Re: m4_pattern_forbid matches itself

[Raja R Harinath]

Hi,

Phil Edwards <address@hidden> writes:

> On Thu, Jul 24, 2003 at 02:44:12PM -0500, Raja R Harinath wrote:
>> 
>> That's strange.  It is implemented by a grep.
>> 
>>       foreach (split (/\W+/))
>>         {
>>           $prohibited{$_} = $.
>>             if /$forbidden/o && !/$allowed/o && ! exists $prohibited{$_};
>>         }
>
> Where is this code?  On my system, /usr/bin/m4 is a binary, not a perl
> script.  :-)  I've been trying to dig to learn more, but haven't yet
> retrieved the m4 source.

In $bindir/autom4te.  Somewhat misleadingly, 'm4_pattern_forbid'
isn't part of 'm4', but from the 'm4sugar' library that's part of
'autoconf'.

>> > Any other ideas?  The few examples of m4_pattern_forbid I've seen all
>> > seem to be matching isolated words, e.g., m4_pattern_forbid([^FOO$]),
>> > which clearly won't help for trying to match part of a variable name.
>> 
>> Given the splitting above on \W, that shouldn't be a problem.
>
> I've been trying variations on
>
>     m4_pattern_forbid([\${?target_alias\>],
>                       [target alias is not what you think it is])

I don't know if that'll work, since the \W split will probably
swallow the ${.

- Hari
-- 
Raja R Harinath ------------------------------ address@hidden