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The current implementation of AC_REQUIRE fails on
| AC_DEFUN([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])]) | AC_DEFUN([TEST2a], []) | AC_DEFUN([TEST2b], [REQUIRE([TEST3])]) | AC_DEFUN([TEST3], [REQUIRE([TEST2a])]) | | AC_INIT | TEST1 because it produces TEST3; TEST2a; TEST2b; TEST1. Fix this bug, implement the solution provided by Axel Thimm, and test AC_REQUIRE. * acgeneral.m4: Document this implementation. (_AC_DEFUN_PRO, _AC_DEFUN_EPI, AC_REQUIRE): Be sure that macros are emitted in the same order as they are expanded. (AC_REQUIRE): Forbid being calling out of an AC_DEFUN'd macro (in particular the top level). * tests/base.m4 (AC_REQUIRE): New test.
This commit is contained in:
Akim Demaille
parent
439ddf9140
commit
12e3a8ea6e
23
ChangeLog
23
ChangeLog
@ -1,3 +1,26 @@
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2000-06-26 Akim Demaille <akim@epita.fr>
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The current implementation of AC_REQUIRE fails on
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| AC_DEFUN([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])])
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| AC_DEFUN([TEST2a], [])
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| AC_DEFUN([TEST2b], [REQUIRE([TEST3])])
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| AC_DEFUN([TEST3], [REQUIRE([TEST2a])])
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|
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| AC_INIT
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| TEST1
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because it produces TEST3; TEST2a; TEST2b; TEST1.
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Fix this bug, implement the solution provided by Axel Thimm,
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and test AC_REQUIRE.
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* acgeneral.m4: Document this implementation.
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(_AC_DEFUN_PRO, _AC_DEFUN_EPI, AC_REQUIRE): Be sure that macros
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are emitted in the same order as they are expanded.
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(AC_REQUIRE): Forbid being calling out of an AC_DEFUN'd macro (in
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particular the top level).
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* tests/base.m4 (AC_REQUIRE): New test.
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2000-06-26 Akim Demaille <akim@epita.fr>
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A macro which is not defined with AC_DEFUN should not be
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3
NEWS
3
NEWS
@ -95,6 +95,9 @@ test cases in this new frame work.
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Most macros, if not all, now strictly follow the `one quotation
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level' rule. This results in a more predictable expansion.
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- AC_REQUIRE
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A sly bug in the AC_REQUIRE machinery, which could produce incorrect
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configure scripts, was fixed by Axel Thimm.
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** Setup Macros
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- AC_ARG_VAR
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3
THANKS
3
THANKS
@ -11,7 +11,8 @@ Alexandre Oliva oliva@lsd.ic.unicamp.br
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Andreas Schott schott@rzg.mpg.de
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Andreas Schwab schwab@issan.informatik.uni-dortmund.de
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Andrej Borsenkow borsenkow.msk@sni.de
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Ben Elliston bje@cygnus.com
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Axel Thimm ifh.de
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Ben Elliston bje@redhat.com
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Bill Sommerfeld sommerfeld@apollo.hp.com
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Bob Friesenhahn bfriesen@simple.dallas.tx.us
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Bruno Haible haible@ilog.fr
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314
acgeneral.m4
314
acgeneral.m4
@ -187,15 +187,301 @@ pushdef([AC_DIVERT_DIVERSION], _AC_DIVERT([KILL]))
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## Defining macros in autoconf::. ##
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## ------------------------------- ##
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# `AC_DEFUN' is basically `define' but it equips the macro with the
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# needed machinery for `AC_REQUIRE'. A macro must be AC_DEFUN'd if
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# either it is AC_REQUIRE'd, or it AC_REQUIRE's.
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#
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# Of course AC_DEFUN AC_PROVIDE's the macro, so that a macro which has
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# been expanded is not expanded again when AC_REQUIRE'd, but the
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# difficult part is the proper expansion of macros when they are
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# AC_REQUIRE'd.
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#
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# The implementation is based on two ideas, (i) using diversions to
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# prepare the expansion of the macro and its dependencies (by François
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# Pinard), and (ii) expand the most recently AC_REQUIRE'd macros _after_
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# the previous macros (by Axel Thimm).
