There are safer way to use eval, or even avoid it all together

The Perl Regex Tester

Re^3: My Favourite Regex Tools (Was: Parsing a Variable Format String)

String::Interpolate::RE

It can be as simple as

use String::Interpolate::RE qw( strinterp );
print Substitution(
    "input string",
    "pattern",
    "replacement",
    "flags" );
sub Substitution {
    my( $in, $re, $rep, $flags ) = @_;
    my $global  =  $flags =~ m{g}i;
    my $qrFlags =  join '', $flags =~ m{[msixpodualn]}i;
    $qrFlags = "(?$qrFlags)";
    $re = qr{$qrFlags$re};
    if( $global ){
         $in =~ s{$re}{
           Replace($rep, \%+,{1=>$1,2=>$2,3=>$3});
         }gex;
    } else {
         $in =~ s{$re}{
           my $vars = {
               %+, 1=>$1, 2=>$2, 3=>$3,
           };
           strinterp( $rep, $vars );
         }ex;
    }
}
sub Replace {
    my( $rep, $named, $numed ) = @_;
    my $vars = { %$named, %$numed, 'bananas','bananas' );
    return strinterp( $rep, $vars );
}

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In reply to Re^2: Passing a regex from a CGI HTML form (user supplied regex substitution without eval) by Anonymous Monk
in thread Passing a regex from a CGI HTML form by Linicks

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