Actually, regex::assemble would help!

I posted earlier that regex::assemble wouldn't help with your problem, because it's "regex or" not "regex and". But it now occurs to me that in your particular situation, it might help -- efficiency wise. Because you are looking for a regex that does not match several regexes. And actually, in boolean logic that is the same as a does not match "regex1 or regex 2 or regex3". So before you wound up with something like

(?!regex1)(?!regex2)(?!regex3)
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But you could use regex::assemble to do

my $andedRegexes = Regexp::Assemble->new;
  $andedRegexes->add( 'regex1' );
  $andedRegexes->add( 'regex2' );
  $andedRegexes->add( 'regex3' );
#regex is now 'regex(1|2|3)'
#which is more efficient
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and then do a negative lookahead on that. I'm not sure of the quoting syntax here though.

$negatedAndedRegexes = (?=qr($andedRegexes))
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Actually I'm pretty sure that's wrong syntax. But you get the idea.

(Could someone correct that?)

Hope this helps!

Thomas.

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Re: Actually, regex::assemble would help! by ady (Deacon) on Dec 04, 2004 at 12:56 UTC
Yes Thomas, if i chose to open the source and recode the parser, i could walk down that road. However my situation is more like (as pointed out by eyepopslikeamosquito above) the Perl Cookbok 6.18 : `"... So you need to write a single pattern that matches either of two diffe +rent patterns (the "or" case) or both of two patterns (the "and" case +) or that reverses the sense of the match ("not"). This situation arises often in configuration files, web forms, or comm +and-line arguments. ..."` [download] So with that i do consider my problem solved, -- even though as it's written in the recipe : `...It's not a pretty picture, and in a regular program, you'd almost n +ever do this"...` [download] Sic! Best Regards / Allan Dystrup `"...this very place is the Land of Lotuses..." / Hakuin Ekaku Zenji` [download]	[reply] [d/l] [select]

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Re: Actually, regex::assemble would help!
by ady (Deacon) on Dec 04, 2004 at 12:56 UTC

However my situation is more like (as pointed out by eyepopslikeamosquito above) the Perl Cookbok 6.18 :

"...
So you need to write a single pattern that matches either of two diffe
+rent patterns (the "or" case) or both of two patterns (the "and" case
+) or that reverses the sense of the match ("not").
This situation arises often in configuration files, web forms, or comm
+and-line arguments.
..."
[download]

So with that i do consider my problem solved, -- even though as it's written in the recipe :

...It's not a pretty picture, and in a regular program, you'd almost n
+ever do this"...
[download]

Sic!

Best Regards / Allan Dystrup

"...this very place is the Land of Lotuses..." / Hakuin Ekaku Zenji
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[reply]
[d/l]
[select]