# This file is part of Autoconf. -*- Autoconf -*-
# Driver that loads the Autoconf macro files.
#
-# Copyright (C) 1994, 1999, 2000, 2001, 2002, 2006 Free Software
+# Copyright (C) 1994, 1999, 2000, 2001, 2002, 2006, 2008 Free Software
# Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# names too. But users may still depend upon these, so reestablish
# them.
+# In order to copy pushdef stacks, m4_copy temporarily destroys the
+# current pushdef stack. But these builtins are so primitive that:
+# 1. they should not have more than one pushdef definition
+# 2. undefining the pushdef stack to copy breaks m4_copy
+# Hence, we temporarily restore a simpler m4_copy.
+
+m4_pushdef([m4_copy], [m4_define([$2], m4_defn([$1]))])
+
m4_copy_unm4([m4_builtin])
m4_copy_unm4([m4_changequote])
m4_copy_unm4([m4_decr])
m4_copy_unm4([m4_undefine])
m4_copy_unm4([m4_undivert])
+m4_popdef([m4_copy])
+
# Yet some people have started to use m4_patsubst and m4_regexp.
m4_define([m4_patsubst],
[m4_expand_once([m4_warn([syntax],
# Nevertheless, one huge difference is the handling of `$0'. If `from'
# uses `$0', then with 1, `to''s `$0' is `to', while it is `from' in 2.
# The user would certainly prefer to see `to'.
+#
+# This definition is in effect during m4sugar initialization, when
+# there are no pushdef stacks; later on, we redefine it to something
+# more powerful for all other clients to use.
m4_define([m4_copy],
[m4_define([$2], m4_defn([$1]))])
m4_rename_m4([translit])
m4_undefine([undivert])
+# _m4_defn(ARG)
+# ----------------
+# _m4_defn is for internal use only - it bypasses the wrapper, so it
+# must only be used on one argument at a time, and only on macros
+# known to be defined. Make sure this still works if the user renames
+# m4_defn but not _m4_defn.
+m4_copy([m4_defn], [_m4_defn])
+
+# _m4_popdef(ARG...)
+# ------------------
+# _m4_popdef is for internal use only - it bypasses the wrapper, so it
+# must only be used on macros known to be defined. Make sure this
+# still works if the user renames m4_popdef but not _m4_popdef.
+m4_copy([m4_popdef], [_m4_popdef])
+
+# _m4_undefine(ARG...)
+# --------------------
+# _m4_undefine is for internal use only - it bypasses the wrapper, so
+# it must only be used on macros known to be defined. Make sure this
+# still works if the user renames m4_undefine but not _m4_undefine.
+m4_copy([m4_undefine], [_m4_undefine])
+
## ------------------- ##
## 2. Error messages. ##
m4_shift3($@))])])
+# m4_copy(SRC, DST)
+# -----------------
+# Define the pushdef stack DST as a copy of the pushdef stack SRC;
+# give an error if DST is already defined. This is particularly nice
+# for copying self-modifying pushdef stacks, where the top definition
+# includes one-shot initialization that is later popped to the normal
+# definition.
+#
+# The recursive worker destructively swaps the order of a stack. We
+# use a temporary stack, and swap directions twice, using the third
+# argument to restore the original stack.
+#
+# Some macros simply can't be renamed with this method: namely,
+# anything involved in the implementation of _m4_copy.
+m4_define([m4_copy],
+[m4_ifdef([$2], [m4_fatal([$0: won't overwrite defined macro: $2])],
+ [_$0([$1], [m4_tmp])_$0([m4_tmp], [$2],
+ [m4_pushdef([$1], _m4_defn([m4_tmp]))])])])
+m4_define([_m4_copy],
+[m4_ifdef([$1], [m4_pushdef([$2], _m4_defn([$1]))$3[]_m4_popdef([$1])$0($@)])])
+
+
# m4_define_default(MACRO, VALUE)
# -------------------------------
# If MACRO is undefined, set it to VALUE.
# 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([$1])],
# This macro is called frequently, so minimize the amount of additional
# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists,
# (added in M4 1.6), then let m4 do the job for us (see m4_init).
-#
-# _m4_popdef is for internal use only - it bypasses the wrapper, so it
-# must only be used on macros known to be defined. Make sure this
-# still works if the user renames m4_popdef but not _m4_popdef.
-m4_copy([m4_popdef], [_m4_popdef])
m4_define([m4_popdef],
[m4_if([$#], [0], [[$0]],
[$#], [1], [m4_ifdef([$1], [_m4_popdef([$1])],
# This macro is called frequently, so minimize the amount of additional
# expansions by skipping m4_ifndef. Better yet, if __m4_version__ exists,
# (added in M4 1.6), then let m4 do the job for us (see m4_init).
-#
-# _m4_undefine is for internal use only - it bypasses the wrapper, so
-# it must only be used on macros known to be defined. Make sure this
-# still works if the user renames m4_undefine but not _m4_undefine.
-m4_copy([m4_undefine], [_m4_undefine])
m4_define([m4_undefine],
[m4_if([$#], [0], [[$0]],
[$#], [1], [m4_ifdef([$1], [_m4_undefine([$1])],
[[m4_pushdef([_m4_expanding($1)])]]))
m4_define([_m4_defun_pro_outer],
-[m4_copy([_m4_divert_diversion], [_m4_divert_dump])m4_divert_push([GROW])])
+[m4_define([_m4_divert_dump],
+ m4_defn([_m4_divert_diversion]))m4_divert_push([GROW])])
# _m4_defun_epi(MACRO-NAME)
# -------------------------
# 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.
+# include tracing. Meanwhile, avoid m4_copy, since it temporarily
+# undefines m4_defn.
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_define([m4_defn], _m4_defn([m4_defn]))
+m4_define([m4_popdef], _m4_defn([m4_popdef]))
+m4_define([m4_undefine], _m4_defn([m4_undefine]))],
[m4_builtin([include], [m4sugar/foreach.m4])])
# _m4_divert_diversion should be defined:
projects / thirdparty / autoconf.git / commitdiff
