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Diffstat (limited to 'gnuwin32/share/bison/m4sugar/m4sugar.m4')
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diff --git a/gnuwin32/share/bison/m4sugar/m4sugar.m4 b/gnuwin32/share/bison/m4sugar/m4sugar.m4 new file mode 100644 index 00000000..6fbd3431 --- /dev/null +++ b/gnuwin32/share/bison/m4sugar/m4sugar.m4 @@ -0,0 +1,2789 @@ +divert(-1)# -*- Autoconf -*- +# This file is part of Autoconf. +# Base M4 layer. +# Requires GNU M4. +# +# Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, +# 2008 Free Software Foundation, Inc. +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 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. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +# As a special exception, the Free Software Foundation gives unlimited +# permission to copy, distribute and modify the configure scripts that +# are the output of Autoconf. You need not follow the terms of the GNU +# General Public License when using or distributing such scripts, even +# though portions of the text of Autoconf appear in them. The GNU +# General Public License (GPL) does govern all other use of the material +# that constitutes the Autoconf program. +# +# Certain portions of the Autoconf source text are designed to be copied +# (in certain cases, depending on the input) into the output of +# Autoconf. We call these the "data" portions. The rest of the Autoconf +# source text consists of comments plus executable code that decides which +# of the data portions to output in any given case. We call these +# comments and executable code the "non-data" portions. Autoconf never +# copies any of the non-data portions into its output. +# +# This special exception to the GPL applies to versions of Autoconf +# released by the Free Software Foundation. When you make and +# distribute a modified version of Autoconf, you may extend this special +# exception to the GPL to apply to your modified version as well, *unless* +# your modified version has the potential to copy into its output some +# of the text that was the non-data portion of the version that you started +# with. (In other words, unless your change moves or copies text from +# the non-data portions to the data portions.) If your modification has +# such potential, you must delete any notice of this special exception +# to the GPL from your modified version. +# +# Written by Akim Demaille. +# + +# Set the quotes, whatever the current quoting system. +changequote() +changequote([, ]) + +# Some old m4's don't support m4exit. But they provide +# equivalent functionality by core dumping because of the +# long macros we define. +ifdef([__gnu__], , +[errprint(M4sugar requires GNU M4. Install it before installing M4sugar or +set the M4 environment variable to its 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'. +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_undefine([divert]) +m4_rename_m4([divnum]) +m4_rename_m4([dumpdef]) +m4_rename_m4([errprint]) +m4_rename_m4([esyscmd]) +m4_rename_m4([eval]) +m4_rename_m4([format]) +m4_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_undefine([undivert]) + + +## ------------------- ## +## 2. Error messages. ## +## ------------------- ## + + +# m4_location +# ----------- +m4_define([m4_location], +[__file__:__line__]) + + +# m4_errprintn(MSG) +# ----------------- +# Same as `errprint', but with the missing end of line. +m4_define([m4_errprintn], +[m4_errprint([$1 +])]) + + +# m4_warning(MSG) +# --------------- +# Warn the user. +m4_define([m4_warning], +[m4_errprintn(m4_location[: warning: $1])]) + + +# m4_fatal(MSG, [EXIT-STATUS]) +# ---------------------------- +# Fatal the user. :) +m4_define([m4_fatal], +[m4_errprintn(m4_location[: error: $1])dnl +m4_expansion_stack_dump()dnl +m4_exit(m4_if([$2],, 1, [$2]))]) + + +# m4_assert(EXPRESSION, [EXIT-STATUS = 1]) +# ---------------------------------------- +# This macro ensures that EXPRESSION evaluates to true, and exits if +# EXPRESSION evaluates to false. +m4_define([m4_assert], +[m4_if(m4_eval([$1]), 0, + [m4_fatal([assert failed: $1], [$2])])]) + + + +## ------------- ## +## 3. Warnings. ## +## ------------- ## + + +# _m4_warn(CATEGORY, MESSAGE, STACK-TRACE) +# ---------------------------------------- +# Report