Re: Comments on changesyntax et al.

[Eric Blake]

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According to Eric Blake on 2/10/2007 4:22 PM:
> 
> Paul convinced me that for purposes
> of a transition period, only ${<digit> should be recognized as
> the start of an extended argument.  On the other hand, that was
> before we came up with the idea for multi-character extended
> argument delimiters, so maybe I should just reserve ALL ${
> sequences in the default warning of M4 1.4.9's --warn-macro-sequence.

I decided with the flexibility of the regex in --warn-macro-sequence in
1.4.9, and the promised flexibility of changeextarg (yet to be
implemented) in 2.0, that we might as well make the default regex warn
about all uses of ${.  Like so:

2007-02-24  Eric Blake  <address@hidden>

        Reserve all uses of raw ${} in macro definitions, not just
        ${<digit>}.
        * src/builtin.c (set_macro_sequence): Change default macro
        sequence.
        * doc/m4.texinfo (Operation modes): Update to match.
        * src/m4.c (usage): Likewise.
        * NEWS: Likewise.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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Index: NEWS
===================================================================
RCS file: /sources/m4/m4/NEWS,v
retrieving revision 1.1.1.1.2.93
diff -u -p -r1.1.1.1.2.93 NEWS
--- NEWS        8 Feb 2007 14:52:29 -0000       1.1.1.1.2.93
+++ NEWS        24 Feb 2007 14:01:22 -0000
@@ -23,9 +23,9 @@ Version 1.4.9 - ?? ??? 2007, by ????  (C
 * A new `--warn-macro-sequence' command-line option allows detection of
   sequences in `define' and `pushdef' definitions that match an optional
   regular expression.  The default regular expression is
-  `\$\({[0-9][^}]*}\|[0-9][0-9]+\)', corresponding to the sequences that
-  might not behave correctly when upgrading to the eventual M4 2.0.  By
-  default, M4 2.0 will follow the POSIX requirement that a macro definition
+  `\$\({[^}]*}\|[0-9][0-9]+\)', corresponding to the sequences that might
+  not behave correctly when upgrading to the eventual M4 2.0.  By default,
+  M4 2.0 will follow the POSIX requirement that a macro definition
   containing `$11' must expand to the first argument concatenated with 1,
   rather than the eleventh argument; and will take advantage of the POSIX
   wording that allows implementations to treat `${11}' as the eleventh
Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.1.1.1.2.114
diff -u -p -r1.1.1.1.2.114 m4.texinfo
--- doc/m4.texinfo      8 Feb 2007 14:52:29 -0000       1.1.1.1.2.114
+++ doc/m4.texinfo      24 Feb 2007 14:01:24 -0000
@@ -590,13 +590,13 @@ match in any macro definition (either by
 @code{pushdef}).  Empty matches are ignored; therefore, supplying the
 empty string as @var{REGEXP} disables any warning.  If the optional
 @var{REGEXP} is not supplied, then the default regular expression is
address@hidden(@address@hidden@}\|[0-9][0-9]+\)} (a literal @samp{$} followed
-by multiple digits or by an open brace and a digit), since these
-sequences will change semantics in the default operation of
address@hidden M4 2.0 (due to a change in how more than 9 arguments in a
-macro definition will be handled, @pxref{Arguments}).  Providing an
-alternate regular expression can provide a useful reverse lookup feature
-of finding where a macro is defined to have a given definition.
address@hidden(@address@hidden@}\|[0-9][0-9]+\)} (a literal @samp{$} followed by
+multiple digits or by an open brace), since these sequences will
+change semantics in the default operation of @acronym{GNU} M4 2.0 (due
+to a change in how more than 9 arguments in a macro definition will be
+handled, @pxref{Arguments}).  Providing an alternate regular
+expression can provide a useful reverse lookup feature of finding
+where a macro is defined to have a given definition.
 
 @item -W @var{REGEXP}
 @itemx address@hidden
@@ -6388,7 +6388,7 @@ the first time.
 @bye
 
 @c Local Variables:
address@hidden coding: ISO-8859-1
address@hidden coding: iso-8859-1
 @c fill-column: 72
 @c ispell-local-dictionary: "american"
 @c indent-tabs-mode: nil
Index: src/builtin.c
===================================================================
RCS file: /sources/m4/m4/src/Attic/builtin.c,v
retrieving revision 1.1.1.1.2.57
diff -u -p -r1.1.1.1.2.57 builtin.c
--- src/builtin.c       8 Feb 2007 14:52:29 -0000       1.1.1.1.2.57
+++ src/builtin.c       24 Feb 2007 14:01:24 -0000
@@ -253,7 +253,7 @@ set_macro_sequence (const char *regexp)
   const char *msg;
 
   if (! regexp)
-    regexp = "\\$\\({[0-9][^}]*}\\|[0-9][0-9]+\\)";
+    regexp = "\\$\\({[^}]*}\\|[0-9][0-9]+\\)";
   else if (regexp[0] == '\0')
     {
       macro_sequence_inuse = false;
Index: src/m4.c
===================================================================
RCS file: /sources/m4/m4/src/Attic/m4.c,v
retrieving revision 1.1.1.1.2.44
diff -u -p -r1.1.1.1.2.44 m4.c
--- src/m4.c    8 Feb 2007 14:52:29 -0000       1.1.1.1.2.44
+++ src/m4.c    24 Feb 2007 14:01:24 -0000
@@ -162,7 +162,7 @@ Operation modes:\n\
   -Q, --quiet, --silent        suppress some warnings for builtins\n\
       --warn-macro-sequence[=REGEXP]\n\
                                warn if macro definition matches REGEXP,\n\
-                               default \\$\\({[0-9][^}]*}\\|[0-9]+\\)\n\
+                               default \\$\\({[^}]*}\\|[0-9][0-9]+\\)\n\
 ", stdout);
 #ifdef ENABLE_CHANGEWORD
       fputs ("\