Re^2: Parse::RandGen::Regexp

[paulski]

This won't work. If the string comes in as "/test/smi" and I simply place the string inside the qr, it breaks. e.g. I'd get qr//test/smi//;, which doesn't help me. I can get rid of the close //'s easily enough but getting the /smi outside the regexp is harder.

[ikegami]

You mean you start with /test/smi from some outside source? The only way to use that is to eval it. Of course, that means using eval on something from an outside source, which is a big no-no.

If the user can only use / as the delimiter, then a simple regexp will process the options:

use strict;
use warnings;

# For example, get regexp from command line:
$regepx = $ARGV[0];

# Look for and remove end slashes and modifiers.
$regexp =~ s{^/}         {} or die("Bad input\n");
$regexp =~ s{/([msix]*)$}{} or die("Bad input\n");

my $modifiers_on  = $1;

my $modifiers_off = join '',
                    grep { index($modifiers_on, $_) < 0 }
                    qw( x i s m );

# Add the modifiers:
$regexp = "(?${modifiers_on}-${modifiers_off}:${regexp})";

# Compile the regexp and check for errors:
$regexp = eval { qr/$regexp/ }
   or die("Bad regexp: $@\n");

# Now you can use it:
print($str =~ $regexp ? 'match' : 'no match', "\n");

It's trickier if you want to support substitutions and the (g)lobal modifier. You're better off asking for these as seperate arguments. (The search string, the replace string and the modifiers.)

[paulski]

Thanks, this is really helpful. :-)

Paul