my @words = ("while", "foreach", "loop");
         foreach my $word (@words) {
            my $word_len = length $word;
            my $next = "1.0";
            while (my $from = $t->search(-regexp, "\\b$word\\b", $next, "end")) {
               $next = "$from + $word_len chars";
               $t->tagAdd("green", $from, $next);
               $t->tagAdd("bold", $from, $next);
            }
         }