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#
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#
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# The first idea: why using diversions?
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# -------------------------------------
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#
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# When a macro requires another, the other macro is expanded in new
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# diversion, NORMAL_1. When the outer macro is fully expanded, we first
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# undivert the most nested diversions (NORMAL_2...), and finally
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# undivert NORMAL_1. To understand why we need several diversions,
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# consider the following example:
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#
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# | AC_DEFUN([TEST1], [Test...REQUIRE([TEST2])1])
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# | AC_DEFUN([TEST2], [Test...REQUIRE([TEST3])2])
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# | AC_DEFUN([TEST3], [Test...3])
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#
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# Because AC_REQUIRE is not required to be first in the outer macros, we
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# must keep the expansions of the various level of AC_REQUIRE separated.
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# Right before executing the epilogue of TEST1, we have:
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#
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# NORMAL_3: Test...3
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# NORMAL_1: Test...2
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# NORMAL_1: Test...1
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# NORMAL:
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#
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# Finally the epilogue of TEST1 undiverts NORMAL_3, 2, and 1 into the
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# regular flow, NORMAL.
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#
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# NORMAL_3:
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# NORMAL_1:
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# NORMAL_1:
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# NORMAL: Test...3; Test...2; Test...1
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#
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# (The semicolons are here for clarification, but of course are not
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# emitted.) This is what Autoconf 2.0 (I think) to 2.13 (I'm sure)
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# implement.
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#
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#
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# The second idea: first required first out
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# -----------------------------------------
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#
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# The natural implementation of the idea above is buggy and produces
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# very surprising results in some situations. Let's consider the
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# following example to explain the bug:
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#
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# | AC_DEFUN([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])])
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# | AC_DEFUN([TEST2a], [])
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# | AC_DEFUN([TEST2b], [REQUIRE([TEST3])])
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# | AC_DEFUN([TEST3], [REQUIRE([TEST2a])])
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# |
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# | AC_INIT
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# | TEST1
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#
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# The dependencies between the macros are:
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#
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# 3 --- 2b
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# / \ is AC_REQUIRE'd by
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# / \ left -------------------- right
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# 2a ------------ 1
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#
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# If you strictly apply the rules given in the previous section you get:
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#
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# NORMAL_3: TEST3
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# NORMAL_2: TEST2a; TEST2b
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# NORMAL_1: TEST1
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# NORMAL:
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#
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# (TEST2a, although required by TEST3 is not expanded in NORMAL_4
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# because is has already been expanded before in NORMAL_2, so it has
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# been AC_PROVIDE'd, so it is not expanded again) so when you undivert
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# the stack of diversions, you get:
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#
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# NORMAL_3:
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# NORMAL_2:
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# NORMAL_1:
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# NORMAL: TEST3; TEST2a; TEST2b; TEST1
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#
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# i.e., TEST2a is expanded after TEST3 although the latter required the
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# former.
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#
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# Starting from 2.50, uses an implementation provided by Axel Thimm.
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# The idea is simple: the order in which macros are emitted must be the
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# same as the one in which macro are expanded. (The bug above can
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# indeed be described as: a macro has been AC_PROVIDE'd, but it is
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# emitted after: the lack of correlation between emission and expansion
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# order is guilty).
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#
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# How to do that? You keeping the stack of diversions to elaborate the
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# macros, but each time a macro is fully expanded, emit it immediately.