a MESSAGE to the user if the CATEGORY of warnings is enabled. +# This is for traces only. +# The STACK-TRACE is a \n-separated list of "LOCATION: MESSAGE". +# +# 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_defn([m4_expansion_stack]) +m4_location[: the top level]]))dnl +]) + + + +## ------------------- ## +## 4. File inclusion. ## +## ------------------- ## + + +# We also want to neutralize include (and sinclude for symmetry), +# but we want to extend them slightly: warn when a file is included +# several times. This is, in general, a dangerous operation, because +# 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_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_car(LIST) +# m4_cdr(LIST) +# ------------ +# Manipulate m4 lists. +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($@))])]) + +# _m4_cdr(LIST) +# ------------- +# Like m4_cdr, except include a leading comma unless only one element +# remains. Why? Because comparing a large list against [] is more +# expensive in expansion time than comparing the number of arguments; so +# _m4_cdr can be used to reduce the number of arguments when it is time +# to end recursion. +m4_define([_m4_cdr], +[m4_if([$#], 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_define_default(MACRO, VALUE) +# ------------------------------- +# If MACRO is undefined, set it to VALUE. +m4_define([m4_define_default], +[m4_ifndef([$1], [m4_define($@)])]) + + +# m4_default(EXP1, EXP2) +# ---------------------- +# Returns EXP1 if non empty, otherwise EXP2. +# +# This macro 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], [$1])]) + + +# m4_defn(NAME) +# ------------- +# Like the original, except guarantee a warning when using something which is +# undefined (unlike M4 1.4.x). This replacement is not a full-featured +# replacement: if any of the defined macros contain unbalanced quoting, but +# when pasted together result in a well-quoted string, then only native m4 +# support is able to get it correct. But that's where quadrigraphs come in +# handy, if you really need unbalanced quotes inside your macros. +# +# This macro is called frequently, so minimize the amount of additional +# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, +# (added in M4 1.6), then let m4 do the job for us (see m4_init). +# +# _m4_defn is for internal use only - it bypasses the wrapper, so it +# must only be used on one argument at a time, and only on macros +# known to be defined. Make sure this still works if the user renames +# m4_defn but not _m4_defn. +m4_copy([m4_defn], [_m4_defn]) +m4_define([m4_defn], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_defn([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_foreach([_m4_macro], [$@], [$0(_m4_defn([_m4_macro]))])])]) + + +# _m4_dumpdefs_up(NAME) +# --------------------- +m4_define([_m4_dumpdefs_up], +[m4_ifdef([$1], + [m4_pushdef([_m4_dumpdefs], _m4_defn([$1]))dnl +m4_dumpdef([$1])dnl +_m4_popdef([$1])dnl +_m4_dumpdefs_up([$1])])]) + + +# _m4_dumpdefs_down(NAME) +# ----------------------- +m4_define([_m4_dumpdefs_down], +[m4_ifdef([_m4_dumpdefs], + [m4_pushdef([$1], _m4_defn([_m4_dumpdefs]))dnl +_m4_popdef([_m4_dumpdefs])dnl +_m4_dumpdefs_down([$1])])]) + + +# m4_dumpdefs(NAME) +# ----------------- +# Similar to `m4_dumpdef(NAME)', but if NAME was m4_pushdef'ed, display its +# value stack (most recent displayed first). +m4_define([m4_dumpdefs], +[_m4_dumpdefs_up([$1])dnl +_m4_dumpdefs_down([$1])]) + + +# m4_popdef(NAME) +# --------------- +# Like the original, except guarantee a warning when using something which is +# undefined (unlike M4 1.4.x). +# +# This macro is called frequently, so minimize the amount of additional +# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists, +# (added in M4 1.6), then let m4 do the job for us (see m4_init). +# +# _m4_popdef is for internal use only - it bypasses the wrapper, so it +# must only be used on macros known to be defined. Make sure this +# still works if the user renames m4_popdef but not _m4_popdef. +m4_copy([m4_popdef], [_m4_popdef]) +m4_define([m4_popdef], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_popdef([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_foreach([_m4_macro], [$@], [$0(_m4_defn([_m4_macro]))])])]) + + +# 