The algorithm is robust to indirect +# VARIABLE names. Changing VARIABLE inside EXPRESSION will not impact +# the number of iterations. +# +# Uses _m4_defn for speed, and avoid dnl in the macro body. Factor +# the _m4_for call so that EXPRESSION is only parsed once. +m4_define([m4_for], +[m4_pushdef([$1], m4_eval([$2]))]dnl +[m4_cond([m4_eval(([$3]) > ([$2]))], 1, + [m4_pushdef([_m4_step], m4_eval(m4_default_quoted([$4], + 1)))m4_assert(_m4_step > 0)_$0(_m4_defn([$1]), + m4_eval((([$3]) - ([$2])) / _m4_step * _m4_step + ([$2])), _m4_step,], + [m4_eval(([$3]) < ([$2]))], 1, + [m4_pushdef([_m4_step], m4_eval(m4_default_quoted([$4], + -1)))m4_assert(_m4_step < 0)_$0(_m4_defn([$1]), + m4_eval((([$2]) - ([$3])) / -(_m4_step) * _m4_step + ([$2])), _m4_step,], + [m4_pushdef([_m4_step])_$0(_m4_defn([$1]), _m4_defn([$1]), 0,])]dnl +[[m4_define([$1],], [)$5])m4_popdef([_m4_step], [$1])]) + +# _m4_for(COUNT, LAST, STEP, PRE, POST) +# ------------------------------------- +# Core of the loop, no consistency checks, all arguments are plain +# numbers. Expand PRE[COUNT]POST, then alter COUNT by STEP and +# iterate if COUNT is not LAST. +m4_define([_m4_for], +[$4[$1]$5[]m4_if([$1], [$2], [], + [$0(m4_eval([$1 + $3]), [$2], [$3], [$4], [$5])])]) + + +# Implementing `foreach' loops in m4 is much more tricky than it may +# seem. For example, the old M4 1.4.4 manual had an incorrect example, +# which looked like this (when translated to m4sugar): +# +# | # 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], (m4_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], [(m4_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], [m4_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 nice implementation +# that doesn't require extra parentheses in the user's LIST. +# +# But wait - now the algorithm is quadratic, because every recursion of +# the algorithm keeps the entire LIST and merely adds another m4_shift to +# the quoted text. If the user has a lot of elements in LIST, you can +# bring the system to its knees with the memory m4 then requires, or trip +# the m4 --nesting-limit recursion factor. The only way to avoid +# quadratic growth is ensure m4_shift is expanded prior to the recursion. +# Hence the design below. +# +# The M4 manual now includes a chapter devoted to this issue, with +# the lessons learned from m4sugar. And still, this design is only +# optimal for M4 1.6; see foreach.m4 for yet more comments on why +# M4 1.4.x uses yet another 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- +# +# This macro is called frequently, so avoid extra expansions such as +# m4_ifval and dnl. Also, since $2 might be quite large, try to use it +# as little as possible in _m4_foreach; each extra use requires that much +# more memory for expansion. So, rather than directly compare $2 against +# [] and use m4_car/m4_cdr for recursion, we instead unbox the list (which +# requires swapping the argument order in the helper), insert an ignored +# third argument, and use m4_shift3 to detect when recursion is complete, +# at which point this looks very much like m4_map_args. +m4_define([m4_foreach], +[m4_if([$2], [], [], + [m4_pushdef([$1])_$0([m4_define([$1],], [)$3], [], + $2)m4_popdef([$1])])]) + +# _m4_foreach(PRE, POST, IGNORED, ARG...) +# --------------------------------------- +# Form the common basis of the m4_foreach and m4_map macros. For each +# ARG, expand PRE[ARG]POST[]. The IGNORED argument makes recursion +# easier, and must be supplied rather than implicit. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([_m4_foreach], +[m4_if([$#], [3], [], + [$1[$4]$2[]$0([$1], [$2], m4_shift3($@))])]) + + +# m4_foreach_w(VARIABLE, LIST, EXPRESSION) +# ---------------------------------------- +# Like m4_foreach, but the list is whitespace separated. Depending on +# EXPRESSION, it may be more efficient to use m4_map_args_w. +# +# This macro is robust to active symbols: +# m4_foreach_w([Var], [ active +# b act\ +# ive ], [-Var-])end +# => -active--b--active-end +# +# This used to use a slower implementation based on m4_foreach: +# m4_foreach([$1], m4_split(m4_normalize([$2]), [ ]), [$3]) +m4_define([m4_foreach_w], +[m4_pushdef([$1])m4_map_args_w([$2], + [m4_define([$1],], [)$3])m4_popdef([$1])]) + + +# m4_map(MACRO, LIST) +# m4_mapall(MACRO, LIST) +# ---------------------- +# Invoke MACRO($1), MACRO($2) etc. where $1, $2... are the elements of +# LIST. $1, $2... must in turn be lists, appropriate for m4_apply. +# If LIST contains an empty sublist, m4_map skips the expansion of +# MACRO, while m4_mapall expands MACRO with no arguments. +# +# Since LIST may be quite large, we want to minimize how often it +# appears in the expansion. Rather than use m4_car/m4_cdr iteration, +# we unbox the list, and use _m4_foreach for iteration. For m4_map, +# an empty list behaves like an empty sublist and gets ignored; for +# m4_mapall, we must special-case the empty list. +m4_define([m4_map], +[_m4_foreach([_m4_apply([$1],], [)], [], $2)]) + +m4_define([m4_mapall], +[m4_if([$2], [], [], + [_m4_foreach([m4_apply([$1],], [)], [], $2)])]) + + +# m4_map_sep(MACRO, [SEPARATOR], LIST) +# m4_mapall_sep(MACRO, [SEPARATOR], LIST) +# --------------------------------------- +# Invoke MACRO($1), SEPARATOR, MACRO($2), ..., MACRO($N) where $1, +# $2... $N are the elements of LIST, and are in turn lists appropriate +# for m4_apply. SEPARATOR is expanded, in order to allow the creation +# of a list of arguments by using a single-quoted comma as the +# separator. For each empty sublist, m4_map_sep skips the expansion +# of MACRO and SEPARATOR, while m4_mapall_sep expands MACRO with no +# arguments. +# +# For m4_mapall_sep, merely expand the first iteration without the +# separator, then include separator as part of subsequent recursion; +# but avoid extra expansion of LIST's side-effects via a helper macro. +# For m4_map_sep, things are trickier - we don't know if the first +# list element is an empty sublist, so we must define a self-modifying +# helper macro and use that as the separator instead. +m4_define([m4_map_sep], +[m4_pushdef([m4_Sep], [m4_define([m4_Sep], _m4_defn([m4_unquote]))])]dnl +[_m4_foreach([_m4_apply([m4_Sep([$2])[]$1],], [)], [], $3)m4_popdef([m4_Sep])]) + +m4_define([m4_mapall_sep], +[m4_if([$3], [], [], [_$0([$1], [$2], $3)])]) + +m4_define([_m4_mapall_sep], +[m4_apply([$1], [$3])_m4_foreach([m4_apply([$2[]$1],], [)], m4_shift2($@))]) + +# m4_map_args(EXPRESSION, ARG...) +# ------------------------------- +# Expand EXPRESSION([ARG]) for each argument. More efficient than +# m4_foreach([var], [ARG...], [EXPRESSION(m4_defn([var]))]) +# Shorthand for m4_map_args_sep([EXPRESSION(], [)], [], ARG...). +m4_define([m4_map_args], +[m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], + [$#], [1], [], + [$#], [2], [$1([$2])[]], + [_m4_foreach([$1(], [)], $@)])]) + + +# m4_map_args_pair(EXPRESSION, [END-EXPR = EXPRESSION], ARG...) +# ------------------------------------------------------------- +# Perform a pairwise grouping of consecutive ARGs, by expanding +# EXPRESSION([ARG1], [ARG2]). If there are an odd number of ARGs, the +# final argument is expanded with END-EXPR([ARGn]). +# +# For example: +# m4_define([show], [($*)m4_newline])dnl +# m4_map_args_pair([show], [], [a], [b], [c], [d], [e])dnl +# => (a,b) +# => (c,d) +# => (e) +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_map_args_pair], +[m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], + [$#], [1], [m4_fatal([$0: too few arguments: $#: $1])], + [$#], [2], [], + [$#], [3], [m4_default([$2], [$1])([$3])[]], + [$#], [4], [$1([$3], [$4])[]], + [$1([$3], [$4])[]$0([$1], [$2], m4_shift(m4_shift3($@)))])]) + + +# m4_map_args_sep([PRE], [POST], [SEP], ARG...) +# --------------------------------------------- +# Expand PRE[ARG]POST for each argument, with SEP between arguments. +m4_define([m4_map_args_sep], +[m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], + [$#], [1], [], + [$#], [2], [], + [$#], [3], [], + [$#], [4], [$1[$4]$2[]], + [$1[$4]$2[]_m4_foreach([$3[]$1], [$2], m4_shift3($@))])]) + + +# m4_map_args_w(STRING, [PRE], [POST], [SEP]) +# ------------------------------------------- +# Perform the expansion of PRE[word]POST[] for each word in STRING +# separated by whitespace. More efficient than: +# m4_foreach_w([var], [STRING], [PRE[]m4_defn([var])POST]) +# Additionally, expand SEP between words. +# +# As long as we have to use m4_bpatsubst to split the string, we might +# as well make it also apply PRE and POST; this avoids iteration +# altogether. But we must be careful of any \ in PRE or POST. +# _m4_strip returns a quoted string, but that's okay, since it also +# supplies an empty leading and trailing argument due to our +# intentional whitespace around STRING. We use m4_substr to strip the +# empty elements and remove the extra layer of quoting. +m4_define([m4_map_args_w], +[_$0(_m4_split([ ]m4_flatten([$1])[ ], [[ ]+], + m4_if(m4_index([$2$3$4], [\]), [-1], [[$3[]$4[]$2]], + [m4_bpatsubst([[$3[]$4[]$2]], [\\], [\\\\])])), + m4_len([[]$3[]$4]), m4_len([$4[]$2[]]))]) + +m4_define([_m4_map_args_w], +[m4_substr([$1], [$2], m4_eval(m4_len([$1]) - [$2] - [$3]))]) + + +# m4_stack_foreach(MACRO, FUNC) +# m4_stack_foreach_lifo(MACRO, FUNC) +# ---------------------------------- +# Pass each stacked definition of MACRO to the one-argument macro FUNC. +# m4_stack_foreach proceeds in FIFO order, while m4_stack_foreach_lifo +# processes the topmost definitions first. In addition, FUNC should +# not push or pop definitions of MACRO, and should not expect anything about +# the active definition of MACRO (it will not be the topmost, and may not +# be the one passed to FUNC either). +# +# Some macros simply can't be examined with this method: namely, +# anything involved in the implementation of _m4_stack_reverse. +m4_define([m4_stack_foreach], +[_m4_stack_reverse([$1], [m4_tmp-$1])]dnl +[_m4_stack_reverse([m4_tmp-$1], [$1], [$2(_m4_defn([m4_tmp-$1]))])]) + +m4_define([m4_stack_foreach_lifo], +[_m4_stack_reverse([$1], [m4_tmp-$1], [$2(_m4_defn([m4_tmp-$1]))])]dnl +[_m4_stack_reverse([m4_tmp-$1], [$1])]) + +# m4_stack_foreach_sep(MACRO, [PRE], [POST], [SEP]) +# m4_stack_foreach_sep_lifo(MACRO, [PRE], [POST], [SEP]) +# ------------------------------------------------------ +# Similar to m4_stack_foreach and m4_stack_foreach_lifo, in that every +# definition of a pushdef stack will be visited. But rather than +# passing the definition as a single argument to a macro, this variant +# expands the concatenation of PRE[]definition[]POST, and expands SEP +# between consecutive expansions. Note that m4_stack_foreach([a], [b]) +# is equivalent to m4_stack_foreach_sep([a], [b(], [)]). +m4_define([m4_stack_foreach_sep], +[_m4_stack_reverse([$1], [m4_tmp-$1])]dnl +[_m4_stack_reverse([m4_tmp-$1], [$1], [$2[]_m4_defn([m4_tmp-$1])$3], [$4[]])]) + +m4_define([m4_stack_foreach_sep_lifo], +[_m4_stack_reverse([$1], [m4_tmp-$1], [$2[]_m4_defn([m4_tmp-$1])$3], [$4[]])]dnl +[_m4_stack_reverse([m4_tmp-$1], [$1])]) + + +# _m4_stack_reverse(OLD, NEW, [ACTION], [SEP]) +# -------------------------------------------- +# A recursive worker for pushdef stack manipulation. Destructively +# copy the OLD stack into the NEW, and expanding ACTION for each +# iteration. After the first iteration, SEP is promoted to the front +# of ACTION (note that SEP should include a trailing [] if it is to +# avoid interfering with ACTION). The current definition is examined +# after the NEW has been pushed but before OLD has been popped; this +# order is important, as ACTION is permitted to operate on either +# _m4_defn([OLD]) or _m4_defn([NEW]). Since the operation is +# destructive, this macro is generally used twice, with a temporary +# macro name holding the swapped copy. +m4_define([_m4_stack_reverse], +[m4_ifdef([$1], [m4_pushdef([$2], + _m4_defn([$1]))$3[]_m4_popdef([$1])$0([$1], [$2], [$4$3])])]) + + + +## --------------------------- ## +## 9. More diversion support. ## +## --------------------------- ## + + +# m4_cleardivert(DIVERSION-NAME...) +# --------------------------------- +# Discard any text in DIVERSION-NAME. +# +# This works even inside m4_expand. +m4_define([m4_cleardivert], +[m4_if([$#], [0], [m4_fatal([$0: missing argument])], + [_m4_divert_raw([-1])m4_undivert($@)_m4_divert_raw( + _m4_divert(_m4_defn([_m4_divert_diversion]), [-]))])]) + + +# _m4_divert(DIVERSION-NAME or NUMBER, [NOWARN]) +# ---------------------------------------------- +# If DIVERSION-NAME is the name of a diversion, return its number, +# otherwise if it is a NUMBER return it. Issue a warning about +# the use of a number instead of a name, unless NOWARN is provided. +m4_define([_m4_divert], +[m4_ifdef([_m4_divert($1)], + [m4_indir([_m4_divert($1)])], + [m4_if([$2], [], [m4_warn([syntax], + [prefer named diversions])])$1])]) + +# KILL is only used to suppress output. +m4_define([_m4_divert(KILL)], -1) + +# The empty diversion name is a synonym for 0. +m4_define([_m4_divert()], 0) + + +# m4_divert_stack +# --------------- +# Print the diversion stack, if it's nonempty. The caller is +# responsible for any leading or trailing newline. +m4_define([m4_divert_stack], +[m4_stack_foreach_sep_lifo([_m4_divert_stack], [], [], [ +])]) + + +# m4_divert_stack_push(MACRO-NAME, DIVERSION-NAME) +# ------------------------------------------------ +# Form an entry of the diversion stack from caller MACRO-NAME and +# entering DIVERSION-NAME and push it. +m4_define([m4_divert_stack_push], +[m4_pushdef([_m4_divert_stack], m4_location[: $1: $2])]) + + +# m4_divert(DIVERSION-NAME) +# ------------------------- +# Change the diversion stream to DIVERSION-NAME. +m4_define([m4_divert], +[m4_popdef([_m4_divert_stack])]dnl +[m4_define([_m4_divert_diversion], [$1])]dnl +[m4_divert_stack_push([$0], [$1])]dnl +[_m4_divert_raw(_m4_divert([$1]))]) + + +# m4_divert_push(DIVERSION-NAME, [NOWARN]) +# ---------------------------------------- +# Change the diversion stream to DIVERSION-NAME, while stacking old values. +# For internal use only: if NOWARN is not empty, DIVERSION-NAME can be a +# number instead of a name. +m4_define([m4_divert_push], +[m4_divert_stack_push([$0], [$1])]dnl +[m4_pushdef([_m4_divert_diversion], [$1])]dnl +[_m4_divert_raw(_m4_divert([$1], [$2]))]) + + +# m4_divert_pop([DIVERSION-NAME]) +# ------------------------------- +# Change the diversion stream to its previous value, unstacking it. +# If specified, verify we left DIVERSION-NAME. +# When we pop the last value from the stack, we divert to -1. +m4_define([m4_divert_pop], +[m4_if([$1], [], [], + [$1], _m4_defn([_m4_divert_diversion]), [], + [m4_fatal([$0($1): diversion mismatch: +]m4_divert_stack)])]dnl +[_m4_popdef([_m4_divert_stack], [_m4_divert_diversion])]dnl +[m4_ifdef([_m4_divert_diversion], [], + [m4_fatal([too many m4_divert_pop])])]dnl +[_m4_divert_raw(_m4_divert(_m4_defn([_m4_divert_diversion]), [-]))]) + + +# 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])$2 +m4_divert_pop([$1])]) + + +# m4_divert_once(DIVERSION-NAME, CONTENT) +# --------------------------------------- +# Output CONTENT into DIVERSION-NAME once, if not already there. +# An end of line is appended for free to CONTENT. +m4_define([m4_divert_once], +[m4_expand_once([m4_divert_text([$1], [$2])])]) + + +# _m4_divert_unsafe(DIVERSION-NAME) +# --------------------------------- +# Issue a warning that the attempt to change the current diversion to +# DIVERSION-NAME is unsafe, because this macro is being expanded +# during argument collection of m4_expand. +m4_define([_m4_divert_unsafe], +[m4_fatal([$0: cannot change diversion to `$1' inside m4_expand])]) + + +# m4_undivert(DIVERSION-NAME...) +# ------------------------------ +# Undivert DIVERSION-NAME. Unlike the M4 version, this requires at +# least one DIVERSION-NAME; also, due to support for named diversions, +# this should not be used to undivert files. +m4_define([m4_undivert], +[m4_if([$#], [0], [m4_fatal([$0: missing argument])], + [$#], [1], [_m4_undivert(_m4_divert([$1]))], + [m4_map_args([$0], $@)])]) + + +## --------------------------------------------- ## +## 10. 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 calls m4_provide, 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 three ideas, (i) using diversions to +# prepare the expansion of the macro and its dependencies (by Franc,ois +# Pinard), (ii) expand the most recently m4_require'd macros _after_ +# the previous macros (by Axel Thimm), and (iii) track instances of +# provide before require (by Eric Blake). +# +# +# The first idea: why use 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...m4_require([TEST2])1]) +# | m4_defun([TEST2], [Test...m4_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 levels 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], [m4_require([TEST2a])m4_require([TEST2b])]) +# | m4_defun([TEST2a], []) +# | m4_defun([TEST2b], [m4_require([TEST3])]) +# | m4_defun([TEST3], [m4_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, we use 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 macros are expanded. (The bug above can +# indeed be described as: a macro has been m4_provide'd before its +# dependent, but it is emitted after: the lack of correlation between +# emission and expansion order is guilty). +# +# How to do that? You keep 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 involved. 