Re: M4 syntax $11 vs. ${11}

Index: NEWS
===================================================================
RCS file: /sources/m4/m4/NEWS,v
retrieving revision 1.1.1.1.2.95
diff -u -p -r1.1.1.1.2.95 NEWS
--- NEWS	24 Feb 2007 17:32:58 -0000	1.1.1.1.2.95
+++ NEWS	28 Feb 2007 13:41:35 -0000
@@ -2,6 +2,10 @@ GNU M4 NEWS - User visible changes.
 Copyright (C) 1992, 1993, 1994, 2004, 2005, 2006, 2007 Free Software
 Foundation, Inc.
 
+Version 1.4.9 - ?? ??? 2007, by ???  (CVS version 1.4.8c)
+
+* Minor documentation and portability cleanups.
+
 Version 1.4.8b - 24 Feb 2007, by Eric Blake  (CVS version 1.4.8a)
 
 * Fix a regression introduced in 1.4.8 that made m4 unable to process
Index: configure.ac
===================================================================
RCS file: /sources/m4/m4/configure.ac,v
retrieving revision 1.36.2.35
diff -u -p -r1.36.2.35 configure.ac
--- configure.ac	24 Feb 2007 17:32:58 -0000	1.36.2.35
+++ configure.ac	28 Feb 2007 13:41:35 -0000
@@ -18,7 +18,7 @@
 # 02110-1301  USA
 
 AC_PREREQ([2.60])
-AC_INIT([GNU M4], [1.4.8b], [[email protected]])
+AC_INIT([GNU M4], [1.4.8c], [[email protected]])
 AM_INIT_AUTOMAKE([1.9.6 dist-bzip2 gnu])
 PACKAGE=$PACKAGE_TARNAME; AC_SUBST([PACKAGE])
 VERSION=$PACKAGE_VERSION; AC_SUBST([VERSION])
Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.1.1.1.2.115
diff -u -p -r1.1.1.1.2.115 m4.texinfo
--- doc/m4.texinfo	24 Feb 2007 14:02:23 -0000	1.1.1.1.2.115
+++ doc/m4.texinfo	28 Feb 2007 13:41:36 -0000
@@ -618,13 +618,12 @@ input came from.  These features occur w
 @table @code
 @item -D @var{NAME}@r{[}=@var{VALUE}@r{]}
 @itemx --define=@var{NAME}@r{[}=@var{VALUE}@r{]}
-This enters @var{NAME} into the symbol table, before any input files are
-read.  If @samp{=@var{VALUE}} is missing, the value is taken to be the
-empty string.  The @var{VALUE} can be any string, and the macro can be
-defined to take arguments, just as if it was defined from within the
-input.  This option may be given more than once; order with respect to
-file names is significant, and redefining the same @var{NAME} loses the
-previous value.
+This enters @var{NAME} into the symbol table.  If @samp{=@var{VALUE}} is
+missing, the value is taken to be the empty string.  The @var{VALUE} can
+be any string, and the macro can be defined to take arguments, just as
+if it was defined from within the input.  This option may be given more
+than once; order with respect to file names is significant, and
+redefining the same @var{NAME} loses the previous value.
 
 @item -I @var{DIRECTORY}
 @itemx --include=@var{DIRECTORY}
@@ -1615,9 +1614,9 @@ consist of one or more digits, allowing 
 arguments.  The extension of accepting multiple digits is incompatible
 with @acronym{POSIX}, and is different than traditional implementations
 of @code{m4}, which only recognize one digit.  Therefore, future
-versions of @acronym{GNU} M4 will phase out this feature.
-@xref{Extensions}, for an example of how to portably access the eleventh
-argument.
+versions of @acronym{GNU} M4 will phase out this feature.  To portably
+access beyond the ninth argument, you can use the @code{argn} macro
+documented later (@pxref{Shift}).
 
 @acronym{POSIX} also states that @samp{$} followed immediately by
 @samp{@{} in a macro definition is implementation-defined.  This version
@@ -1645,10 +1644,10 @@ behavior due to the changed behavior of 
 @option{--warn-macro-sequence} command-line option (@pxref{Operation
 modes, , Invoking m4}) with the default regular expression.  This will
 add a warning any time a macro definition includes @samp{$} followed by
-multiple digits, or by @samp{@{} and a digit.  The warning is not
-enabled by default, because it triggers a number of warnings in Autoconf
-2.61 (and Autoconf uses @option{-E} to treat warnings as errors), and
-because it will still be possible to restore older behavior in M4 2.0.
+multiple digits, or by @samp{@{}.  The warning is not enabled by
+default, because it triggers a number of warnings in Autoconf 2.61 (and
+Autoconf uses @option{-E} to treat warnings as errors), and because it
+will still be possible to restore older behavior in M4 2.0.
 