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_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_define([m4_undefine], +[m4_if([$#], [0], [[$0]], + [$#], [1], [m4_ifdef([$1], [_m4_undefine([$1])], + [m4_fatal([$0: undefined macro: $1])])], + [m4_foreach([_m4_macro], [$@], [$0(_m4_defn([_m4_macro]))])])]) + +# _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_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) +# -------------- +# Return the expansion of ARG as a single string. Unlike m4_quote($1), this +# correctly preserves whitespace following single-quoted commas that appeared +# within ARG. +# +# 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). The input +# is not likely to have unbalanced -=<{(/)}>=- quotes, and it is possible +# to have unbalanced (), provided it was specified with proper [] quotes. +# +# Exploit that extra () will group unquoted commas and the following +# whitespace, then convert () to []. m4_bpatsubst can't handle newlines +# inside $1, and m4_substr strips quoting. So we (ab)use m4_changequote. +m4_define([m4_expand], [_$0(-=<{($1)}>=-)]) +m4_define([_m4_expand], +[m4_changequote([-=<{(], [)}>=-])$1m4_changequote([, ])]) + + +# m4_ignore(ARGS) +# --------------- +# Expands to nothing. Useful for conditionally ignoring an arbitrary +# number of arguments (see _m4_list_cmp for an example). +m4_define([m4_ignore]) + + +# m4_make_list(ARGS) +# ------------------ +# Similar to m4_dquote, this creates a quoted list of quoted ARGS. This +# version is less efficient than m4_dquote, but separates each argument +# with a comma and newline, rather than just comma, for readability. +# When developing an m4sugar algorithm, you could temporarily use +# m4_pushdef([m4_dquote],m4_defn([m4_make_list])) +# around your code to make debugging easier. +m4_define([m4_make_list], [m4_join([, +], m4_dquote_elt($@))]) + + +# m4_noquote(STRING) +# ------------------ +# Return the result of ignoring all quotes in STRING and invoking the +# macros it contains. Amongst 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. +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([$4], + 1)))m4_assert(_m4_step > 0)_$0([$1], _m4_defn([$1]), + m4_eval((([$3]) - ([$2])) / _m4_step * _m4_step + ([$2])), + _m4_step, [$5])], + [m4_eval(([$3]) < ([$2]))], 1, + [m4_pushdef([_m4_step], m4_eval(m4_default([$4], + -1)))m4_assert(_m4_step < 0)_$0([$1], _m4_defn([$1]), + m4_eval((([$2]) - ([$3])) / -(_m4_step) * _m4_step + ([$2])), + _m4_step, [$5])], + [m4_pushdef([_m4_step])$5])[]]dnl +[m4_popdef([_m4_step], [$1])]) + + +# _m4_for(VARIABLE, COUNT, LAST, STEP, EXPRESSION) +# ------------------------------------------------ +# Core of the loop, no consistency checks, all arguments are plain +# numbers. Define VARIABLE to COUNT, expand EXPRESSION, then alter +# COUNT by STEP and iterate if COUNT is not LAST. +m4_define([_m4_for], +[m4_define([$1], [$2])$5[]m4_if([$2], [$3], [], + [$0([$1], m4_eval([$2 + $4]), [$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. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_foreach], +[m4_if([$2], [], [], + [m4_pushdef([$1])_$0([$1], [$3], [], $2)m4_popdef([$1])])]) + +m4_define([_m4_foreach], +[m4_if([$#], [3], [], + [m4_define([$1], [$4])$2[]$0([$1], [$2], m4_shift3($@))])]) + + +# m4_foreach_w(VARIABLE, LIST, EXPRESSION) +# ---------------------------------------- +# +# Like m4_foreach, but the list is whitespace separated. +# +# This macro is robust to active symbols: +# m4_foreach_w([Var], [ active +# b act\ +# ive ], [-Var-])end +# => -active--b--active-end +# +m4_define([m4_foreach_w], +[m4_foreach([$1], m4_split(m4_normalize([$2]), [ ]), [$3])]) + + +# 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, ignore the second argument, and use m4_shift2 to +# detect the end of recursion. The mismatch in () is intentional; see +# _m4_map. For m4_map, an empty list behaves like an empty sublist +# and gets ignored; for m4_mapall, we must special-case the empty +# list. