>I can tighten the definition up. If there have been calls for a
>(?^baz) type construct before, there will be again. It is a matter of
>getting the definition straightforward and useable.
Are you really just wanting !/BAD/ there? That is, something
that isn't matched by /BAD/? One would, of course, normally
simply write !/BAD/, or perhaps !~ /BAD/. However, if reading
a config file of patterns, you can't go invert the sense of the
match.
Well, easily, that is.
The Perl Cookbook, in Chapter 6, has these solutions:
* True if either C</ALPHA/> or C</BETA/> matches, like C</ALPHA/ || /BETA/>:
/ALPHA|BETA/
* True if both C</ALPHA/> and C</BETA/> match, but may overlap, meaning
that C<"BETALPHA"> should be ok, like C</ALPHA/ && /BETA/>:
/^(?=.*ALPHA)(?=.*BETA)/s
* True if both C</ALPHA/> and C</BETA/> match, but may not overlap,
meaning that C<"BETALPHA"> should fail:
/ALPHA.*BETA|BETA.*ALPHA/s
* True if pattern C</PAT/> does not match, like C<$var !~ /PAT/>:
/^(?:(?!PAT).)*$/s
* True if pattern C<BAD> does not match, but pattern C<GOOD> does:
/(?=^(?:(?!BAD).)*$)GOOD/s
I suspect the penultimate is just what you're looking for.
Or shall I go back and deepread the whole thread? :-(
--tom