 @comment ignore
 @example
@@ -2439,6 +2438,34 @@ undivert(`quote.m4')dnl
 @result{}divert`'dnl
 @end example
 
+@cindex nine arguments, more than
+@cindex more than nine arguments
+@cindex arguments, more than nine
+One more useful macro based on @code{shift} allows portably selecting
+an arbitrary argument (usually greater than the ninth argument), without
+relying on the @acronym{GNU} extension of multi-digit arguments
+(@pxref{Arguments}).
+
+@deffn Composite argn (@var{n}, @dots{})
+Expands to argument @var{n} out of the remaining arguments.  @var{n}
+must be a positive number.  Usually invoked as
+@samp{argn(`@var{n}',$@@)}.
+@end deffn
+
+It is implemented as:
+
+@example
+define(`argn', `ifelse(`$1', 1, ``$2'',
+  `argn(decr(`$1'), shift(shift($@@)))')')
+@result{}
+argn(`1', `a')
+@result{}a
+define(`foo', `argn(`11', $@@)')
+@result{}
+foo(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k', `l')
+@result{}k
+@end example
+
 @node Forloop
 @section Iteration by counting
 
@@ -5716,6 +5743,9 @@ Eleventh(`a', `b', `c', `d', `e', `f', `
 @result{}k
 @end example
 
+@noindent
+Also see the @code{argn} macro (@pxref{Shift}).
+
 @item
 The @code{divert} (@pxref{Divert}) macro can manage more than 9
 diversions.  @acronym{GNU} @code{m4} treats all positive numbers as valid
Index: src/builtin.c
===================================================================
RCS file: /sources/m4/m4/src/Attic/builtin.c,v
retrieving revision 1.1.1.1.2.58
diff -u -p -r1.1.1.1.2.58 builtin.c
--- src/builtin.c	24 Feb 2007 14:02:23 -0000	1.1.1.1.2.58
+++ src/builtin.c	28 Feb 2007 13:41:36 -0000
@@ -253,7 +253,7 @@ set_macro_sequence (const char *regexp)
   const char *msg;
 
   if (! regexp)
-    regexp = "\\$\\({[^}]*}\\|[0-9][0-9]+\\)";
+    regexp = DEFAULT_MACRO_SEQUENCE;
   else if (regexp[0] == '\0')
     {
       macro_sequence_inuse = false;
@@ -328,7 +328,7 @@ define_user_macro (const char *name, con
 	}
       if (offset == -2)
 	M4ERROR ((warning_status, 0,
-		  "error checking --warn-define-sequence for macro `%s'",
+		  "error checking --warn-macro-sequence for macro `%s'",
 		  name));
     }
 }
Index: src/m4.c
===================================================================
RCS file: /sources/m4/m4/src/Attic/m4.c,v
retrieving revision 1.1.1.1.2.45
diff -u -p -r1.1.1.1.2.45 m4.c
--- src/m4.c	24 Feb 2007 14:02:23 -0000	1.1.1.1.2.45
+++ src/m4.c	28 Feb 2007 13:41:36 -0000
@@ -154,7 +154,7 @@ Operation modes:\n\
       --help                   display this help and exit\n\
       --version                output version information and exit\n\
 ", stdout);
-      fputs ("\
+      printf ("\
   -E, --fatal-warnings         once: warnings become errors, twice: stop\n\
                                execution at first error\n\
   -i, --interactive            unbuffer output, ignore interrupts\n\
@@ -162,8 +162,8 @@ 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\
-", stdout);
+                               default %s\n\
+", DEFAULT_MACRO_SEQUENCE);
 #ifdef ENABLE_CHANGEWORD
       fputs ("\
   -W, --word-regexp=REGEXP     use REGEXP for macro name syntax\n\
Index: src/m4.h
===================================================================
RCS file: /sources/m4/m4/src/m4.h,v
retrieving revision 1.1.1.1.2.40
diff -u -p -r1.1.1.1.2.40 m4.h
--- src/m4.h	23 Feb 2007 17:05:27 -0000	1.1.1.1.2.40
+++ src/m4.h	28 Feb 2007 13:41:36 -0000
@@ -407,6 +407,11 @@ typedef struct predefined predefined;
 struct re_pattern_buffer;
 struct re_registers;
 
+/* The default sequence detects multi-digit parameters (obsolete after
+   1.4.x), and any use of extended arguments with the default ${}
+   syntax (new in 2.0).  */
+#define DEFAULT_MACRO_SEQUENCE "\\$\\({[^}]*}\\|[0-9][0-9]+\\)"
+
 void builtin_init (void);
 void define_builtin (const char *, const builtin *, symbol_lookup);
 void set_macro_sequence (const char *);