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#
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# In the example above, when TEST2a is expanded, but it's epilogue is
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# not run yet, you have:
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#
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# NORMAL_3:
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# NORMAL_2: TEST2a
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# NORMAL_1: Elaboration of TEST1
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# NORMAL:
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#
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# The epilogue of TEST2a emits it immediately:
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#
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# NORMAL_3:
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# NORMAL_2:
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# NORMAL_1: Elaboration of TEST1
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# NORMAL: TEST2a
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#
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# TEST2b then requires TEST3, so right before the epilogue of TEST3, you
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# have:
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#
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# NORMAL_3: TEST3
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# NORMAL_2: Elaboration of TEST2b
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# NORMAL_1: Elaboration of TEST1
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# NORMAL: TEST2a
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#
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# The epilogue of TEST3 emits it:
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#
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# NORMAL_3:
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# NORMAL_2: Elaboration of TEST2b
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# NORMAL_1: Elaboration of TEST1
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# NORMAL: TEST2a; TEST3
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#
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# TEST2b is now completely expanded, and emitted:
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#
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# NORMAL_3:
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# NORMAL_2:
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# NORMAL_1: Elaboration of TEST1
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# NORMAL: TEST2a; TEST3; TEST2b
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#
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# and finally, TEST1 is finished and emitted:
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#
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# NORMAL_3:
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# NORMAL_2:
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# NORMAL_1:
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# NORMAL: TEST2a; TEST3; TEST2b: TEST1
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#
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# The idea, is simple, but the implementation is a bit evolved. If you
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# are like me, you will want to see the actual functioning of this
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# implementation to be convinced. The next section gives the full
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# details.
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#
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#
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# The Axel Thimm implementation at work
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# -------------------------------------
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#
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# We consider the macros above, and this configure.in:
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#
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# AC_INIT
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# TEST1
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#
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# You should keep the definitions of _AC_DEFUN_PRO, _AC_DEFUN_EPI, and
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# AC_REQUIRE at hand to follow the steps.
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#
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# This implements tries not to assume that of the current diversion is
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# NORMAL, so as soon as a macro (AC_DEFUN'd) is expanded, we first
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# record the current diversion under the name _AC_DIVERT_DUMP (denoted
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# DUMP below for short). This introduces an important difference with
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# the previous versions of Autoconf: you cannot use AC_REQUIRE if you
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# were not inside an AC_DEFUN'd macro, and especially, you cannot
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# AC_REQUIRE directly from the top level.
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#
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# We have not tried to simulate the old behavior (better yet, we
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# diagnose it), because it is too dangerous: a macro AC_REQUIRE'd from
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# the top level is expanded before the body of `configure', i.e., before
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# any other test was run. I let you imagine the result of requiring
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# AC_STDC_HEADERS for instance, before AC_PROG_CC was actually run....
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#
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# After AC_INIT was run, the current diversion is NORMAL.
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# * AC_INIT was run
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# DUMP: undefined
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# diversion stack: NORMAL |-
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#
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# * TEST1 is expanded
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# The prologue of TEST1 sets AC_DIVERSION_DUMP, which is the diversion
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# where the current elaboration will be dumped, to the current
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# diversion. It also AC_DIVERT_PUSH to NORMAL_1, where the full
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# expansion of TEST1 and its dependencies will be elaborated.
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# DUMP: NORMAL
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# NORMAL: empty
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# diversions: NORMAL_1, NORMAL |-
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#
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# * TEST1 requires TEST2a: prologue
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# AC_REQUIRE AC_DIVERT_PUSHes another temporary diversion NORMAL_2 (in
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# fact, the diversion whose number is one less than the current
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# diversion), and expands TEST2a in there.
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# DUMP: NORMAL
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# NORMAL: empty
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# diversions: NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST2a is expanded.
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# Its prologue pushes the current diversion again.
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# DUMP: NORMAL
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# NORMAL: empty
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# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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# It is expanded in NORMAL_2, and NORMAL_2 is popped by the epilogue
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# of TEST2a.
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# DUMP: NORMAL
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# NORMAL: nothing
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# NORMAL_2: TEST2a
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# diversions: NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST1 requires TEST2a: epilogue
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# The content of the current diversion is appended to DUMP (and removed
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# from the current diversion). A diversion is popped.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# diversions: NORMAL_1, NORMAL |-
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#
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# * TEST1 requires TEST2b: prologue
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# AC_REQUIRE pushes NORMAL_2 and expands TEST2b.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# diversions: NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST2b is expanded.
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# Its prologue pushes the current diversion again.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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# The body is expanded here.
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#
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# * TEST2b requires TEST3: prologue
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# AC_REQUIRE pushes NORMAL_3 and expands TEST3.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# diversions: NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST3 is expanded.
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# Its prologue pushes the current diversion again.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# diversions: NORMAL_3, NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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# TEST3 requires TEST2a, but TEST2a has already been AC_PROVIDE'd, so
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# nothing happens. It's body is expanded here, and its epilogue pops a
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# diversion.