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_map], +[_m4_map([_m4_apply([$1]], [], $2)]) + +m4_define([m4_mapall], +[m4_if([$2], [], [], + [_m4_map([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_map([_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_map([m4_apply([$2[]$1]], m4_shift2($@))]) + +# _m4_map(PREFIX, IGNORED, SUBLIST, ...) +# -------------------------------------- +# Common implementation for all four m4_map variants. The mismatch in +# the number of () is intentional. PREFIX must supply a form of +# m4_apply, the open `(', and the MACRO to be applied. Each iteration +# then appends `,', the current SUBLIST and the closing `)', then +# recurses to the next SUBLIST. IGNORED is an aid to ending recursion +# efficiently. +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([_m4_map], +[m4_if([$#], [2], [], + [$1, [$3])$0([$1], m4_shift2($@))])]) + +# m4_transform(EXPRESSION, ARG...) +# -------------------------------- +# Expand EXPRESSION([ARG]) for each argument. More efficient than +# m4_foreach([var], [ARG...], [EXPRESSION(m4_defn([var]))]) +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_transform], +[m4_if([$#], [0], [m4_fatal([$0: too few arguments: $#])], + [$#], [1], [], + [$#], [2], [$1([$2])[]], + [$1([$2])[]$0([$1], m4_shift2($@))])]) + + +# m4_transform_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], [($*)m4_newline])dnl +# m4_transform_pair([show], [], [a], [b], [c], [d], [e])dnl +# => (a,b) +# => (c,d) +# => (e) +# +# Please keep foreach.m4 in sync with any adjustments made here. +m4_define([m4_transform_pair], +[m4_if([$#], [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], [$2], m4_shift(m4_shift3($@)))])]) + + +## --------------------------- ## +## 9. More diversion support. ## +## --------------------------- ## + + +# _m4_divert(DIVERSION-NAME or NUMBER) +# ------------------------------------ +# If DIVERSION-NAME is the name of a diversion, return its number, +# otherwise if it is a NUMBER return it. +m4_define([_m4_divert], +[m4_ifdef([_m4_divert($1)], + [m4_indir([_m4_divert($1)])], + [$1])]) + +# KILL is only used to suppress output. +m4_define([_m4_divert(KILL)], -1) + +# The empty diversion name is a synonym for 0. +m4_define([_m4_divert()], 0) + + +# _m4_divert_n_stack +# ------------------ +# Print m4_divert_stack with newline prepended, if it's nonempty. +m4_define([_m4_divert_n_stack], +[m4_ifdef([m4_divert_stack], [ +_m4_defn([m4_divert_stack])])]) + + +# m4_divert(DIVERSION-NAME) +# ------------------------- +# Change the diversion stream to DIVERSION-NAME. +m4_define([m4_divert], +[m4_define([m4_divert_stack], m4_location[: $0: $1]_m4_divert_n_stack)]dnl +[m4_builtin([divert], _m4_divert([$1]))]) + + +# m4_divert_push(DIVERSION-NAME) +# ------------------------------ +# Change the diversion stream to DIVERSION-NAME, while stacking old values. +m4_define([m4_divert_push], +[m4_pushdef([m4_divert_stack], m4_location[: $0: $1]_m4_divert_n_stack)]dnl +[m4_pushdef([_m4_divert_diversion], [$1])]dnl +[m4_builtin([divert], _m4_divert([$1]))]) + + +# 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_ifndef([_m4_divert_diversion], + [m4_fatal([too many m4_divert_pop])])]dnl +[m4_if([$1], [], [], + [$1], _m4_defn([_m4_divert_diversion]), [], + [m4_fatal([$0($1): diversion mismatch: ]_m4_divert_n_stack)])]dnl +[_m4_popdef([m4_divert_stack], [_m4_divert_diversion])]dnl +[m4_builtin([divert], + m4_ifdef([_m4_divert_diversion], + [_m4_divert(_m4_defn([_m4_divert_diversion]))], + -1))]) + + +# 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_undivert(DIVERSION-NAME) +# --------------------------- +# Undivert DIVERSION-NAME. Unlike the M4 version, this only takes a single +# diversion identifier, and should not be used to undivert files. +m4_define([m4_undivert], +[m4_builtin([undivert], _m4_divert([$1]))]) + + +## --------------------------------------------- ## +## 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 AC_PROVIDE's the macro, so that a macro which has +# been expanded is not expanded again when m4_require'd, but the +# difficult part is the proper expansion of macros when they are +# m4_require'd. +# +# The implementation is based on two ideas, (i) using diversions to +# prepare the expansion of the macro and its dependencies (by Franc,ois +# Pinard), and (ii) expand the most recently m4_require'd macros _after_ +# the previous macros (by Axel Thimm). +# +# +# The first idea: why 