http://www.perlmonks.org?node_id=1179851


in reply to Re: [RFC] Building Regex Alternations Dynamically
in thread Building Regex Alternations Dynamically

Hi LanX,

Thanks for your comments, I'll think about whether I can provide a TL;DR version - my thought was that impatient users could just copy-n-paste my code :-)

IIRC there is a hard limit for the length of a regex-string

I'm not sure, I'll have to look into it, but I do know this works :-)

my $word_regex = do { open my $wfh, '<:utf8', '/usr/share/dict/words' or die $!; chomp( my @words = <$wfh> ); close $wfh; my $re = join '|', map {quotemeta} sort { length $b <=> length $a or $a cmp $b } @words; qr/$re/i }; print length($word_regex), "\n"; __END__ 964836

Thanks,
-- Hauke D

Replies are listed 'Best First'.
Re^3: [RFC] Building Regex Alternations Dynamically
by LanX (Saint) on Jan 18, 2017 at 14:15 UTC
    > > IIRC there is a hard limit for the length of a regex-string

    Maybe not in the string length but for sure in the processing.

    something like /x{33000}/ will result in

    Quantifier in {,} bigger than 32766 in regex; ...

    But that's not exactly relevant for your case :)

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)
    Je suis Charlie!