A string is a regular expression of sorts, so you could simply extract these from a hash and test against them. However, each time through you will have to recompile the pattern, which can be slow going if you do this a lot. Using the qr operator can help a bit, or using the /o switch to prevent compilation, but you might be better off using a hash of subs which just happen to contain regular expressions.

Here's something that demonstrates my idea: 
my %validate = (
        int  => sub { my($v)=@_; $v=~/^[0-9]+$/; },
        date => sub { my($v)=@_; $v=~/^[12]\d\d\d\-[01]?\d\-[0123]?\d/
+; },
);

foreach my $value (qw [ 24 140 510 2001-04-14 3014-30-55 ])
{
        print "$value\n";
        foreach my $type (sort keys %validate)
        {
                print "\tIs '$type'\n" if ($validate{$type}($value));
        }
}

[download]
If you have many, many different patterns to define, you might want to eval them into the hash, like so: 
$validate{$new_type}
     = eval "sub { my(\$v)=\@_; \$v=~$regex; }";

[download]
Of course, taking special care to ensure $regex was a self-contained regex (i.e. /x/ or !/!) and did not contain anything that was going to be invalid when eval'd, though of course you can always check $@ and see what went wrong.

The advantage to using a full sub over just a regex is that you can validate in a context outside of a regex just to be sure. For example, you could check that the day of the month was actually 31 or less, instead of possibly 39.

In reply to Re: Hash/Array of Regular Expressions? by tadman
in thread Hash/Array of Regular Expressions? by irom

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