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# DUMP: NORMAL
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# NORMAL: TEST2a
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# NORMAL_3: TEST3
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# diversions: NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST2b requires TEST3: epilogue
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# The current diversion is appended to DUMP, and a diversion is popped.
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# DUMP: NORMAL
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# NORMAL: TEST2a; TEST3
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# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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# The content of TEST2b is expanded here.
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# DUMP: NORMAL
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# NORMAL: TEST2a; TEST3
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# NORMAL_2: TEST2b,
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# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
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# The epilogue of TEST2b pops a diversion.
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# DUMP: NORMAL
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# NORMAL: TEST2a; TEST3
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# NORMAL_2: TEST2b,
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# diversions: NORMAL_2, NORMAL_1, NORMAL |-
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#
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# * TEST1 requires TEST2b: epilogue
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# The current diversion is appended to DUMP, and a diversion is popped.
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# DUMP: NORMAL
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# NORMAL: TEST2a; TEST3; TEST2b
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# diversions: NORMAL_1, NORMAL |-
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#
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# * TEST1 is expanded: epilogue
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# TEST1's own content is in NORMAL_1, and it's epilogue pops a diversion.
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# DUMP: NORMAL
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# NORMAL: TEST2a; TEST3; TEST2b
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# NORMAL_1: TEST1
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# diversions: NORMAL |-
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# Here, the epilogue of TEST1 notices the elaboration is done because
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# DUMP and the current diversion are the same, it then undiverts
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# NORMAL_1 by hand, and undefines DUMP.
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# DUMP: undefined
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# NORMAL: TEST2a; TEST3; TEST2b; TEST1
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# diversions: NORMAL |-
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# _AC_DEFUN_PRO(MACRO-NAME)
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# -------------------------
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# The prologue for Autoconf macros.
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define([_AC_DEFUN_PRO],
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[AC_PROVIDE([$1])dnl
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ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
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[AC_DIVERT_PUSH(m4_eval(AC_DIVERT_DIVERSION - 1))],
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[pushdef([AC_DIVERT_DIVERSION], AC_DIVERT_DIVERSION)])dnl
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ifdef([_AC_DIVERT_DUMP],
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[AC_DIVERT_PUSH(defn([AC_DIVERT_DIVERSION]))],
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[define([_AC_DIVERT_DUMP], defn([AC_DIVERT_DIVERSION]))dnl
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AC_DIVERT_PUSH([NORMAL_1])])dnl
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])
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@ -205,12 +491,9 @@ ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
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# the PRO/EPI pairs.
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define([_AC_DEFUN_EPI],
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[AC_DIVERT_POP()dnl
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ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
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[undivert(_AC_DIVERT([NORMAL_4]))dnl
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undivert(_AC_DIVERT([NORMAL_3]))dnl
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undivert(_AC_DIVERT([NORMAL_2]))dnl
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undivert(_AC_DIVERT([NORMAL_1]))dnl
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])dnl
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ifelse(_AC_DIVERT_DUMP, AC_DIVERT_DIVERSION,
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[undivert(_AC_DIVERT([NORMAL_1]))dnl
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undefine([_AC_DIVERT_DUMP])])dnl
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])
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@ -270,11 +553,16 @@ define([AC_BEFORE],
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# AC_REQUIRE(MACRO-NAME)
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# ----------------------
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# If MACRO-NAME has never been expanded, expand it *before* the current
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# macro expansion.
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# macro expansion. Once expanded, emit it in _AC_DIVERT_DUMP.