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 implementation tries not to assume that 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 +# are 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 _m4_divert_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 +# _m4_require_call m4_divert_pushes another temporary diversion, +# GROW - 1, and expands TEST2a in there. +# DUMP: BODY +# BODY: empty +# GROW - 1: TEST2a +# diversions: GROW - 1, GROW, BODY |- +# Then the content of the temporary diversion is moved to DUMP and the +# temporary diversion is popped. +# DUMP: BODY +# BODY: TEST2a +# diversions: GROW, BODY |- +# +# * TEST1 requires TEST2b +# Again, _m4_require_call pushes GROW - 1 and heads to expand TEST2b. +# DUMP: BODY +# BODY: TEST2a +# diversions: GROW - 1, GROW, BODY |- +# +# * TEST2b requires TEST3 +# _m4_require_call pushes GROW - 2 and expands TEST3 here. +# (TEST3 requires TEST2a, but TEST2a has already been m4_provide'd, so +# nothing happens.) +# DUMP: BODY +# BODY: TEST2a +# GROW - 2: TEST3 +# diversions: GROW - 2, GROW - 1, GROW, BODY |- +# Then the diversion is appended to DUMP, and popped. +# DUMP: BODY +# BODY: TEST2a; TEST3 +# diversions: GROW - 1, GROW, BODY |- +# +# * TEST1 requires TEST2b (contd.) +# The content of TEST2b is expanded... +# DUMP: BODY +# BODY: TEST2a; TEST3 +# GROW - 1: TEST2b, +# diversions: GROW - 1, GROW, BODY |- +# ... and moved to DUMP. +# DUMP: BODY +# BODY: TEST2a; TEST3; TEST2b +# diversions: GROW, BODY |- +# +# * TEST1 is expanded: epilogue +# TEST1's own content is in GROW... +# DUMP: BODY +# BODY: TEST2a; TEST3; TEST2b +# GROW: TEST1 +# diversions: BODY |- +# ... and it's epilogue moves it to DUMP and then undefines DUMP. +# DUMP: undefined +# BODY: TEST2a; TEST3; TEST2b; TEST1 +# diversions: BODY |- +# +# +# The third idea: track macros provided before they were required +# --------------------------------------------------------------- +# +# Using just the first two ideas, Autoconf 2.50 through 2.63 still had +# a subtle bug for more than seven years. Let's consider the +# following example to explain the bug: +# +# | m4_defun([TEST1], [1]) +# | m4_defun([TEST2], [2[]m4_require([TEST1])]) +# | m4_defun([TEST3], [3 TEST1 m4_require([TEST2])]) +# | TEST3 +# +# After the prologue of TEST3, we are collecting text in GROW with the +# intent of dumping it in BODY during the epilogue. Next, we +# encounter the direct invocation of TEST1, which provides the macro +# in place in GROW. From there, we encounter a requirement for TEST2, +# which must be collected in a new diversion. While expanding TEST2, +# we encounter a requirement for TEST1, but since it has already been +# expanded, the Axel Thimm algorithm states that we can treat it as a +# no-op. But that would lead to an end result of `2 3 1', meaning +# that we have once again output a macro (TEST2) prior to its +# requirements (TEST1). +# +# The problem can only occur if a single defun'd macro first provides, +# then later indirectly requires, the same macro. Note that directly +# expanding then requiring a macro is okay: because the dependency was +# met, the require phase can be a no-op. For that matter, the outer +# macro can even require two helpers, where the first helper expands +# the macro, and the second helper indirectly requires the macro. +# Out-of-order expansion is only present if the inner macro is +# required by something that will be hoisted in front of where the +# direct expansion occurred. In other words, we must be careful not +# to warn on: +# +# | m4_defun([TEST4], [4]) +# | m4_defun([TEST5], [5 TEST4 m4_require([TEST4])]) +# | TEST5 => 5 4 +# +# or even the more complex: +# +# | m4_defun([TEST6], [6]) +# | m4_defun([TEST7], [7 TEST6]) +# | m4_defun([TEST8], [8 m4_require([TEST6])]) +# | m4_defun([TEST9], [9 m4_require([TEST8])]) +# | m4_defun([TEST10], [10 m4_require([TEST7]) m4_require([TEST9])]) +# | TEST10 => 7 6 8 9 10 +# +# So, to detect whether a require was direct or indirect, m4_defun and +# m4_require track the name of the macro that caused a diversion to be +# created (using the stack _m4_diverting, coupled with an O(1) lookup +# _m4_diverting([NAME])), and m4_provide stores the name associated +# with the diversion at which a macro was provided. A require call is +# direct if it occurs within the same diversion where the macro was +# provided, or if the diversion associated with the providing context +# has been collected. +# +# The implementation of the warning involves tracking the set of +# macros which have been provided since the start of the outermost +# defun'd macro (the set is named _m4_provide). When starting an +# outermost macro, the set is emptied; when a macro is provided, it is +# added to the set; when require expands the body of a macro, it is +# removed from the set; and when a macro is indirectly required, the +# set is checked. If a macro is in the set, then it has been provided +# before it was required, and we satisfy dependencies by expanding the +# macro as if it had never been provided; in the example given above, +# this means we now output `1 2 3 1'. Meanwhile, a warning is issued +# to inform the user that her macros trigger the bug in older autoconf +# versions, and that her output file now contains redundant contents +# (and possibly new problems, if the repeated macro was not +# idempotent). Meanwhile, macros defined by m4_defun_once instead of +# m4_defun are idempotent, avoiding any warning or duplicate output. +# +# +# 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. +# +# Each time we enter an m4_defun'd macros, we add a definition in +# _m4_expansion_stack, and when we exit the macro, we remove it (thanks +# to pushdef/popdef). m4_stack_foreach is used to print the expansion +# stack in the rare cases when it's needed. +# +# In addition, we want to detect circular m4_require dependencies. +# Each time we expand a macro FOO we define _m4_expanding(FOO); and +# m4_require(BAR) simply checks whether _m4_expanding(BAR) is defined. + + +# m4_expansion_stack +# ------------------ +# Expands to the entire contents of the expansion stack. The caller +# must supply a trailing newline. This macro always prints a +# location; check whether _m4_expansion_stack is defined to filter out +# the case when no defun'd macro is in force. +m4_define([m4_expansion_stack], +[m4_stack_foreach_sep_lifo([_$0], [_$0_entry(], [) +])m4_location[: the top level]]) + +# _m4_expansion_stack_entry(MACRO) +# -------------------------------- +# Format an entry for MACRO found on the expansion stack. +m4_define([_m4_expansion_stack_entry], +[_m4_defn([m4_location($1)])[: $1 is expanded from...]]) + +# m4_expansion_stack_push(MACRO) +# ------------------------------ +# Form an entry of the expansion stack on entry to MACRO and push it. +m4_define([m4_expansion_stack_push], +[m4_pushdef([_m4_expansion_stack], [$1])]) + + +# _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. +# +# This is called frequently, so minimize the number of macro invocations +# by avoiding dnl and m4_defn overhead. +m4_define([_m4_defun_pro], +[m4_ifdef([_m4_expansion_stack], [], [_m4_defun_pro_outer([$1])])]dnl +[m4_expansion_stack_push([$1])m4_pushdef([_m4_expanding($1)])]) + +m4_define([_m4_defun_pro_outer], +[m4_set_delete([_m4_provide])]dnl +[m4_pushdef([_m4_diverting([$1])])m4_pushdef([_m4_diverting], [$1])]dnl +[m4_pushdef([_m4_divert_dump], m4_divnum)m4_divert_push([GROW])]) + +# _m4_defun_epi(MACRO-NAME) +# ------------------------- +# The Epilogue for Autoconf macros. MACRO-NAME only helps tracing +# the PRO/EPI pairs. +# +# This is called frequently, so minimize the number of macro invocations +# by avoiding dnl and m4_popdef overhead. +m4_define([_m4_defun_epi], +[_m4_popdef([_m4_expanding($1)], [_m4_expansion_stack])]dnl +[m4_ifdef([_m4_expansion_stack], [], [_m4_defun_epi_outer([$1])])]dnl +[m4_provide([$1])]) + +m4_define([_m4_defun_epi_outer], +[_m4_popdef([_m4_divert_dump], [_m4_diverting([$1])], [_m4_diverting])]dnl +[m4_divert_pop([GROW])m4_undivert([GROW])]) + + +# _m4_divert_dump +# --------------- +# If blank, we are outside of any defun'd macro. Otherwise, expands +# to the diversion number (not name) where require'd macros should be +# moved once completed. +m4_define([_m4_divert_dump]) + + +# m4_divert_require(DIVERSION, NAME-TO-CHECK, [BODY-TO-EXPAND]) +# ------------------------------------------------------------- +# Same as m4_require, but BODY-TO-EXPAND goes into the named DIVERSION; +# requirements still go in the current diversion though. +# +m4_define([m4_divert_require], +[m4_ifdef([_m4_expanding($2)], + [m4_fatal([$0: circular dependency of $2])])]dnl +[m4_if(_m4_divert_dump, [], + [m4_fatal([$0($2): cannot be used outside of an m4_defun'd macro])])]dnl +[m4_provide_if([$2], [], + [_m4_require_call([$2], [$3], _m4_divert([$1], [-]))])]) + + +# m4_defun(NAME, EXPANSION, [MACRO = m4_define]) +# ---------------------------------------------- +# Define a macro NAME which automatically provides itself. Add +# machinery so the macro automatically switches expansion to the +# diversion stack if it is not already using it, prior to EXPANSION. +# 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. +# +# MACRO is an undocumented argument; when set to m4_pushdef, and NAME +# is already defined, the new definition is added to the pushdef +# stack, rather than overwriting the current definition. It can thus +# be used to write self-modifying macros, which pop themselves to a +# previously m4_define'd definition so that subsequent use of the +# macro is faster. +m4_define([m4_defun], +[m4_define([m4_location($1)], m4_location)]dnl +[m4_default([$3], [m4_define])([$1], + [_m4_defun_pro(]m4_dquote($[0])[)$2[]_m4_defun_epi(]m4_dquote($[0])[)])]) + + +# m4_defun_init(NAME, INIT, COMMON) +# --------------------------------- +# Like m4_defun, but split EXPANSION into two portions: INIT which is +# done only the