Use variable as a regex modifier in perl

Question

Looking for a way to pass modifier from perl variable. for e.g.

sub isContentValid
{
   my $modifier = shift;
   my $validationRe = shift;

   $modifier = ($modifier) ? "" : "i";
   $isValid = $ans =~ /$validationRe/$modifier;
   return $isValid;
}

Answer 1

You may use modifiers inside regular expression.

man perlre

The modifiers "/imsxadlup" may also be embedded within the regular expression itself using the "(?...)" construct, see "Extended Patterns" below.

sub isContentValid
{
   my $modifier = shift;
   my $validationRe = shift;

   $modifier = ($modifier) ? "-i" : "i";
   $isValid = $ans =~ /(?$modifier)$validationRe/;
   return $isValid;
}