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define([AC_REQUIRE],
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[AC_PROVIDE_IFELSE([$1],
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[],
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[AC_DIVERT(m4_eval(AC_DIVERT_DIVERSION - 1), [$1])])dnl
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[ifndef([_AC_DIVERT_DUMP],
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[AC_FATAL([$0: cannot be used out of an AC_DEFUN'd macro])])dnl
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AC_PROVIDE_IFELSE([$1],
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[],
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[AC_DIVERT_PUSH(m4_eval(AC_DIVERT_DIVERSION - 1))dnl
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$1
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divert(_AC_DIVERT_DUMP)undivert(AC_DIVERT_DIVERSION)dnl
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AC_DIVERT_POP()])dnl
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AC_PROVIDE_IFELSE([$1],
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[],
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[AC_DIAGNOSE([syntax],
|
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|
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@ -187,15 +187,301 @@ pushdef([AC_DIVERT_DIVERSION], _AC_DIVERT([KILL]))
|
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## Defining macros in autoconf::. ##
|
||||
## ------------------------------- ##
|
||||
|
||||
# `AC_DEFUN' is basically `define' but it equips the macro with the
|
||||
# needed machinery for `AC_REQUIRE'. A macro must be AC_DEFUN'd if
|
||||
# either it is AC_REQUIRE'd, or it AC_REQUIRE's.
|
||||
#
|
||||
# Of course AC_DEFUN AC_PROVIDE's the macro, so that a macro which has
|
||||
# been expanded is not expanded again when AC_REQUIRE'd, but the
|
||||
# difficult part is the proper expansion of macros when they are
|
||||
# AC_REQUIRE'd.
|
||||
#
|
||||
# The implementation is based on two ideas, (i) using diversions to
|
||||
# prepare the expansion of the macro and its dependencies (by François
|
||||
# Pinard), and (ii) expand the most recently AC_REQUIRE'd macros _after_
|
||||
# the previous macros (by Axel Thimm).
|
||||
#
|
||||
#
|
||||
# The first idea: why using diversions?
|
||||
# -------------------------------------
|
||||
#
|
||||
# When a macro requires another, the other macro is expanded in new
|
||||
# diversion, NORMAL_1. When the outer macro is fully expanded, we first
|
||||
# undivert the most nested diversions (NORMAL_2...), and finally
|
||||
# undivert NORMAL_1. To understand why we need several diversions,
|
||||
# consider the following example:
|
||||
#
|
||||
# | AC_DEFUN([TEST1], [Test...REQUIRE([TEST2])1])
|
||||
# | AC_DEFUN([TEST2], [Test...REQUIRE([TEST3])2])
|
||||
# | AC_DEFUN([TEST3], [Test...3])
|
||||
#
|
||||
# Because AC_REQUIRE is not required to be first in the outer macros, we
|
||||
# must keep the expansions of the various level of AC_REQUIRE separated.
|
||||
# Right before executing the epilogue of TEST1, we have:
|
||||
#
|
||||
# NORMAL_3: Test...3
|
||||
# NORMAL_1: Test...2
|
||||
# NORMAL_1: Test...1
|
||||
# NORMAL:
|
||||
#
|
||||
# Finally the epilogue of TEST1 undiverts NORMAL_3, 2, and 1 into the
|
||||
# regular flow, NORMAL.
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_1:
