nope, you wouldn't benefit from an /o in this case..

qr quotes and compiles the pattern as a regular expression. To see what it's doing, try this:

perl -e 'my $re = qr!yes|no!; print "$re\n";'
prints: (?-xism:yes|no)

[download]

The result of qr, in this case $re, can be used on it's own, or within another regex.

my $re = qr!yes|no!;
print "yes or no!\n" if "yes" =~ $re;
print "yes or no only" if "maybe" !~ $re;
print "polite yes or no\n" if "yes thankyou" =~ /$re thankyou/;

[download]

The first 2 uses in this code will not trigger the recompling of any regex. The 3rd will need to be compiled, although I believe you could do...

my $re = qr!yes|no!;
my $re2 = qr!\sthankyou!;
print "yes or no!\n" if "yes" =~ $re;
print "yes or no only" if "maybe" !~ $re;
print "polite yes or no\n" if "yes thankyou" =~ /$re$re2/;

[download]

..and avoid any recompilation after the initial qr's

cheers,

J

In reply to Re: Re: Re: regex "o" modifier by edoc
in thread regex "o" modifier by shemp

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