first time NAME is invoked, and COMMON which is +# expanded every time. +# +# For now, the COMMON definition is always m4_define'd, giving an even +# lighter-weight definition. m4_defun allows self-providing, but once +# a macro is provided, m4_require no longer cares if it is m4_define'd +# or m4_defun'd. m4_defun also provides location tracking to identify +# dependency bugs, but once the INIT has been expanded, we know there +# are no dependency bugs. However, if a future use needs COMMON to be +# m4_defun'd, we can add a parameter, similar to the third parameter +# to m4_defun. +m4_define([m4_defun_init], +[m4_define([$1], [$3[]])m4_defun([$1], + [$2[]_m4_popdef(]m4_dquote($[0])[)m4_indir(]m4_dquote($[0])dnl +[m4_if(]m4_dquote($[#])[, [0], [], ]m4_dquote([,$]@)[))], [m4_pushdef])]) + + +# m4_defun_once(NAME, EXPANSION) +# ------------------------------ +# Like m4_defun, but guarantee that EXPANSION only happens once +# (thereafter, using NAME is a no-op). +# +# If _m4_divert_dump is empty, we are called at the top level; +# otherwise, we must ensure that we are required in front of the +# current defun'd macro. Use a helper macro so that EXPANSION need +# only occur once in the definition of NAME, since it might be large. +m4_define([m4_defun_once], +[m4_define([m4_location($1)], m4_location)]dnl +[m4_define([$1], [_m4_defun_once([$1], [$2], m4_if(_m4_divert_dump, [], + [[_m4_defun_pro([$1])m4_unquote(], [)_m4_defun_epi([$1])]], +m4_ifdef([_m4_diverting([$1])], [-]), [-], [[m4_unquote(], [)]], + [[_m4_require_call([$1],], [, _m4_divert_dump)]]))])]) + +m4_define([_m4_defun_once], +[m4_pushdef([$1])$3[$2[]m4_provide([$1])]$4]) + + +# m4_pattern_forbid(ERE, [WHY]) +# ----------------------------- +# Declare that no token matching the forbidden extended regular +# expression ERE should be seen in the output unless... +m4_define([m4_pattern_forbid], []) + + +# m4_pattern_allow(ERE) +# --------------------- +# ... that token also matches the allowed extended regular expression ERE. +# Both used via traces. +m4_define([m4_pattern_allow], []) + + +## --------------------------------- ## +## 11. Dependencies between macros. ## +## --------------------------------- ## + + +# m4_before(THIS-MACRO-NAME, CALLED-MACRO-NAME) +# --------------------------------------------- +# Issue a warning if CALLED-MACRO-NAME was called before THIS-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; follow the expansion with a newline. 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(threads.h)], [AC_CHECK_HEADERS(threads.h)]) +# which is just the same as +# m4_require([AC_PROG_CC]) +# m4_require([AC_CHECK_HEADERS(threads.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)'. +# +# This is called frequently, so minimize the number of macro invocations +# by avoiding dnl and other overhead on the common path. +m4_define([m4_require], +[m4_ifdef([_m4_expanding($1)], + [m4_fatal([$0: circular dependency of $1])])]dnl +[m4_if(_m4_divert_dump, [], + [m4_fatal([$0($1): cannot be used outside of an ]dnl +m4_if([$0], [m4_require], [[m4_defun]], [[AC_DEFUN]])['d macro])])]dnl +[m4_provide_if([$1], [m4_set_contains([_m4_provide], [$1], + [_m4_require_check([$1], _m4_defn([m4_provide($1)]), [$0])], [m4_ignore])], + [_m4_require_call])([$1], [$2], _m4_divert_dump)]) + + +# _m4_require_call(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK], +# DIVERSION-NUMBER) +# ----------------------------------------------------------------- +# If m4_require decides to expand the body, it calls this macro. The +# expansion is placed in DIVERSION-NUMBER. +# +# This is called frequently, so minimize the number of macro invocations +# by avoiding dnl and other overhead on the common path. +# The use of a witness macro protecting the warning allows aclocal +# to silence any warnings when probing for what macros are required +# and must therefore be located, when using the Autoconf-without-aclocal-m4 +# autom4te language. For more background, see: +# https://lists.gnu.org/archive/html/automake-patches/2012-11/msg00035.html +m4_define([_m4_require_call], +[m4_pushdef([_m4_divert_grow], m4_decr(_m4_divert_grow))]dnl +[m4_pushdef([_m4_diverting([$1])])m4_pushdef([_m4_diverting], [$1])]dnl +[m4_divert_push(_m4_divert_grow, [-])]dnl +[m4_if([$2], [], [$1], [$2]) +m4_provide_if([$1], [m4_set_remove([_m4_provide], [$1])], + [m4_ifndef([m4_require_silent_probe], + [m4_warn([syntax], [$1 is m4_require'd but not m4_defun'd])])])]dnl +[_m4_divert_raw($3)_m4_undivert(_m4_divert_grow)]dnl +[m4_divert_pop(_m4_divert_grow)_m4_popdef([_m4_divert_grow], +[_m4_diverting([$1])], [_m4_diverting])]) + + +# _m4_require_check(NAME-TO-CHECK, OWNER, CALLER) +# ----------------------------------------------- +# NAME-TO-CHECK has been identified as previously expanded in the +# diversion owned by OWNER. If this is a problem, warn on behalf of +# CALLER and return _m4_require_call; otherwise return m4_ignore. +m4_define([_m4_require_check], +[m4_if(_m4_defn([_m4_diverting]), [$2], [m4_ignore], + m4_ifdef([_m4_diverting([$2])], [-]), [-], [m4_warn([syntax], + [$3: `$1' was expanded before it was required +http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required])_m4_require_call], + [m4_ignore])]) + + +# _m4_divert_grow +# --------------- +# The counter for _m4_require_call. +m4_define([_m4_divert_grow], _m4_divert([GROW])) + + +# 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_default_quoted([$2], [$1]), + [], + [m4_provide(m4_default_quoted([$2], [$1]))[]$1])]) + + +# m4_provide(MACRO-NAME) +# ---------------------- +m4_define([m4_provide], +[m4_ifdef([m4_provide($1)], [], +[m4_set_add([_m4_provide], [$1], [m4_define([m4_provide($1)], + m4_ifdef([_m4_diverting], [_m4_defn([_m4_diverting])]))])])]) + + +# 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])]) + + +## --------------------- ## +## 12. 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_alnum +# ----------- +m4_define([m4_cr_alnum], +m4_defn([m4_cr_Letters])dnl +m4_defn([m4_cr_digits])dnl +) + + +# 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_cr_all +# --------- +# The character range representing everything, with `-' as the last +# character, since it is special to m4_translit. Use with care, because +# it contains characters special to M4 (fortunately, both ASCII and EBCDIC +# have [] in order, so m4_defn([m4_cr_all]) remains a valid string). It +# also contains characters special to terminals, so it should never be +# displayed in an error message. Also, attempts to map [ and ] to other +# characters via m4_translit must deal with the fact that m4_translit does +# not add quotes to the output. +# +# In EBCDIC, $ is immediately followed by *, which leads to problems +# if m4_cr_all is inlined into a macro definition; so swap them. +# +# It is mainly useful in generating inverted character range maps, for use +# in places where m4_translit is faster than an equivalent m4_bpatsubst; +# the regex `[^a-z]' is equivalent to: +# m4_translit(m4_dquote(m4_defn([m4_cr_all])), [a-z]) +m4_define([m4_cr_all], +m4_translit(m4_dquote(m4_format(m4_dquote(m4_for( + ,1,255,,[[%c]]))m4_for([i],1,255,,[,i]))), [$*-], [*$])-) + + +# _m4_define_cr_not(CATEGORY) +# --------------------------- +# Define m4_cr_not_CATEGORY as the inverse of m4_cr_CATEGORY. +m4_define([_m4_define_cr_not], +[m4_define([m4_cr_not_$1], + m4_translit(m4_dquote(m4_defn([m4_cr_all])), + m4_defn([m4_cr_$1])))]) + + +# m4_cr_not_letters +# m4_cr_not_LETTERS +# m4_cr_not_Letters +# m4_cr_not_digits +# m4_cr_not_alnum +# m4_cr_not_symbols1 +# m4_cr_not_symbols2 +# ------------------ +# Inverse character sets +_m4_define_cr_not([letters]) +_m4_define_cr_not([LETTERS]) +_m4_define_cr_not([Letters]) +_m4_define_cr_not([digits]) +_m4_define_cr_not([alnum]) +_m4_define_cr_not([symbols1]) +_m4_define_cr_not([symbols2]) + + +# m4_newline([STRING]) +# -------------------- +# Expands to a newline, possibly followed by STRING. Exists mostly for +# formatting reasons. +m4_define([m4_newline], [ +$1]) + + +# m4_re_escape(STRING) +# -------------------- +# Escape RE active characters in STRING. +m4_define([m4_re_escape], +[m4_bpatsubst([$1], + [[][*+.?