|
||||
# NORMAL_1:
|
||||
# NORMAL: 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:
|
||||
#
|
||||
# | AC_DEFUN([TEST1], [REQUIRE([TEST2a])REQUIRE([TEST2b])])
|
||||
# | AC_DEFUN([TEST2a], [])
|
||||
# | AC_DEFUN([TEST2b], [REQUIRE([TEST3])])
|
||||
# | AC_DEFUN([TEST3], [REQUIRE([TEST2a])])
|
||||
# |
|
||||
# | AC_INIT
|
||||
# | TEST1
|
||||
#
|
||||
# The dependencies between the macros are:
|
||||
#
|
||||
# 3 --- 2b
|
||||
# / \ is AC_REQUIRE'd by
|
||||
# / \ left -------------------- right
|
||||
# 2a ------------ 1
|
||||
#
|
||||
# If you strictly apply the rules given in the previous section you get:
|
||||
#
|
||||
# NORMAL_3: TEST3
|
||||
# NORMAL_2: TEST2a; TEST2b
|
||||
# NORMAL_1: TEST1
|
||||
# NORMAL:
|
||||
#
|
||||
# (TEST2a, although required by TEST3 is not expanded in NORMAL_4
|
||||
# because is has already been expanded before in NORMAL_2, so it has
|
||||
# been AC_PROVIDE'd, so it is not expanded again) so when you undivert
|
||||
# the stack of diversions, you get:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2:
|
||||
# NORMAL_1:
|
||||
# NORMAL: TEST3; TEST2a; TEST2b; TEST1
|
||||
#
|
||||
# i.e., TEST2a is expanded after TEST3 although the latter required the
|
||||
# former.
|
||||
#
|
||||
# Starting from 2.50, uses an implementation provided by Axel Thimm.
|
||||
# The idea is simple: the order in which macros are emitted must be the
|
||||
# same as the one in which macro are expanded. (The bug above can
|
||||
# indeed be described as: a macro has been AC_PROVIDE'd, but it is
|
||||
# emitted after: the lack of correlation between emission and expansion
|
||||
# order is guilty).
|
||||
#
|
||||
# How to do that? You keeping the stack of diversions to elaborate the
|
||||
# macros, but each time a macro is fully expanded, emit it immediately.
|
||||
#
|
||||
# In the example above, when TEST2a is expanded, but it's epilogue is
|
||||
# not run yet, you have:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2: TEST2a
|
||||
# NORMAL_1: Elaboration of TEST1
|
||||
# NORMAL:
|
||||
#
|
||||
# The epilogue of TEST2a emits it immediately:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2:
|
||||
# NORMAL_1: Elaboration of TEST1
|
||||
# NORMAL: TEST2a
|
||||
#
|
||||
# TEST2b then requires TEST3, so right before the epilogue of TEST3, you
|
||||
# have:
|
||||
#
|
||||
# NORMAL_3: TEST3
|
||||
# NORMAL_2: Elaboration of TEST2b
|
||||
# NORMAL_1: Elaboration of TEST1
|
||||
# NORMAL: TEST2a
|
||||
#
|
||||
# The epilogue of TEST3 emits it:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2: Elaboration of TEST2b
|
||||
# NORMAL_1: Elaboration of TEST1
|
||||
# NORMAL: TEST2a; TEST3
|
||||
#
|
||||
# TEST2b is now completely expanded, and emitted:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2:
|
||||
# NORMAL_1: Elaboration of TEST1
|
||||
# NORMAL: TEST2a; TEST3; TEST2b
|
||||
#
|
||||
# and finally, TEST1 is finished and emitted:
|
||||
#
|
||||
# NORMAL_3:
|
||||
# NORMAL_2:
|
||||
# NORMAL_1:
|
||||
# NORMAL: 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.in:
|
||||
#
|
||||
# AC_INIT
|
||||
# TEST1
|
||||
#
|
||||
# You should keep the definitions of _AC_DEFUN_PRO, _AC_DEFUN_EPI, and
|
||||
# AC_REQUIRE at hand to follow the steps.
|
||||
#
|
||||
# This implements tries not to assume that of the current diversion is
|
||||
# NORMAL, so as soon as a macro (AC_DEFUN'd) is expanded, we first
|
||||
# record the current diversion under the name _AC_DIVERT_DUMP (denoted
|
||||
# DUMP below for short). This introduces an important difference with
|
||||
# the previous versions of Autoconf: you cannot use AC_REQUIRE if you
|
||||
# were not inside an AC_DEFUN'd macro, and especially, you cannot
|
||||
# AC_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 AC_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 NORMAL.
|
||||
# * AC_INIT was run
|
||||
# DUMP: undefined
|
||||
# diversion stack: NORMAL |-
|
||||
#
|
||||
# * TEST1 is expanded
|
||||
# The prologue of TEST1 sets AC_DIVERSION_DUMP, which is the diversion
|
||||
# where the current elaboration will be dumped, to the current
|
||||
# diversion. It also AC_DIVERT_PUSH to NORMAL_1, where the full
|
||||
# expansion of TEST1 and its dependencies will be elaborated.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: empty
