libregexp-assemble-perl 0.34-5 (i386 binary) in ubuntu oneiric

 Regexp::Assemble takes an arbitrary number of regular expressions
 and assembles them into a single regular expression (or RE) that
 matches all that the individual REs match.
 .
 As a result, instead of having a large list of expressions to loop
 over, a target string only needs to be tested against one expression.
 This is interesting when you have several thousand patterns to deal
 with. Serious effort is made to produce the smallest pattern possible.
 .
 It is also possible to track the original patterns, so that you can
 determine which, among the source patterns that form the assembled
 pattern, was the one that caused the match to occur.
 .
 You should realise that large numbers of alternations are processed
 in perl's regular expression engine in O(n) time, not O(1). If you
 are still having performance problems, you should look at using a
 trie. Note that Perl's own regular expression engine will implement
 trie optimisations in perl 5.10 (they are already available in
 perl 5.9.3 if you want to try them out). Regexp::Assemble will
 do the right thing when it knows it's running on a trie'd perl.
 (At least in some version after this one).