Hello Autoconfers,
I hit a weird (to me) issue involving m4_map(all) and AC_REQUIRE, and I
would appreciate some help understanding what's going on here!
So normally when expanding a macro defined with AC_DEFUN and a nested
AC_REQUIRE causes a macro to be expanded, that expansion gets "hoisted"
outside of the topmost macro expansion. Example:
AC_INIT([test], [0])
AC_DEFUN([DEF0], [echo def0])
AC_DEFUN([REQ0], [AC_REQUIRE([DEF0])])
AC_DEFUN([TEST0], [m4_newline([echo hello])[]m4_newline([REQ0])])
TEST0
When I run this, I see:
def0
hello
which is as expected.
But when my macro is using m4_map or m4_mapall, this mechanism seems to
break down. Example:
AC_INIT([test], [0])
AC_DEFUN([DEF1], [echo def1])
AC_DEFUN([REQ1], [AC_REQUIRE([DEF1])])
AC_DEFUN([TEST1], [m4_mapall([m4_newline], [[echo hello], [REQ1]])])
TEST1
When I run that, I get:
hello
def1
with the order reversed from my expectation...
But if I implement my own version of mapall in a straightforward way,
it seems to work out just fine:
AC_INIT([test], [0])
AC_DEFUN([DEF2], [echo def2])
AC_DEFUN([REQ2], [AC_REQUIRE([DEF2])])
m4_define([my_mapall], [m4_ifval([$2],
[m4_indir([$1], m4_car($2))[]my_mapall([$1], m4_cdr($2))])])
AC_DEFUN([TEST2], [my_mapall([m4_newline], [[echo hello], [REQ2]])])
TEST2
Running this gives:
def2
hello
as expected.
I really have no idea why TEST1 results in a different expansion from
the other two examples. What exactly is different about m4_mapall?
Thanks,
Nick
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