Re: Using constants in regexes?

in reply to Using constants in regexes?

There's a few ways of tackling this problem, depending on your goals. To use a constant as an interpolated value within a regular expression, use the following notation:

if ($string =~ /${\(TEST)}/) {
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This has the unfortunate consequence of slowing down your regular expression, since it can't be compiled. Using the qr operator is your best bet. You can use japhy's suggested format:

use constant PATTERN => qr/def/;
if ($string =~ PATTERN) { ... }
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An alternative is to leave the constant in string format, and compile it just prior to executing the regex:

use constant PATTERN => 'def';
my $regex = qr/${\(PATTERN)}/; #options such as /m can go here.
if ($string =~ regex) { ... }
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This gives you the added benefit of being able to easily print the regex out for debugging purposes.

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