\^$]], [\\\&])]) + + +# m4_re_string +# ------------ +# Regexp for `[a-zA-Z_0-9]*' +# m4_dquote provides literal [] for the character class. +m4_define([m4_re_string], +m4_dquote(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_dquote(m4_defn([m4_cr_symbols1]))dnl +m4_defn([m4_re_string])dnl +) + + +# m4_tolower(STRING) +# m4_toupper(STRING) +# ------------------ +# These macros convert STRING to lowercase or uppercase. +# +# Rather than expand the m4_defn each time, we inline them up front. +m4_define([m4_tolower], +[m4_translit([[$1]], ]m4_dquote(m4_defn([m4_cr_LETTERS]))[, + ]m4_dquote(m4_defn([m4_cr_letters]))[)]) +m4_define([m4_toupper], +[m4_translit([[$1]], ]m4_dquote(m4_defn([m4_cr_letters]))[, + ]m4_dquote(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 ]+. +# +# If STRING is empty, the result is an empty list. +# +# Pay attention to the m4_changequotes. When m4 reads the definition of +# m4_split, it still has quotes set to [ and ]. Luckily, these are matched +# in the macro body, so the definition is stored correctly. Use the same +# alternate quotes as m4_noquote; it must be unlikely to appear in $1. +# +# 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 +# +# Optimize on regex of ` ' (space), since m4_foreach_w already guarantees +# that the list contains single space separators, and a common case is +# splitting a single-element list. This macro is called frequently, +# so avoid unnecessary dnl inside the definition. +m4_define([m4_split], +[m4_if([$1], [], [], + [$2], [ ], [m4_if(m4_index([$1], [ ]), [-1], [[[$1]]], + [_$0([$1], [$2], [, ])])], + [$2], [], [_$0([$1], [[ ]+], [, ])], + [_$0([$1], [$2], [, ])])]) + +m4_define([_m4_split], +[m4_changequote([-=<{(],[)}>=-])]dnl +[[m4_bpatsubst(-=<{(-=<{($1)}>=-)}>=-, -=<{($2)}>=-, + -=<{(]$3[)}>=-)]m4_changequote([, ])]) + + +# m4_chomp(STRING) +# m4_chomp_all(STRING) +# -------------------- +# Return STRING quoted, but without a trailing newline. m4_chomp +# removes at most one newline, while m4_chomp_all removes all +# consecutive trailing newlines. Embedded newlines are not touched, +# and a trailing backslash-newline leaves just a trailing backslash. +# +# m4_bregexp is slower than m4_index, and we don't always want to +# remove all newlines; hence the two variants. We massage characters +# to give a nicer pattern to match, particularly since m4_bregexp is +# line-oriented. Both versions must guarantee a match, to avoid bugs +# with precision -1 in m4_format in older m4. +m4_define([m4_chomp], +[m4_format([[%.*s]], m4_index(m4_translit([[$1]], [ +/.], [/ ])[./.], [/.]), [$1])]) + +m4_define([m4_chomp_all], +[m4_format([[%.*s]], m4_bregexp(m4_translit([[$1]], [ +/], [/ ]), [/*$]), [$1])]) + + +# 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 +# +# In m4, m4_bpatsubst is expensive, so first check for a newline. +m4_define([m4_flatten], +[m4_if(m4_index([$1], [ +]), [-1], [[$1]], + [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 <tab> <tab>active ])end +# => active activeend +# +# First, notice that we guarantee trailing space. Why? Because regular +# expressions are greedy, and `.* ?' would always group the space into the +# .* portion. The algorithm is simpler by avoiding `?' at the end. The +# algorithm correctly strips everything if STRING is just ` '. +# +# Then notice the second pattern: it is in charge of removing the +# leading/trailing spaces. Why not just `[^ ]'? Because they are +# applied to over-quoted strings, i.e. more or less [STRING], due +# to the limitations of m4_bpatsubsts. So the leading space in STRING +# is the *second* character; equally for the trailing space. +m4_define([m4_strip], +[m4_bpatsubsts([$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. Avoid back-to-back SEP when a given ARG +# is the empty string. No expansion is performed on SEP or ARGs. +# +# Since the number of arguments to join can be arbitrarily long, we +# want to avoid having more than one $@ in the macro definition; +# otherwise, the expansion would require twice the memory of the already +# long list. Hence, m4_join merely looks for the first non-empty element, +# and outputs just that element; while _m4_join looks for all non-empty +# elements, and outputs them following a separator. The final trick to +# note is that we decide between recursing with $0 or _$0 based on the +# nested m4_if ending with `_'. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_join], +[m4_if([$#], [1], [], + [$#], [2], [[$2]], + [m4_if([$2], [], [], [[$2]_])$0([$1], m4_shift2($@))])]) +m4_define([_m4_join], +[m4_if([$#$2], [2], [], + [m4_if([$2], [], [], [[$1$2]])$0([$1], m4_shift2($@))])]) + +# m4_joinall(SEP, ARG1, ARG2...) +# ------------------------------ +# Produce ARG1SEPARG2...SEPARGn. An empty ARG results in back-to-back SEP. +# No expansion is performed on SEP or ARGs. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_joinall], [[$2]_$0([$1], m4_shift($@))]) +m4_define([_m4_joinall], +[m4_if([$#], [2], [], [[$1$3]$0([$1], m4_shift2($@))])]) + +# m4_combine([SEPARATOR], PREFIX-LIST, [INFIX], SUFFIX...) +# -------------------------------------------------------- +# Produce the pairwise combination of every element in the quoted, +# comma-separated PREFIX-LIST with every element from the SUFFIX arguments. +# Each pair is joined with INFIX, and pairs are separated by SEPARATOR. +# No expansion occurs on SEPARATOR, INFIX, or elements of either list. +# +# For example: +# m4_combine([, ], [[a], [b], [c]], [-], [1], [2], [3]) +# => a-1, a-2, a-3, b-1, b-2, b-3, c-1, c-2, c-3 +# +# This definition is a bit hairy; the thing to realize is that we want +# to construct m4_map_args_sep([[prefix$3]], [], [[$1]], m4_shift3($@)) +# as the inner loop, using each prefix generated by the outer loop, +# and without recalculating m4_shift3 every outer iteration. +m4_define([m4_combine], +[m4_if([$2], [], [], m4_eval([$# > 3]), [1], +[m4_map_args_sep([m4_map_args_sep(m4_dquote(], [)[[$3]], [], [[$1]],]]]dnl +[m4_dquote(m4_dquote(m4_shift3($@)))[[)], [[$1]], $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'. +# +# Note that neither STRING nor SEPARATOR are expanded here; rather, when +# you expand MACRO-NAME, they will be expanded at that point in time. +# +# This macro is robust to active symbols. It can be used to grow +# strings. +# +# | m4_define(active, ACTIVE)dnl +# | m4_append([sentence], [This is an])dnl +# | m4_append([sentence], [ active ])dnl +# | m4_append([sentence], [symbol.])dnl +# | 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)dnl +# | m4_append([hooks], [m4_define([act1], [act2])])dnl +# | m4_append([hooks], [m4_define([act2], [active])])dnl +# | m4_undefine([active])dnl +# | act1 +# | hooks +# | act1 +# => act1 +# => +# => active +# +# It can also be used to create lists, although this particular usage was +# broken prior to autoconf 2.62. +# | m4_append([list], [one], [, ])dnl +# | m4_append([list], [two], [, ])dnl +# | m4_append([list], [three], [, ])dnl +# | list +# | m4_dquote(list) +# => one, two, three +# => [one],[two],[three] +# +# Note that m4_append can benefit from amortized O(n) m4 behavior, if +# the underlying m4 implementation is smart enough to avoid copying existing +# contents when enlarging a macro's definition into any pre-allocated storage +# (m4 1.4.x unfortunately does not implement this optimization). We do +# not implement m4_prepend, since it is inherently O(n^2) (pre-allocated +# storage only occurs at the end of a macro, so the existing contents must +# always be moved). +# +# Use _m4_defn for speed. +m4_define([m4_append], +[m4_define([$1], m4_ifdef([$1], [_m4_defn([$1])[$3]])[$2])]) + + +# m4_append_uniq(MACRO-NAME, STRING, [SEPARATOR], [IF-UNIQ], [IF-DUP]) +# -------------------------------------------------------------------- +# Like `m4_append', but append only if not yet present. Additionally, +# expand IF-UNIQ if STRING was appended, or IF-DUP if STRING was already +# present. Also, warn if SEPARATOR is not empty and occurs within STRING, +# as the algorithm no longer guarantees uniqueness. +# +# Note that while m4_append can be O(n) (depending on the quality of the +# underlying M4 implementation), m4_append_uniq is inherently O(n^2) +# because each append operation searches the entire string. +m4_define([m4_append_uniq], +[m4_ifval([$3], [m4_if(m4_index([$2], [$3]), [-1], [], + [m4_warn([syntax], + [$0: `$2' contains `$3'])])])_$0($@)]) +m4_define([_m4_append_uniq], +[m4_ifdef([$1], + [m4_if(m4_index([$3]_m4_defn([$1])[$3], [$3$2$3]), [-1], + [m4_append([$1], [$2], [$3])$4], [$5])], + [m4_define([$1], [$2])$4])]) + +# m4_append_uniq_w(MACRO-NAME, STRINGS) +# ------------------------------------- +# For each of the words in the whitespace separated list STRINGS, append +# only the unique strings to the definition of MACRO-NAME. +# +# Use _m4_defn for speed. +m4_define([m4_append_uniq_w], +[m4_map_args_w([$2], [_m4_append_uniq([$1],], [, [ ])])]) + + +# m4_escape(STRING) +# ----------------- +# Output quoted STRING, but with embedded #, $, [ and ] turned into +# quadrigraphs. +# +# It is faster to check if STRING is already good using m4_translit +# than to blindly perform four m4_bpatsubst. +# +# Because the translit is stripping quotes, it must also neutralize +# anything that might be in a macro name, as well as comments, commas, +# and parentheses. All the problem characters are unified so that a +# single m4_index can scan the result. +# +# Rather than expand m4_defn every time m4_escape is expanded, we +# inline its expansion up front. +m4_define([m4_escape], +[m4_if(m4_index(m4_translit([$1], + [[]#,()]]m4_dquote(m4_defn([m4_cr_symbols2]))[, [$$$]), [$]), + [-1], [m4_echo], [_$0])([$1])]) + +m4_define([_m4_escape], +[m4_changequote([-=<{(],[)}>=-])]dnl +[m4_bpatsubst(m4_bpatsubst(m4_bpatsubst(m4_bpatsubst( + -=<{(-=<{(-=<{(-=<{(-=<{($1)}>=-)}>=-)}>=-)}>=-)}>=-, + -=<{(#)}>=-, -=<{(@%:@)}>=-), + -=<{(\[)}>=-, -=<{(@<:@)}>=-), + -=<{(\])}>=-, -=<{(@:>@)}>=-), + -=<{(\$)}>=-, -=<{(@S|@)}>=-)m4_changequote([,])]) + + +# m4_text_wrap(STRING, [PREFIX], [FIRST-PREFIX], [WIDTH]) +# ------------------------------------------------------- +# Expands