Size Limit on {MIN,MAX} Regex Quantifier?

chakram88 has asked for the wisdom of the Perl Monks concerning the following question:

Oh Enlighted Ones:

I have dutifully super-searched to no avail, and I humbly ask your guidance.

I'm not sure if this is an undocumented feature, or if there is a purpose for it. (or perhaps documented where I have been unable to locate it).

Apparently there is an upper limit of '32766' on the MAX value of the regex {MIN,MAX} quantifier. I discovered this by way of the Data::FormValidator max_length constraint.

Observe:

#!/usr/bin/perl -lw

my $max = 32767;
my $value = "feeefooobarrr";

my $match = ($value =~ /^(.{0,$max})$/);

print $match;
[download]

produces the following error:

Quantifier in {,} bigger than 32766 in regex; 
marked by <-- HERE in m/^(.{ <-- HERE 0,32767})$/
[download]

Has anyone come across this upper limit before? Am I missing documentation surrounding this? Is it too obscure to worry about?

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Re: Size Limit on {MIN,MAX} Regex Quantifier? by FunkyMonk (Bishop) on Nov 05, 2007 at 19:55 UTC
It's documented in perlre, just below here	[reply] [d/l] [select]
Re^2: Size Limit on {MIN,MAX} Regex Quantifier? by chakram88 (Pilgrim) on Nov 05, 2007 at 20:12 UTC
grrrr. Thank you FunkyMonk. I'm off to do my due penance for not carefully reading the response to `perldoc perlre` I rely too much it seems on The Camel. <sigh>	[reply] [d/l]
Re: Size Limit on {MIN,MAX} Regex Quantifier? by grinder (Bishop) on Nov 05, 2007 at 21:28 UTC
Is your regexp exceptionally intricate and detailed, and your code is a cut-down example, or are you really just trying to match anything (dot). If it's the latter case, then a regexp is not the right way to go about solving the problem. Better to: `my $len = length $value; if ($len < $min or $len > $max) { panic(); } else { ok(); }` [download] Internally, perl keeps track of string length at all times, so calling length is a very cheap operation, whereas it is quite possible that the regexp engine has to scan through the whole string to satisfy the curly. • another intruder with the mooring in the heart of the Perl	[reply] [d/l]