|
||||
# diversions: NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST1 requires TEST2a: prologue
|
||||
# AC_REQUIRE AC_DIVERT_PUSHes another temporary diversion NORMAL_2 (in
|
||||
# fact, the diversion whose number is one less than the current
|
||||
# diversion), and expands TEST2a in there.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: empty
|
||||
# diversions: NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST2a is expanded.
|
||||
# Its prologue pushes the current diversion again.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: empty
|
||||
# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
# It is expanded in NORMAL_2, and NORMAL_2 is popped by the epilogue
|
||||
# of TEST2a.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: nothing
|
||||
# NORMAL_2: TEST2a
|
||||
# diversions: NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST1 requires TEST2a: epilogue
|
||||
# The content of the current diversion is appended to DUMP (and removed
|
||||
# from the current diversion). A diversion is popped.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# diversions: NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST1 requires TEST2b: prologue
|
||||
# AC_REQUIRE pushes NORMAL_2 and expands TEST2b.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# diversions: NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST2b is expanded.
|
||||
# Its prologue pushes the current diversion again.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
# The body is expanded here.
|
||||
#
|
||||
# * TEST2b requires TEST3: prologue
|
||||
# AC_REQUIRE pushes NORMAL_3 and expands TEST3.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# diversions: NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST3 is expanded.
|
||||
# Its prologue pushes the current diversion again.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# diversions: NORMAL_3, NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
# TEST3 requires TEST2a, but TEST2a has already been AC_PROVIDE'd, so
|
||||
# nothing happens. It's body is expanded here, and its epilogue pops a
|
||||
# diversion.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a
|
||||
# NORMAL_3: TEST3
|
||||
# diversions: NORMAL_3, NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST2b requires TEST3: epilogue
|
||||
# The current diversion is appended to DUMP, and a diversion is popped.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a; TEST3
|
||||
# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
# The content of TEST2b is expanded here.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a; TEST3
|
||||
# NORMAL_2: TEST2b,
|
||||
# diversions: NORMAL_2, NORMAL_2, NORMAL_1, NORMAL |-
|
||||
# The epilogue of TEST2b pops a diversion.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a; TEST3
|
||||
# NORMAL_2: TEST2b,
|
||||
# diversions: NORMAL_2, NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST1 requires TEST2b: epilogue
|
||||
# The current diversion is appended to DUMP, and a diversion is popped.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a; TEST3; TEST2b
|
||||
# diversions: NORMAL_1, NORMAL |-
|
||||
#
|
||||
# * TEST1 is expanded: epilogue
|
||||
# TEST1's own content is in NORMAL_1, and it's epilogue pops a diversion.
|
||||
# DUMP: NORMAL
|
||||
# NORMAL: TEST2a; TEST3; TEST2b
|
||||
# NORMAL_1: TEST1
|
||||
# diversions: NORMAL |-
|
||||
# Here, the epilogue of TEST1 notices the elaboration is done because
|
||||
# DUMP and the current diversion are the same, it then undiverts
|
||||
# NORMAL_1 by hand, and undefines DUMP.
|
||||
# DUMP: undefined
|
||||
# NORMAL: TEST2a; TEST3; TEST2b; TEST1
|
||||
# diversions: NORMAL |-
|
||||
|
||||
|
||||
# _AC_DEFUN_PRO(MACRO-NAME)
|
||||
# -------------------------
|
||||
# The prologue for Autoconf macros.
|
||||
define([_AC_DEFUN_PRO],
|
||||
[AC_PROVIDE([$1])dnl
|
||||
ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
|
||||
[AC_DIVERT_PUSH(m4_eval(AC_DIVERT_DIVERSION - 1))],
|
||||
[pushdef([AC_DIVERT_DIVERSION], AC_DIVERT_DIVERSION)])dnl
|
||||
ifdef([_AC_DIVERT_DUMP],
|
||||
[AC_DIVERT_PUSH(defn([AC_DIVERT_DIVERSION]))],
|
||||
[define([_AC_DIVERT_DUMP], defn([AC_DIVERT_DIVERSION]))dnl
|
||||
AC_DIVERT_PUSH([NORMAL_1])])dnl
|
||||
])