into STRING wrapped to hold in WIDTH columns (default = 79). +# If PREFIX is given, 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 FIRST-PREFIX is greater than that of PREFIX, then +# FIRST-PREFIX will be left alone on the first line. +# +# No expansion occurs on the contents STRING, PREFIX, or FIRST-PREFIX, +# although quadrigraphs are correctly recognized. More precisely, +# you may redefine m4_qlen to recognize whatever escape sequences that +# you will post-process. +# +# 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 of a line, +# which complicates it a bit. The algorithm is otherwise stupid and 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. +# +# The algorithm uses a helper that uses $2 through $4 directly, rather than +# using local variables, to avoid m4_defn overhead, or expansion swallowing +# any $. It also bypasses m4_popdef overhead with _m4_popdef since no user +# macro expansion occurs in the meantime. Also, the definition is written +# with m4_do, to avoid time wasted on dnl during expansion (since this is +# already a time-consuming macro). +m4_define([m4_text_wrap], +[_$0(m4_escape([$1]), [$2], m4_default_quoted([$3], [$2]), + m4_default_quoted([$4], [79]))]) + +m4_define([_m4_text_wrap], +m4_do(dnl set up local variables, to avoid repeated calculations +[[m4_pushdef([m4_Indent], m4_qlen([$2]))]], +[[m4_pushdef([m4_Cursor], m4_qlen([$3]))]], +[[m4_pushdef([m4_Separator], [m4_define([m4_Separator], [ ])])]], +dnl expand the first prefix, then check its length vs. regular prefix +dnl same length: nothing special +dnl prefix1 longer: output on line by itself, and reset cursor +dnl prefix1 shorter: pad to length of prefix, and reset cursor +[[[$3]m4_cond([m4_Cursor], m4_Indent, [], + [m4_eval(m4_Cursor > m4_Indent)], [1], [ +[$2]m4_define([m4_Cursor], m4_Indent)], + [m4_format([%*s], m4_max([0], + m4_eval(m4_Indent - m4_Cursor)), [])m4_define([m4_Cursor], m4_Indent)])]], +dnl now, for each word, compute the cursor after the word is output, then +dnl check if the cursor would exceed the wrap column +dnl if so, reset cursor, and insert newline and prefix +dnl if not, insert the separator (usually a space) +dnl either way, insert the word +[[m4_map_args_w([$1], [$0_word(], [, [$2], [$4])])]], +dnl finally, clean up the local variables +[[_m4_popdef([m4_Separator], [m4_Cursor], [m4_Indent])]])) + +m4_define([_m4_text_wrap_word], +[m4_define([m4_Cursor], m4_eval(m4_Cursor + m4_qlen([$1]) + 1))]dnl +[m4_if(m4_eval(m4_Cursor > ([$3])), + [1], [m4_define([m4_Cursor], m4_eval(m4_Indent + m4_qlen([$1]) + 1)) +[$2]], + [m4_Separator[]])[$1]]) + +# m4_text_box(MESSAGE, [FRAME-CHARACTER = `-']) +# --------------------------------------------- +# Turn MESSAGE into: +# ## ------- ## +# ## MESSAGE ## +# ## ------- ## +# using FRAME-CHARACTER in the border. +# +# Quadrigraphs are correctly recognized. More precisely, you may +# redefine m4_qlen to recognize whatever escape sequences that you +# will post-process. +m4_define([m4_text_box], +[m4_pushdef([m4_Border], + m4_translit(m4_format([[[%*s]]], m4_decr(m4_qlen(_m4_expand([$1 +]))), []), [ ], m4_default_quoted([$2], [-])))]dnl +[[##] _m4_defn([m4_Border]) [##] +[##] $1 [##] +[##] _m4_defn([m4_Border]) [##]_m4_popdef([m4_Border])]) + + +# m4_qlen(STRING) +# --------------- +# Expands to the length of STRING after autom4te converts all quadrigraphs. +# +# If you use some other means of post-processing m4 output rather than +# autom4te, then you may redefine this macro to recognize whatever +# escape sequences your post-processor will handle. For that matter, +# m4_define([m4_qlen], m4_defn([m4_len])) is sufficient if you don't +# do any post-processing. +# +# Avoid bpatsubsts for the common case of no quadrigraphs. Cache +# results, as configure scripts tend to ask about lengths of common +# strings like `/*' and `*/' rather frequently. Minimize the number +# of times that $1 occurs in m4_qlen, so there is less text to parse +# on a cache hit. +m4_define([m4_qlen], +[m4_ifdef([$0-$1], [_m4_defn([$0-]], [_$0(])[$1])]) +m4_define([_m4_qlen], +[m4_define([m4_qlen-$1], +m4_if(m4_index([$1], [@]), [-1], [m4_len([$1])], + [m4_len(m4_bpatsubst([[$1]], + [@\(\(<:\|:>\|S|\|%:\|\{:\|:\}\)\(@\)\|&t@\)], + [\3]))]))_m4_defn([m4_qlen-$1])]) + +# m4_copyright_condense(TEXT) +# --------------------------- +# Condense the copyright notice in TEXT to only display the final +# year, wrapping the results to fit in 80 columns. +m4_define([m4_copyright_condense], +[m4_text_wrap(m4_bpatsubst(m4_flatten([[$1]]), +[(C)[- ,0-9]*\([1-9][0-9][0-9][0-9]\)], [(C) \1]))]) + +## ----------------------- ## +## 13. Number processing. ## +## ----------------------- ## + +# m4_cmp(A, B) +# ------------ +# Compare two integer expressions. +# A < B -> -1 +# A = B -> 0 +# A > B -> 1 +m4_define([m4_cmp], +[m4_eval((([$1]) > ([$2])) - (([$1]) < ([$2])))]) + + +# m4_list_cmp(A, B) +# ----------------- +# +# Compare the two lists of integer expressions 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([xa], [oops])dnl +# m4_list_cmp([[0xa]], [5+5]) -> 0 +# +# Rather than face the overhead of m4_case, we use a helper function whose +# expansion includes the name of the macro to invoke on the tail, either +# m4_ignore or m4_unquote. This is particularly useful when comparing +# long lists, since less text is being expanded for deciding when to end +# recursion. The recursion is between a pair of macros that alternate +# which list is trimmed by one element; this is more efficient than +# calling m4_cdr on both lists from a single macro. Guarantee exactly +# one expansion of both lists' side effects. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_list_cmp], +[_$0_raw(m4_dquote($1), m4_dquote($2))]) + +m4_define([_m4_list_cmp_raw], +[m4_if([$1], [$2], [0], [_m4_list_cmp_1([$1], $2)])]) + +m4_define([_m4_list_cmp], +[m4_if([$1], [], [0m4_ignore], [$2], [0], [m4_unquote], [$2m4_ignore])]) + +m4_define([_m4_list_cmp_1], +[_m4_list_cmp_2([$2], [m4_shift2($@)], $1)]) + +m4_define([_m4_list_cmp_2], +[_m4_list_cmp([$1$3], m4_cmp([$3+0], [$1+0]))( + [_m4_list_cmp_1(m4_dquote(m4_shift3($@)), $2)])]) + +# m4_max(EXPR, ...) +# m4_min(EXPR, ...) +# ----------------- +# Return the decimal value of the maximum (or minimum) in a series of +# integer expressions. +# +# M4 1.4.x doesn't provide ?:. Hence this huge m4_eval. Avoid m4_eval +# if both arguments are identical, but be aware of m4_max(0xa, 10) (hence +# the use of <=, not just <, in the second multiply). +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_max], +[m4_if([$#], [0], [m4_fatal([too few arguments to $0])], + [$#], [1], [m4_eval([$1])], + [$#$1], [2$2], [m4_eval([$1])], + [$#], [2], [_$0($@)], + [_m4_minmax([_$0], $@)])]) + +m4_define([_m4_max], +[m4_eval((([$1]) > ([$2])) * ([$1]) + (([$1]) <= ([$2])) * ([$2]))]) + +m4_define([m4_min], +[m4_if([$#], [0], [m4_fatal([too few arguments to $0])], + [$#], [1], [m4_eval([$1])], + [$#$1], [2$2], [m4_eval([$1])], + [$#], [2], [_$0($@)], + [_m4_minmax([_$0], $@)])]) + +m4_define([_m4_min], +[m4_eval((([$1]) < ([$2])) * ([$1]) + (([$1]) >= ([$2])) * ([$2]))]) + +# _m4_minmax(METHOD, ARG1, ARG2...) +# --------------------------------- +# Common recursion code for m4_max and m4_min. METHOD must be _m4_max +# or _m4_min, and there must be at least two arguments to combine. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([_m4_minmax], +[m4_if([$#], [3], [$1([$2], [$3])], + [$0([$1], $1([$2], [$3]), m4_shift3($@))])]) + + +# m4_sign(A) +# ---------- +# The sign of the integer expression A. +m4_define([m4_sign], +[m4_eval((([$1]) > 0) - (([$1]) < 0))]) + + + +## ------------------------ ## +## 14. Version processing. ## +## ------------------------ ## + + +# m4_version_unletter(VERSION) +# ---------------------------- +# Normalize beta version numbers with letters to numeric expressions, which +# can then be handed to m4_eval for the purpose of comparison. +# +# Nl -> (N+1).-1.(l#) +# +# for example: +# [2.14a] -> [0,2,14+1,-1,[0r36:a]] -> 2.15.-1.10 +# [2.14b] -> [0,2,15+1,-1,[0r36:b]] -> 2.15.-1.11 +# [2.61aa.b] -> [0,2.61,1,-1,[0r36:aa],+1,-1,[0r36:b]] -> 2.62.-1.370.1.-1.11 +# [08] -> [0,[0r10:0]8] -> 8 +# +# This macro expects reasonable version numbers, but can handle double +# letters and does not expand any macros. Original version strings can +# use both `.' and `-' separators. +# +# Inline constant expansions, to avoid m4_defn overhead. +# _m4_version_unletter is the real workhorse used by m4_version_compare, +# but since [0r36:a] and commas are less readable than 10 and dots, we +# provide a wrapper for human use. +m4_define([m4_version_unletter], +[m4_substr(m4_map_args([.m4_eval], m4_unquote(_$0([$1]))), [3])]) +m4_define([_m4_version_unletter], +[m4_bpatsubst(m4_bpatsubst(m4_translit([[[[0,$1]]]], [.