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...REQUIRE([TEST2])1]) +# | m4_defun([TEST2], [Test...REQUIRE([TEST3])2]) +# | m4_defun([TEST3], [Test...3]) +# +# Because m4_require is not required to be first in the outer macros, we +# must keep the expansions of the various 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], [REQUIRE([TEST2a])REQUIRE([TEST2b])]) +# | m4_defun([TEST2a], []) +# | m4_defun([TEST2b], [REQUIRE([TEST3])]) +# | m4_defun([TEST3], [REQUIRE([TEST2a])]) +# | +# | AC_INIT +# | TEST1 +# +# The dependencies between the macros are: +# +# 3 --- 2b +# / \ is m4_require'd by +# / \ left -------------------- right +# 2a ------------ 1 +# +# If you strictly apply the rules given in the previous section you get: +# +# GROW - 2: TEST3 +# GROW - 1: TEST2a; TEST2b +# GROW: TEST1 +# BODY: +# +# (TEST2a, although required by TEST3 is not expanded in GROW - 3 +# because is has already been expanded before in GROW - 1, so it has +# been AC_PROVIDE'd, so it is not expanded again) so when you undivert +# the stack of diversions, you get: +# +# GROW - 2: +# GROW - 1: +# GROW: +# BODY: TEST3; TEST2a; TEST2b; TEST1 +# +# i.e., TEST2a is expanded after TEST3 although the latter required the +# former. +# +# Starting from 2.50, 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 AC_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 evolved. If you +# are like me, you will want to see the actual functioning of this +# implementation to be convinced. The next section gives the full +# details. +# +# +# The Axel Thimm implementation at work +# ------------------------------------- +# +# We consider the macros above, and this configure.ac: +# +# AC_INIT +# TEST1 +# +# You should keep the definitions of _m4_defun_pro, _m4_defun_epi, and +# m4_require at hand to follow the steps. +# +# This implements tries not to assume that 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 |- +# Than 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 |- +# Than 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 |- +# +# +# 2. Keeping track of the expansion stack +# ======================================= +# +# When M4 expansion goes wrong it is often extremely hard to find the +# path amongst macros that drove to the failure. What is needed is +# the stack of macro `calls'. One could imagine that GNU M4 would +# maintain a stack of macro expansions, unfortunately it doesn't, so +# we do it by hand. This is of course extremely costly, but the help +# this stack provides is worth it. Nevertheless to limit the +# performance penalty this is implemented only for m4_defun'd macros, +# not for define'd macros. +# +# The scheme is simplistic: each time we enter an m4_defun'd macros, +# we prepend its name in m4_expansion_stack, and when we exit the +# macro, we remove it (thanks to pushdef/popdef). +# +# In addition, we want to 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_push(TEXT) +# ----------------------------- +m4_define([m4_expansion_stack_push], +[m4_pushdef([m4_expansion_stack], + [$1]m4_ifdef([m4_expansion_stack], [ +_m4_defn([m4_expansion_stack])]))]) + + +# m4_expansion_stack_pop +# ---------------------- +m4_define([m4_expansion_stack_pop], +[m4_popdef([m4_expansion_stack])]) + + +# m4_expansion_stack_dump +# ----------------------- +# Dump the expansion stack. +m4_define([m4_expansion_stack_dump], +[m4_ifdef([m4_expansion_stack], + [m4_errprintn(_m4_defn([m4_expansion_stack]))])dnl +m4_errprintn(m4_location[: the top level])]) + + +# _m4_divert(GROW) +# ---------------- +# This diversion is used by the m4_defun/m4_require machinery. It is +# important to keep room before GROW because for each nested +# AC_REQUIRE we use an additional diversion (i.e., two m4_require's +# will use GROW - 2. More than 3 levels has never seemed to be +# needed.) +# +# ... +# - GROW - 2 +# m4_require'd code, 2 level deep +# - GROW - 1 +# m4_require'd code, 1 level deep +# - GROW +# m4_defun'd macros are elaborated here. + +m4_define([_m4_divert(GROW)], 10000) + + +# _m4_defun_pro(MACRO-NAME) +# ------------------------- +# The prologue for Autoconf macros. +# +# This is called frequently, so minimize the number of macro invocations +# by avoiding dnl and m4_defn