|
||||
|
||||
|
||||
@ -205,12 +491,9 @@ ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
|
||||
# the PRO/EPI pairs.
|
||||
define([_AC_DEFUN_EPI],
|
||||
[AC_DIVERT_POP()dnl
|
||||
ifelse(AC_DIVERT_DIVERSION, _AC_DIVERT([NORMAL]),
|
||||
[undivert(_AC_DIVERT([NORMAL_4]))dnl
|
||||
undivert(_AC_DIVERT([NORMAL_3]))dnl
|
||||
undivert(_AC_DIVERT([NORMAL_2]))dnl
|
||||
undivert(_AC_DIVERT([NORMAL_1]))dnl
|
||||
])dnl
|
||||
ifelse(_AC_DIVERT_DUMP, AC_DIVERT_DIVERSION,
|
||||
[undivert(_AC_DIVERT([NORMAL_1]))dnl
|
||||
undefine([_AC_DIVERT_DUMP])])dnl
|
||||
])
|
||||
|
||||
|
||||
@ -270,11 +553,16 @@ define([AC_BEFORE],
|
||||
# AC_REQUIRE(MACRO-NAME)
|
||||
# ----------------------
|
||||
# If MACRO-NAME has never been expanded, expand it *before* the current
|
||||
# macro expansion.
|
||||
# macro expansion. Once expanded, emit it in _AC_DIVERT_DUMP.
|
||||
define([AC_REQUIRE],
|
||||
[AC_PROVIDE_IFELSE([$1],
|
||||
[],
|
||||
[AC_DIVERT(m4_eval(AC_DIVERT_DIVERSION - 1), [$1])])dnl
|
||||
[ifndef([_AC_DIVERT_DUMP],
|
||||
[AC_FATAL([$0: cannot be used out of an AC_DEFUN'd macro])])dnl
|
||||
AC_PROVIDE_IFELSE([$1],
|
||||
[],
|
||||
[AC_DIVERT_PUSH(m4_eval(AC_DIVERT_DIVERSION - 1))dnl
|
||||
$1
|
||||
divert(_AC_DIVERT_DUMP)undivert(AC_DIVERT_DIVERSION)dnl
|
||||
AC_DIVERT_POP()])dnl
|
||||
AC_PROVIDE_IFELSE([$1],
|
||||
[],
|
||||
[AC_DIAGNOSE([syntax],
|
||||
|
||||
@ -6,8 +6,8 @@ Base layer.
|
||||
|
||||
EOF
|
||||
|
||||
# AU_DEFUN
|
||||
# --------
|
||||
# m4_wrap
|
||||
# -------
|
||||
|
||||
AT_SETUP(m4_wrap)
|
||||
|
||||
@ -50,5 +50,45 @@ First, second , third, [,quoted]
|
||||
|
||||
AT_CHECK([$M4 -I $at_top_srcdir libm4.in], 0, expout)
|
||||
|
||||
|
||||
AT_CLEANUP()
|
||||
|
||||
|
||||
|
||||
# AC_REQUIRE
|
||||
# ----------
|
||||
|
||||
# Check that dependencies are always properly honored.
|
||||
|
||||
AT_SETUP(AC_REQUIRE)
|
||||
|
||||
AT_DATA(configure.in,
|
||||
[[define([REQUIRE_AND_CHECK],
|
||||
[AC_REQUIRE([$1])dnl
|
||||
test -z "$translit([$1], [A-Z], [a-z])" && exit 1])
|
||||
|
||||
AC_DEFUN([TEST1],
|
||||
[REQUIRE_AND_CHECK([TEST2a])
|
||||
REQUIRE_AND_CHECK([TEST2b])
|
||||
test1=set])
|
||||
|
||||
AC_DEFUN([TEST2a],
|
||||
[test2a=set])
|
||||
|
||||
AC_DEFUN([TEST2b],
|
||||
[REQUIRE_AND_CHECK([TEST3])
|
||||
test2b=set])
|
||||
|
||||
AC_DEFUN([TEST3],
|
||||
[REQUIRE_AND_CHECK([TEST2a])
|
||||
test3=set])
|
||||
|
||||
AC_DIVERT_POP()
|
||||
TEST1
|
||||
test -z "$test1" && exit 1
|
||||
exit 0
|
||||
]])
|
||||
|
||||
AT_CHECK([../autoconf -m .. -l $at_srcdir], 0, [], [])
|
||||
AT_CHECK([./configure], 0)
|
||||
|
||||
AT_CLEANUP(configure)
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user