-], [,,]),]dnl +m4_dquote(m4_dquote(m4_defn([m4_cr_Letters])))[[+], + [+1,-1,[0r36:\&]]), [,0], [,[0r10:0]])]) + + +# 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 > +# +# Since _m4_version_unletter does not output side effects, we can +# safely bypass the overhead of m4_version_cmp. +m4_define([m4_version_compare], +[_m4_list_cmp_raw(_m4_version_unletter([$1]), _m4_version_unletter([$2]))]) + + +# m4_PACKAGE_NAME +# m4_PACKAGE_TARNAME +# m4_PACKAGE_VERSION +# m4_PACKAGE_STRING +# m4_PACKAGE_BUGREPORT +# -------------------- +# If m4sugar/version.m4 is present, then define version strings. This +# file is optional, provided by Autoconf but absent in Bison. +m4_sinclude([m4sugar/version.m4]) + + +# m4_version_prereq(VERSION, [IF-OK], [IF-NOT = FAIL]) +# ---------------------------------------------------- +# Check this Autoconf version against VERSION. +m4_define([m4_version_prereq], +m4_ifdef([m4_PACKAGE_VERSION], +[[m4_if(m4_version_compare(]m4_dquote(m4_defn([m4_PACKAGE_VERSION]))[, [$1]), + [-1], + [m4_default([$3], + [m4_fatal([Autoconf version $1 or higher is required], + [63])])], + [$2])]], +[[m4_fatal([m4sugar/version.m4 not found])]])) + + +## ------------------ ## +## 15. Set handling. ## +## ------------------ ## + +# Autoconf likes to create arbitrarily large sets; for example, as of +# this writing, the configure.ac for coreutils tracks a set of more +# than 400 AC_SUBST. How do we track all of these set members, +# without introducing duplicates? We could use m4_append_uniq, with +# the set NAME residing in the contents of the macro NAME. +# Unfortunately, m4_append_uniq is quadratic for set creation, because +# it costs O(n) to search the string for each of O(n) insertions; not +# to mention that with m4 1.4.x, even using m4_append is slow, costing +# O(n) rather than O(1) per insertion. Other set operations, not used +# by Autoconf but still possible by manipulation of the definition +# tracked in macro NAME, include O(n) deletion of one element and O(n) +# computation of set size. Because the set is exposed to the user via +# the definition of a single macro, we cannot cache any data about the +# set without risking the cache being invalidated by the user +# redefining NAME. +# +# Can we do better? Yes, because m4 gives us an O(1) search function +# for free: ifdef. Additionally, even m4 1.4.x gives us an O(1) +# insert operation for free: pushdef. But to use these, we must +# represent the set via a group of macros; to keep the set consistent, +# we must hide the set so that the user can only manipulate it through +# accessor macros. The contents of the set are maintained through two +# access points; _m4_set([name]) is a pushdef stack of values in the +# set, useful for O(n) traversal of the set contents; while the +# existence of _m4_set([name],value) with no particular value is +# useful for O(1) querying of set membership. And since the user +# cannot externally manipulate the set, we are free to add additional +# caching macros for other performance improvements. Deletion can be +# O(1) per element rather than O(n), by reworking the definition of +# _m4_set([name],value) to be 0 or 1 based on current membership, and +# adding _m4_set_cleanup(name) to defer the O(n) cleanup of +# _m4_set([name]) until we have another reason to do an O(n) +# traversal. The existence of _m4_set_cleanup(name) can then be used +# elsewhere to determine if we must dereference _m4_set([name],value), +# or assume that definition implies set membership. Finally, size can +# be tracked in an O(1) fashion with _m4_set_size(name). +# +# The quoting in _m4_set([name],value) is chosen so that there is no +# ambiguity with a set whose name contains a comma, and so that we can +# supply the value via _m4_defn([_m4_set([name])]) without needing any +# quote manipulation. + +# m4_set_add(SET, VALUE, [IF-UNIQ], [IF-DUP]) +# ------------------------------------------- +# Add VALUE as an element of SET. Expand IF-UNIQ on the first +# addition, and IF-DUP if it is already in the set. Addition of one +# element is O(1), such that overall set creation is O(n). +# +# We do not want to add a duplicate for a previously deleted but +# unpruned element, but it is just as easy to check existence directly +# as it is to query _m4_set_cleanup($1). +m4_define([m4_set_add], +[m4_ifdef([_m4_set([$1],$2)], + [m4_if(m4_indir([_m4_set([$1],$2)]), [0], + [m4_define([_m4_set([$1],$2)], + [1])_m4_set_size([$1], [m4_incr])$3], [$4])], + [m4_define([_m4_set([$1],$2)], + [1])m4_pushdef([_m4_set([$1])], + [$2])_m4_set_size([$1], [m4_incr])$3])]) + +# m4_set_add_all(SET, VALUE...) +# ----------------------------- +# Add each VALUE into SET. This is O(n) in the number of VALUEs, and +# can be faster than calling m4_set_add for each VALUE. +# +# Implement two recursion helpers; the check variant is slower but +# handles the case where an element has previously been removed but +# not pruned. The recursion helpers ignore their second argument, so +# that we can use the faster m4_shift2 and 2 arguments, rather than +# _m4_shift2 and one argument, as the signal to end recursion. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_set_add_all], +[m4_define([_m4_set_size($1)], m4_eval(m4_set_size([$1]) + + m4_len(m4_ifdef([_m4_set_cleanup($1)], [_$0_check], [_$0])([$1], $@))))]) + +m4_define([_m4_set_add_all], +[m4_if([$#], [2], [], + [m4_ifdef([_m4_set([$1],$3)], [], + [m4_define([_m4_set([$1],$3)], [1])m4_pushdef([_m4_set([$1])], + [$3])-])$0([$1], m4_shift2($@))])]) + +m4_define([_m4_set_add_all_check], +[m4_if([$#], [2], [], + [m4_set_add([$1], [$3])$0([$1], m4_shift2($@))])]) + +# m4_set_contains(SET, VALUE, [IF-PRESENT], [IF-ABSENT]) +# ------------------------------------------------------ +# Expand IF-PRESENT if SET contains VALUE, otherwise expand IF-ABSENT. +# This is always O(1). +m4_define([m4_set_contains], +[m4_ifdef([_m4_set_cleanup($1)], + [m4_if(m4_ifdef([_m4_set([$1],$2)], + [m4_indir([_m4_set([$1],$2)])], [0]), [1], [$3], [$4])], + [m4_ifdef([_m4_set([$1],$2)], [$3], [$4])])]) + +# m4_set_contents(SET, [SEP]) +# --------------------------- +# Expand to a single string containing all the elements in SET, +# separated by SEP, without modifying SET. No provision is made for +# disambiguating set elements that contain non-empty SEP as a +# sub-string, or for recognizing a set that contains only the empty +# string. Order of the output is not guaranteed. If any elements +# have been previously removed from the set, this action will prune +# the unused memory. This is O(n) in the size of the set before +# pruning. +# +# Use _m4_popdef for speed. The existence of _m4_set_cleanup($1) +# determines which version of _1 helper we use. +m4_define([m4_set_contents], +[m4_set_map_sep([$1], [], [], [[$2]])]) + +# _m4_set_contents_1(SET) +# _m4_set_contents_1c(SET) +# _m4_set_contents_2(SET, [PRE], [POST], [SEP]) +# --------------------------------------------- +# Expand to a list of quoted elements currently in the set, each +# surrounded by PRE and POST, and moving SEP in front of PRE on +# recursion. To avoid nesting limit restrictions, the algorithm must +# be broken into two parts; _1 destructively copies the stack in +# reverse into _m4_set_($1), producing no output; then _2 +# destructively copies _m4_set_($1) back into the stack in reverse. +# If no elements were deleted, then this visits the set in the order +# that elements were inserted. Behavior is undefined if PRE/POST/SEP +# tries to recursively list or modify SET in any way other than +# calling m4_set_remove on the current element. Use _1 if all entries +# in the stack are guaranteed to be in the set, and _1c to prune +# removed entries. Uses _m4_defn and _m4_popdef for speed. +m4_define([_m4_set_contents_1], +[_m4_stack_reverse([_m4_set([$1])], [_m4_set_($1)])]) + +m4_define([_m4_set_contents_1c], +[m4_ifdef([_m4_set([$1])], + [m4_set_contains([$1], _m4_defn([_m4_set([$1])]), + [m4_pushdef([_m4_set_($1)], _m4_defn([_m4_set([$1])]))], + [_m4_popdef([_m4_set([$1],]_m4_defn( + [_m4_set([$1])])[)])])_m4_popdef([_m4_set([$1])])$0([$1])], + [_m4_popdef([_m4_set_cleanup($1)])])]) + +m4_define([_m4_set_contents_2], +[_m4_stack_reverse([_m4_set_($1)], [_m4_set([$1])], + [$2[]_m4_defn([_m4_set_($1)])$3], [$4[]])]) + +# m4_set_delete(SET) +# ------------------ +# Delete all elements in SET, and reclaim any memory occupied by the +# set. This is O(n) in the set size. +# +# Use _m4_defn and _m4_popdef for speed. +m4_define([m4_set_delete], +[m4_ifdef([_m4_set([$1])], + [_m4_popdef([_m4_set([$1],]_m4_defn([_m4_set([$1])])[)], + [_m4_set([$1])])$0([$1])], + [m4_ifdef([_m4_set_cleanup($1)], + [_m4_popdef([_m4_set_cleanup($1)])])m4_ifdef( + [_m4_set_size($1)], + [_m4_popdef([_m4_set_size($1)])])])]) + +# m4_set_difference(SET1, SET2) +# ----------------------------- +# Produce a LIST of quoted elements that occur in SET1 but not SET2. +# Output a comma prior to any elements, to distinguish the empty +# string from no elements. This can be directly used as a series of +# arguments, such as for m4_join, or wrapped inside quotes for use in +# m4_foreach. Order of the output is not guaranteed. +# +# Short-circuit the idempotence