How to use a variable as modifier in a substitution

Question

Is there a way to use a variable as modifier in a substitution?

my $search = \'looking\';
my $replace = \'\"find: $1 =\"\';
my $modifier = \'ee\';

s/$search         


        

Answer 1

While the method using eval to compile a new substitution is probably the most straightforward, you can create a substitution that is more modular:

use warnings;
use strict;

sub subst {
    my ($search, $replace, $mod) = @_;

    if (my $eval = $mod =~ s/e//g) {
        $replace = qq{'$replace'};
        $replace = "eval($replace)" for 1 .. $eval;
    } else {
        $replace = qq{"$replace"};
    }
    sub {s/(?$mod)$search/$replace/ee}
}

my $sub = subst '(abc)', 'uc $1', 'ise';

local $_ = "my Abc string";

$sub->();

print "$_\n";  # prints "my ABC string"

This is only lightly tested, and it is left as an exercise for the reader to implement other flags like g