FYI: for (i in arr) in AWK

[Akim Demaille]

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * doc/autoconf.texi (Limitations of Usual Tools) <awk>: `for' on
        arrays is nondeterministic across AWK implementations.
        * tests/tools.at (autoconf: forbidden tokens): Sort the error
        message to guarantee its uniqueness.

Index: doc/autoconf.texi
===================================================================
RCS file: /cvs/autoconf/doc/autoconf.texi,v
retrieving revision 1.402
diff -u -u -r1.402 autoconf.texi
--- doc/autoconf.texi 2000/11/30 17:48:50 1.402
+++ doc/autoconf.texi 2000/12/06 15:00:15
@@ -5920,6 +5920,25 @@
 Aaaaarg!
 @end example
 
+If you want your program to be deterministic, don't depend on @code{for}
+on arrays:
+
address@hidden
+$ cat for.awk
+END @{
+  arr["foo"] = 1
+  arr["bar"] = 1
+  for (i in arr)
+    print i
address@hidden
+$ gawk -f for.awk </dev/null
+foo
+bar
+$ nawk -f for.awk </dev/null
+bar
+foo
address@hidden example
+
 
 @item @command{cat}
 @c ----------------
Index: tests/tools.at
===================================================================
RCS file: /cvs/autoconf/tests/tools.at,v
retrieving revision 1.15
diff -u -u -r1.15 tools.at
--- tests/tools.at 2000/12/06 10:53:59 1.15
+++ tests/tools.at 2000/12/06 15:00:16
@@ -186,16 +186,18 @@
 
 
 
-## ------------------ ##
-## Forbidden tokens.  ##
-## ------------------ ##
+## ---------------------------- ##
+## autoconf: forbidden tokens.  ##
+## ---------------------------- ##
 
-AT_SETUP([Forbidden tokens])
+AT_SETUP([autoconf: forbidden tokens])
 
 AT_DATA([configure.in],
 [[AC_PLAIN_SCRIPT()dnl
 
 # This is allowed in spite of the name.
+# It is on purpose that we check the case where there are several
+# tokens on the same line.
 m4_pattern_allow([^AC_ALLOWED$])
 NOT_AC_ALLOWED AC_ALLOWED AC_ALLOWED_NOT
 
@@ -212,17 +214,20 @@
 It would be very bad if Autoconf forgot to expand [AC_]OUTPUT!
 ]])
 
-AT_CHECK([autoconf --autoconf-dir .. -l $at_srcdir], 1, [],
-[[configure.in:5: error: undefined macro: NOT_AC_ALLOWED
-configure.in:5: error: undefined macro: AC_ALLOWED_NOT
-configure.in:8: error: undefined macro: FORBIDDEN
-configure.in:12: error: undefined macro: AC_THIS_IS_INVALID
+AT_CHECK([autoconf --autoconf-dir .. -l $at_srcdir 2>err], 1)
+# The output of autoconf is not deterministic here because it
+# uses `for (ind in array)'.  So be sure to have a unique representation.
+AT_CHECK([sort <err], 0,
+[[configure.in:12: error: undefined macro: AC_THIS_IS_INVALID
 configure.in:12: error: undefined macro: AZ_THIS_IS_INVALID_TOO
 configure.in:13: error: undefined macro: ALTHOUGH_AC_THIS_IS
+configure.in:5: error: undefined macro: AC_ALLOWED_NOT
+configure.in:5: error: undefined macro: NOT_AC_ALLOWED
+configure.in:8: error: undefined macro: FORBIDDEN
 configure:16: error: undefined macro: AC_OUTPUT
 ]])
 
-AT_CLEANUP(configure)
+AT_CLEANUP(configure err)