Changes to m4/doc/m4.texinfo,v [branch-1_4]

[Eric Blake]

CVSROOT:        /sources/m4
Module name:    m4
Branch:         branch-1_4
Changes by:     Eric Blake <ericb>      06/07/12 13:27:26

Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.1.1.1.2.37
retrieving revision 1.1.1.1.2.38
diff -u -b -r1.1.1.1.2.37 -r1.1.1.1.2.38
--- doc/m4.texinfo      12 Jul 2006 13:14:51 -0000      1.1.1.1.2.37
+++ doc/m4.texinfo      12 Jul 2006 13:27:26 -0000      1.1.1.1.2.38
@@ -3996,6 +3996,31 @@
 This allows macros in GNU @code{m4} to take any number of arguments, and
 not only nine (@pxref{Arguments}).
 
+This means that @code{define(`foo', `$11')} is ambiguous between
+implementations.  To portably choose between grabbing the first
+parameter and appending 1 to the expansion, or grabbing the eleventh
+parameter, you can do the following:
+
address@hidden
+define(`a1', `A1')
address@hidden
+dnl First argument, concatenated with 1
+define(`_1', `$1')define(`first1', `_1($@@)1')
address@hidden
+dnl Eleventh argument, portable
+define(`_9', `$9')define(`eleventh', `_9(shift(shift($@@)))')
address@hidden
+dnl Eleventh argument, GNU style
+define(`Eleventh', `$11')
address@hidden
+first1(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
address@hidden
+eleventh(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
address@hidden
+Eleventh(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
address@hidden
address@hidden example
+
 @item
 The @code{divert} (@pxref{Divert}) macro can manage more than 9
 diversions.  GNU @code{m4} treats all positive numbers as valid