Perl is fairly good at compiling regexps, and provided you
only use the constructs that can be simulated with a
'standard' regexp (which is to say, provided you can
construct a deterministic finite automata from the expression),
the running time should be O(n), where n is the length of
the string being matched against.
This means you should avoid using anything that might cause
perl to backtrack or lookahead - mostly that means the
(?...) operators.
Anyhow, from your example, it looks like the closing quote
is always the last one, so you could just take advantage of
perl's greediness and use the following regexp, which
should run at exactly the same speed as your original:
/^(\S+).*?\[(\S+).*?] (\S+) "(.+)" (\d+)/
Andrew.
