You can pass any Perl source code in the above snippet (which is why it's potentially dangerous).

One templating system would be the Template Toolkit.

use Template;

sub foo {
   my $template = Template->new();

   (my $text = $_[0]) =~ s/$_[1]/
      my $output = '';
      my @matches =
         map { substr($text, $-[$_], $+[$_] - $-[$_]) } 1 .. $#-;
      $template->process(\$_[2], { matches => \@matches }, \$output);
      $output
   /e;
   print $text;
}

foo("This is test 1\n", qr/test (.*)/, 'fish [% matches.1 %]');
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(Untested)