relation. +m4_define([m4_set_difference], +[m4_if([$1], [$2], [], [m4_set_map_sep([$1], [_$0([$2],], [)])])]) + +m4_define([_m4_set_difference], +[m4_set_contains([$1], [$2], [], [,[$2]])]) + +# m4_set_dump(SET, [SEP]) +# ----------------------- +# Expand to a single string containing all the elements in SET, +# separated by SEP, then delete SET. In general, if you only need to +# list the contents once, this is faster than m4_set_contents. No +# provision is made for disambiguating set elements that contain +# non-empty SEP as a sub-string. Order of the output is not +# guaranteed. This is O(n) in the size of the set before pruning. +# +# Use _m4_popdef for speed. Use existence of _m4_set_cleanup($1) to +# decide if more expensive recursion is needed. +m4_define([m4_set_dump], +[m4_ifdef([_m4_set_size($1)], + [_m4_popdef([_m4_set_size($1)])])m4_ifdef([_m4_set_cleanup($1)], + [_$0_check], [_$0])([$1], [], [$2])]) + +# _m4_set_dump(SET, [SEP], [PREP]) +# _m4_set_dump_check(SET, [SEP], [PREP]) +# -------------------------------------- +# Print SEP and the current element, then delete the element and +# recurse with empty SEP changed to PREP. The check variant checks +# whether the element has been previously removed. Use _m4_defn and +# _m4_popdef for speed. +m4_define([_m4_set_dump], +[m4_ifdef([_m4_set([$1])], + [[$2]_m4_defn([_m4_set([$1])])_m4_popdef([_m4_set([$1],]_m4_defn( + [_m4_set([$1])])[)], [_m4_set([$1])])$0([$1], [$2$3])])]) + +m4_define([_m4_set_dump_check], +[m4_ifdef([_m4_set([$1])], + [m4_set_contains([$1], _m4_defn([_m4_set([$1])]), + [[$2]_m4_defn([_m4_set([$1])])])_m4_popdef( + [_m4_set([$1],]_m4_defn([_m4_set([$1])])[)], + [_m4_set([$1])])$0([$1], [$2$3])], + [_m4_popdef([_m4_set_cleanup($1)])])]) + +# m4_set_empty(SET, [IF-EMPTY], [IF-ELEMENTS]) +# -------------------------------------------- +# Expand IF-EMPTY if SET has no elements, otherwise IF-ELEMENTS. +m4_define([m4_set_empty], +[m4_ifdef([_m4_set_size($1)], + [m4_if(m4_indir([_m4_set_size($1)]), [0], [$2], [$3])], [$2])]) + +# m4_set_foreach(SET, VAR, ACTION) +# -------------------------------- +# For each element of SET, define VAR to the element and expand +# ACTION. ACTION should not recursively list SET's contents, add +# elements to SET, nor delete any element from SET except the one +# currently in VAR. The order that the elements are visited in is not +# guaranteed. This is faster than the corresponding m4_foreach([VAR], +# m4_indir([m4_dquote]m4_set_listc([SET])), [ACTION]) +m4_define([m4_set_foreach], +[m4_pushdef([$2])m4_set_map_sep([$1], [m4_define([$2],], [)$3])]) + +# m4_set_intersection(SET1, SET2) +# ------------------------------- +# Produce a LIST of quoted elements that occur in both SET1 or SET2. +# Output a comma prior to any elements, to distinguish the empty +# string from no elements. This can be directly used as a series of +# arguments, such as for m4_join, or wrapped inside quotes for use in +# m4_foreach. Order of the output is not guaranteed. +# +# Iterate over the smaller set, and short-circuit the idempotence +# relation. +m4_define([m4_set_intersection], +[m4_if([$1], [$2], [m4_set_listc([$1])], + m4_eval(m4_set_size([$2]) < m4_set_size([$1])), [1], [$0([$2], [$1])], + [m4_set_map_sep([$1], [_$0([$2],], [)])])]) + +m4_define([_m4_set_intersection], +[m4_set_contains([$1], [$2], [,[$2]])]) + +# m4_set_list(SET) +# m4_set_listc(SET) +# ----------------- +# Produce a LIST of quoted elements of SET. This can be directly used +# as a series of arguments, such as for m4_join or m4_set_add_all, or +# wrapped inside quotes for use in m4_foreach or m4_map. With +# m4_set_list, there is no way to distinguish an empty set from a set +# containing only the empty string; with m4_set_listc, a leading comma +# is output if there are any elements. +m4_define([m4_set_list], +[m4_set_map_sep([$1], [], [], [,])]) + +m4_define([m4_set_listc], +[m4_set_map_sep([$1], [,])]) + +# m4_set_map(SET, ACTION) +# ----------------------- +# For each element of SET, expand ACTION with a single argument of the +# current element. ACTION should not recursively list SET's contents, +# add elements to SET, nor delete any element from SET except the one +# passed as an argument. The order that the elements are visited in +# is not guaranteed. This is faster than either of the corresponding +# m4_map_args([ACTION]m4_set_listc([SET])) +# m4_set_foreach([SET], [VAR], [ACTION(m4_defn([VAR]))]) +m4_define([m4_set_map], +[m4_set_map_sep([$1], [$2(], [)])]) + +# m4_set_map_sep(SET, [PRE], [POST], [SEP]) +# ----------------------------------------- +# For each element of SET, expand PRE[value]POST[], and expand SEP +# between elements. +m4_define([m4_set_map_sep], +[m4_ifdef([_m4_set_cleanup($1)], [_m4_set_contents_1c], + [_m4_set_contents_1])([$1])_m4_set_contents_2($@)]) + +# m4_set_remove(SET, VALUE, [IF-PRESENT], [IF-ABSENT]) +# ---------------------------------------------------- +# If VALUE is an element of SET, delete it and expand IF-PRESENT. +# Otherwise expand IF-ABSENT. Deleting a single value is O(1), +# although it leaves memory occupied until the next O(n) traversal of +# the set which will compact the set. +# +# Optimize if the element being removed is the most recently added, +# since defining _m4_set_cleanup($1) slows down so many other macros. +# In particular, this plays well with m4_set_foreach and m4_set_map. +m4_define([m4_set_remove], +[m4_set_contains([$1], [$2], [_m4_set_size([$1], + [m4_decr])m4_if(_m4_defn([_m4_set([$1])]), [$2], + [_m4_popdef([_m4_set([$1],$2)], [_m4_set([$1])])], + [m4_define([_m4_set_cleanup($1)])m4_define( + [_m4_set([$1],$2)], [0])])$3], [$4])]) + +# m4_set_size(SET) +# ---------------- +# Expand to the number of elements currently in SET. This operation +# is O(1), and thus more efficient than m4_count(m4_set_list([SET])). +m4_define([m4_set_size], +[m4_ifdef([_m4_set_size($1)], [m4_indir([_m4_set_size($1)])], [0])]) + +# _m4_set_size(SET, ACTION) +# ------------------------- +# ACTION must be either m4_incr or m4_decr, and the size of SET is +# changed accordingly. If the set is empty, ACTION must not be +# m4_decr. +m4_define([_m4_set_size], +[m4_define([_m4_set_size($1)], + m4_ifdef([_m4_set_size($1)], [$2(m4_indir([_m4_set_size($1)]))], + [1]))]) + +# m4_set_union(SET1, SET2) +# ------------------------ +# Produce a LIST of double quoted elements that occur in either SET1 +# or SET2, without duplicates. Output a comma prior to any elements, +# to distinguish the empty string from no elements. This can be +# directly used as a series of arguments, such as for m4_join, or +# wrapped inside quotes for use in m4_foreach. Order of the output is +# not guaranteed. +# +# We can rely on the fact that m4_set_listc prunes SET1, so we don't +# need to check _m4_set([$1],element) for 0. Short-circuit the +# idempotence relation. +m4_define([m4_set_union], +[m4_set_listc([$1])m4_if([$1], [$2], [], + [m4_set_map_sep([$2], [_$0([$1],], [)])])]) + +m4_define([_m4_set_union], +[m4_ifdef([_m4_set([$1],$2)], [], [,[$2]])]) + + +## ------------------- ## +## 16. 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 than 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: $1])])]) + + + +## ------------------------ ## +## 17. Setting M4sugar up. ## +## ------------------------ ## + +# _m4_divert_diversion should be defined. +m4_divert_push([KILL]) + +# m4_init +# ------- +# Initialize the m4sugar language. +m4_define([m4_init], +[# All the M4sugar macros start with `m4_', except `dnl' kept as is +# for sake of simplicity. +m4_pattern_forbid([^_?m4_]) +m4_pattern_forbid([^dnl$]) + +# If __m4_version__ is defined, we assume that we are being run by M4 +# 1.6 or newer, thus $@ recursion is linear, and debugmode(+do) +# is available for faster checks of dereferencing undefined macros +# and forcing dumpdef to print to stderr regardless of debugfile. +# But if it is missing, we assume we are being run by M4 1.4.x, that +# $@ recursion is quadratic, and that we need foreach-based +# replacement macros. Also, m4 prior to 1.4.8 loses track of location +# during m4wrap text; __line__ should never be 0. +# +# Use the raw builtin to avoid tripping up include tracing. +# Meanwhile, avoid m4_copy, since it temporarily undefines m4_defn. +m4_ifdef([__m4_version__], +[m4_debugmode([+do]) +m4_define([m4_defn], _m4_defn([_m4_defn])) +m4_define([m4_dumpdef], _m4_defn([_m4_dumpdef])) +m4_define([m4_popdef], _m4_defn([_m4_popdef])) +m4_define([m4_undefine], _m4_defn([_m4_undefine]))], +[m4_builtin([include], [m4sugar/foreach.m4]) +m4_wrap_lifo([m4_if(__line__, [0], [m4_pushdef([m4_location], +]]m4_dquote(m4_dquote(m4_dquote(__file__:__line__)))[[)])])]) + +# Rewrite the first entry of the diversion stack. +m4_divert([KILL]) + +# Check the divert push/pop perfect balance. +# Some users are prone to also use m4_wrap to register last-minute +# m4_divert_text; so after our diversion cleanups, we restore +# KILL as the bottom of the diversion stack. +m4_wrap([m4_popdef([_m4_divert_diversion])m4_ifdef( + [_m4_divert_diversion], [m4_fatal([$0: unbalanced m4_divert_push: +]m4_divert_stack)])_m4_popdef([_m4_divert_stack])m4_divert_push([KILL])]) +]) |