Re: branch-1_4 doc improvements

[Eric Blake]

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According to Eric Blake on 7/12/2006 7:14 AM:
>>>> Here's another round of doc improvements.

Next - document a workaround for getting traditional behavior for `$11':

2006-07-12  Eric Blake  <address@hidden>

        * doc/m4.texinfo (Extensions): Document how to overcome
        implementation difference in > 9 positional parameters.

- --
Life is short - so eat dessert first!

Eric Blake             address@hidden
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Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.1.1.1.2.37
diff -u -p -r1.1.1.1.2.37 m4.texinfo
--- doc/m4.texinfo      12 Jul 2006 13:14:51 -0000      1.1.1.1.2.37
+++ doc/m4.texinfo      12 Jul 2006 13:25:40 -0000
@@ -3996,6 +3996,31 @@ several digits, while the System V @code
 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:
+
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+define(`a1', `A1')
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+dnl First argument, concatenated with 1
+define(`_1', `$1')define(`first1', `_1($@@)1')
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+dnl Eleventh argument, portable
+define(`_9', `$9')define(`eleventh', `_9(shift(shift($@@)))')
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+dnl Eleventh argument, GNU style
+define(`Eleventh', `$11')
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+first1(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
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+eleventh(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
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+Eleventh(`a', `b', `c', `d', `e', `f', `g', `h', `i', `j', `k')
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+
 @item
 The @code{divert} (@pxref{Divert}) macro can manage more than 9
 diversions.  GNU @code{m4} treats all positive numbers as valid