Messages in this thread | | | Date | Mon, 20 Aug 2007 14:44:47 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: [PATCH] Make checkpatch rant about trailing ; at the end of "if" expr |
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On Aug 20 2007 13:52, Bodo Eggert wrote: >> But. The above regex does not seem to handle >> >> if ((a = b)); >> oops; >> >> I have tried to come up with a superduper regex that handles multiple >> (), but my regex fu seems to stop above two pairs of (). > >This is because you can't do that using finite regular expressions. > >Regular expressions are Type-3 grammars, but you'd need a Type-2 >grammar to express the Dyck language (and you need to parse a Dyck >Language, ignoring the non-dyck-parts).
So what about this then...
$s = shift @ARGV; $r = qr/a(??{ $r })?b/; if ($s =~ /^$r$/) { print "Yup, that's good\n"; } else { print "fail\n"; }
$ perl foo.pl aabbbb Not so much $ perl foo.pl aaaabbbb Yup, that's good $ perl foo.pl aaaaabbbb Not so much
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Jan --
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