my %backrefs;
      my( @backrefs ) = $with =~ /\$(\d+)/g;
      if ($modifiers =~ /g/) {
          $value =~ s/$this/
                        no strict 'refs';
                        @backrefs{@backrefs} = map { ${$_} } @backrefs;
                        my $ret = $with;
                        $ret =~ s'\$(\d+)'$backrefs{$1}'g;
                        undef %backrefs;
                        $ret; 
                    /ge;
      } else {
...