overhead. +m4_define([_m4_defun_pro], +m4_do([[m4_ifdef([m4_expansion_stack], [], [_m4_defun_pro_outer[]])]], + [[m4_expansion_stack_push(_m4_defn( + [m4_location($1)])[: $1 is expanded from...])]], + [[m4_pushdef([_m4_expanding($1)])]])) + +m4_define([_m4_defun_pro_outer], +[m4_copy([_m4_divert_diversion], [_m4_divert_dump])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_do([[_m4_popdef([_m4_expanding($1)])]], + [[m4_expansion_stack_pop()]], + [[m4_ifdef([m4_expansion_stack], [], [_m4_defun_epi_outer[]])]], + [[m4_provide([$1])]])) + +m4_define([_m4_defun_epi_outer], +[_m4_undefine([_m4_divert_dump])m4_divert_pop([GROW])m4_undivert([GROW])]) + + +# m4_defun(NAME, EXPANSION) +# ------------------------- +# Define a macro which automatically provides itself. Add machinery +# so the macro automatically switches expansion to the diversion +# stack if it is not already using it. In this case, once finished, +# it will bring back all the code accumulated in the diversion stack. +# This, combined with m4_require, achieves the topological ordering of +# macros. We don't use this macro to define some frequently called +# macros that are not involved in ordering constraints, to save m4 +# processing. +m4_define([m4_defun], +[m4_define([m4_location($1)], m4_location)dnl +m4_define([$1], + [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])]) + + +# m4_defun_once(NAME, EXPANSION) +# ------------------------------ +# As m4_defun, but issues the EXPANSION only once, and warns if used +# several times. +m4_define([m4_defun_once], +[m4_define([m4_location($1)], m4_location)dnl +m4_define([$1], + [m4_provide_if([$1], + [m4_warn([syntax], [$1 invoked multiple times])], + [_m4_defun_pro([$1])$2[]_m4_defun_epi([$1])])])]) + + +# m4_pattern_forbid(ERE, [WHY]) +# ----------------------------- +# Declare that no token matching the 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. Once expanded, emit it in _m4_divert_dump. Keep track +# of the m4_require chain in m4_expansion_stack. +# +# The normal cases are: +# +# - NAME-TO-CHECK == BODY-TO-EXPAND +# Which you can use for regular macros with or without arguments, e.g., +# m4_require([AC_PROG_CC], [AC_PROG_CC]) +# m4_require([AC_CHECK_HEADERS(limits.h)], [AC_CHECK_HEADERS(limits.h)]) +# which is just the same as +# m4_require([AC_PROG_CC]) +# m4_require([AC_CHECK_HEADERS(limits.h)]) +# +# - BODY-TO-EXPAND == m4_indir([NAME-TO-CHECK]) +# In the case of macros with irregular names. For instance: +# m4_require([AC_LANG_COMPILER(C)], [indir([AC_LANG_COMPILER(C)])]) +# which means `if the macro named `AC_LANG_COMPILER(C)' (the parens are +# part of the name, it is not an argument) has not been run, then +# call it.' +# Had you used +# m4_require([AC_LANG_COMPILER(C)], [AC_LANG_COMPILER(C)]) +# then m4_require would have tried to expand `AC_LANG_COMPILER(C)', i.e., +# call the macro `AC_LANG_COMPILER' with `C' as argument. +# +# You could argue that `AC_LANG_COMPILER', when it receives an argument +# such as `C' should dispatch the call to `AC_LANG_COMPILER(C)'. But this +# `extension' prevents `AC_LANG_COMPILER' from having actual arguments that +# it passes to `AC_LANG_COMPILER(C)'. +# +# 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_do([[m4_ifdef([_m4_expanding($1)], + [m4_fatal([$0: circular dependency of $1])])]], + [[m4_ifdef([_m4_divert_dump], [], + [m4_fatal([$0($1): cannot be used outside of an ]dnl +m4_bmatch([$0], [^AC_], [[AC_DEFUN]], [[m4_defun]])['d macro])])]], + [[m4_provide_if([$1], + [], + [_m4_require_call([$1], [$2])])]])) + + +# _m4_require_call(NAME-TO-CHECK, [BODY-TO-EXPAND = NAME-TO-CHECK]) +# ----------------------------------------------------------------- +# If m4_require decides to expand the body, it calls this macro. +# +# 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_call], +m4_do([[m4_define([_m4_divert_grow], m4_decr(_m4_divert_grow))]], + [[m4_divert_push(_m4_divert_grow)]], + [[m4_default([$2], [$1]) +m4_provide_if([$1], + [], + [m4_warn([syntax], + [$1 is m4_require'd but not