There is not a noticeable increase in speed in using
$x = qr/.../; /$x/ instead of
$x = '...'; /$x/o; in the testing I have done. And the
/o modifier is ONLY useful if the regex has any variables in it.
The place where qr// is important is when looping over strings and patterns. If you do a benchmark of code like this:
while (<>) {
for my $p (qr/a+b/, qr/c+d/, qr/e+f/) { foo() if /$p/ }
}
# vs.
while (<>) {
for my $s ('a+b', 'c+d', 'e+f') { foo() if /$s/ }
}
The
qr// version will be considerably faster because Perl knows the regexes are already compiled, whereas in the string version, we need to compile three regexes for every line of input.
_____________________________________________________
Jeff[japhy]Pinyan:
Perl,
regex,
and perl
hacker, who'd like a job (NYC-area)
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;