m4_defun'd])])]], + [[m4_divert(_m4_defn([_m4_divert_dump]))]], + [[m4_undivert(_m4_divert_grow)]], + [[m4_divert_pop(_m4_divert_grow)]], + [[m4_define([_m4_divert_grow], m4_incr(_m4_divert_grow))]])) + + +# _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_ifval([$2], [[$2]], [[$1]]), + [], + [m4_provide(m4_ifval([$2], [[$2]], [[$1]]))[]$1])]) + + +# m4_provide(MACRO-NAME) +# ---------------------- +m4_define([m4_provide], +[m4_define([m4_provide($1)])]) + + +# m4_provide_if(MACRO-NAME, IF-PROVIDED, IF-NOT-PROVIDED) +# ------------------------------------------------------- +# If MACRO-NAME is provided do IF-PROVIDED, else IF-NOT-PROVIDED. +# The purpose of this macro is to provide the user with a means to +# check macros which are provided without letting her know how the +# information is coded. +m4_define([m4_provide_if], +[m4_ifdef([m4_provide($1)], + [$2], [$3])]) + + +## --------------------- ## +## 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. +# +# 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 +# ---------- +# Expands to a newline. Exists for formatting reasons. +m4_define([m4_newline], [ +]) + + +# 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]]], [_$0($@)])], + [$2], [], [_$0([$1], [[ ]+])], + [_$0($@)])]) + +m4_define([_m4_split], +[m4_changequote([-=<{(],[)}>=-])]dnl +[[m4_bpatsubst(-=<{(-=<{($1)}>=-)}>=-, -=<{($2)}>=-, + -=<{(], [)}>=-)]m4_changequote([, ])]) + + + +# m4_flatten(STRING) +# ------------------ +# If STRING contains end of lines, replace them with spaces. If there +# are backslashed end of lines, remove them. This macro is safe with +# active symbols. +# m4_define(active, ACTIVE) +# m4_flatten([active +# act\ +# ive])end +# => active activeend +# +# 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 +# +# In order to have the correct number of SEPARATORs, we use a temporary +# variable that redefines itself after the first use. We must use defn +# rather than overquoting in case PREFIX or SUFFIX contains $1, but use +# _m4_defn for speed. Likewise, we compute the m4_shift3 only once, +# rather than in each iteration of the outer m4_foreach. +m4_define([m4_combine], +[m4_if(m4_eval([$# > 3]), [1], + [m4_pushdef([m4_Separator], [m4_define([m4_Separator], + _m4_defn([m4_echo]))])]]dnl +[[m4_foreach([m4_Prefix], [$2], + [m4_foreach([m4_Suffix], ]m4_dquote(m4_dquote(m4_shift3($@)))[, + [m4_Separator([$1])[]_m4_defn([m4_Prefix])[$3]_m4_defn( + [m4_Suffix])])])]]dnl +[[_m4_popdef([m4_Separator])])]) + + +# 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_foreach_w([m4_Word], [$2], + [_m4_append_uniq([$1], _m4_defn([m4_Word]), [ ])])]) + + +# 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. +# +# 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([$1], [$2], m4_if([$3], [], [[$2]], [[$3]]), + m4_if([$4], [], [79], [[$4]]))]) +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 curser 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_foreach_w([m4_Word], [$1], + [m4_define([m4_Cursor], + m4_eval(m4_Cursor + m4_qlen(_m4_defn([m4_Word])) + + 1))m4_if(m4_eval(m4_Cursor > ([$4])), + [1], [m4_define([m4_Cursor], + m4_eval(m4_Indent + m4_qlen(_m4_defn([m4_Word])) + 1)) +[$2]], + [m4_Separator[]])_m4_defn([m4_Word])])]], +dnl finally, clean up the local variabls +[[_m4_popdef([m4_Separator], [m4_Cursor], [m4_Indent])]])) + + +# m4_text_box(MESSAGE, [FRAME-CHARACTER = `-']) +# --------------------------------------------- +# Turn MESSAGE into: +# ## ------- ## +# ## MESSAGE ## +# ## ------- ## +# using FRAME-CHARACTER in the border. +m4_define([m4_text_box], +[m4_pushdef([m4_Border], + m4_translit(m4_format([%*s], m4_qlen(m4_expand([$1])), []), + [ ], m4_if([$2], [], [[-]], [[$2]])))dnl +@%:@@%:@ m4_Border @%:@@%:@ +@%:@@%:@ $1 @%:@@%:@ +@%:@@%:@ m4_Border @%:@@%:@_m4_popdef([m4_Border])dnl +]) + + +# m4_qlen(STRING) +# --------------- +# Expands to the length of STRING after autom4te converts all quadrigraphs. +# +# Avoid bpatsubsts for the common case of no quadrigraphs. +m4_define([m4_qlen], +[m4_if(m4_index([$1], [@]), [-1], [m4_len([$1])], + [m4_len(m4_bpatsubst([[$1]], + [@\(\(<:\|:>\|S|\|%:\|\{:\|:\}\)\(@\)\|&t@\)], + [\3]))])]) + + +# m4_qdelta(STRING) +# ----------------- +# Expands to the net change in the length of STRING from autom4te converting the +# quadrigraphs in STRING. This number is always negative or zero. +m4_define([m4_qdelta], +[m4_eval(m4_qlen([$1]) - m4_len([$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] -> [2.14+1.-1.[0r36:a]] -> 2.15.-1.10 +# [2.14b] -> [2.15+1.-1.[0r36:b]] -> 2.15.-1.11 +# [2.61aa.b] -> [2.61+1.-1.[0r36:aa],+1.-1.[0r36:b]] -> 2.62.-1.370.1.-1.11 +# +# 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] is less readable than 10, we provide a wrapper for +# human use. +m4_define([m4_version_unletter], +[m4_map_sep([m4_eval], [.], + m4_dquote(m4_dquote_elt(m4_unquote(_$0([$1])))))]) +m4_define([_m4_version_unletter], +[m4_bpatsubst(m4_translit([[[$1]]], [.-], [,,]),]dnl +m4_dquote(m4_dquote(m4_defn([m4_cr_Letters])))[[+], + [+1,-1,[0r36:\&]])]) + + +# 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_ifdef([_m4_set_cleanup($1)], [_$0_1c], [_$0_1])([$1])_$0_2([$1], + [_m4_defn([_m4_set_($1)])], [[$2]])]) + +# _m4_set_contents_1(SET) +# _m4_set_contents_1c(SET) +# _m4_set_contents_2(SET, SEP, PREP) +# ---------------------------------- +# Expand to a list of quoted elements currently in the set, separated +# by SEP, and moving PREP in front of SEP 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. SEP is expanded while +# _m4_set_($1) contains the current element, so a SEP containing +# _m4_defn([_m4_set_($1)]) can produce output in the order the set was +# created. Behavior is undefined if 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_ifdef([_m4_set([$1])], [m4_pushdef([_m4_set_($1)], + _m4_defn([_m4_set([$1])]))_m4_popdef([_m4_set([$1])])$0([$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_ifdef([_m4_set_($1)], [m4_pushdef([_m4_set([$1])], + _m4_defn([_m4_set_($1)]))$2[]_m4_popdef([_m4_set_($1)])$0([$1], [$3$2])])]) + +# 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. Use _m4_defn for speed. +m4_define([m4_set_difference], +[m4_if([$1], [$2], [], + [m4_set_foreach([$1], [_m4_element], + [m4_set_contains([$2], _m4_defn([_m4_element]), [], + [,_m4_defn([_m4_element])])])])]) + +# 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_ifdef([_m4_set_cleanup($1)], + [_m4_set_contents_1c], [_m4_set_contents_1])([$1])_m4_set_contents_2([$1], + [m4_define([$2], _m4_defn([_m4_set_($1)]))$3[]])m4_popdef([$2])]) + +# 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. Use _m4_defn for speed. +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_foreach([$1], [_m4_element], + [m4_set_contains([$2], _m4_defn([_m4_element]), + [,_m4_defn([_m4_element])])])])]) + +# 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_ifdef([_m4_set_cleanup($1)], [_m4_set_contents_1c], + [_m4_set_contents_1])([$1])_m4_set_contents_2([$1], + [_m4_defn([_m4_set_($1)])], [,])]) + +m4_define([m4_set_listc], +[m4_ifdef([_m4_set_cleanup($1)], [_m4_set_contents_1c], + [_m4_set_contents_1])([$1])_m4_set_contents_2([$1], + [,_m4_defn([_m4_set_($1)])])]) + +# 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. +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. Use _m4_defn for speed. +# Short-circuit the idempotence relation. +m4_define([m4_set_union], +[m4_set_listc([$1])m4_if([$1], [$2], [], [m4_set_foreach([$2], [_m4_element], + [m4_ifdef([_m4_set([$1],]_m4_defn([_m4_element])[)], [], + [,_m4_defn([_m4_element])])])])]) + + +## ------------------- ## +## 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: $1])])]) + + + +## ------------------------ ## +## 17. Setting M4sugar up. ## +## ------------------------ ## + + +# m4_init +# ------- +# Initialize the m4sugar language. +m4_define([m4_init], +[# All the M4sugar macros start with `m4_', except `dnl' kept as is +# for sake of simplicity. +m4_pattern_forbid([^_?m4_]) +m4_pattern_forbid([^dnl$]) + +# If __m4_version__ is defined, we assume that we are being run by M4 +# 1.6 or newer, and thus that $@ recursion is linear and debugmode(d) +# is available for faster checks of dereferencing undefined macros. +# 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. Use the raw builtin to avoid tripping up +# include tracing. +m4_ifdef([__m4_version__], +[m4_debugmode([+d]) +m4_copy([_m4_defn], [m4_defn]) +m4_copy([_m4_popdef], [m4_popdef]) +m4_copy([_m4_undefine], [m4_undefine])], +[m4_builtin([include], [m4sugar/foreach.m4])]) + +# _m4_divert_diversion should be defined: +m4_divert_push([KILL]) + +# Check the divert push/pop perfect balance. +m4_wrap([m4_divert_pop([]) + m4_ifdef([_m4_divert_diversion], + [m4_fatal([$0: unbalanced m4_divert_push:]_m4_divert_n_stack)])[]]) +]) |