note martin Just for completeness, try this one, too: <code> martin => sub { # args: sentence, wantedchars '' eq $_[1] || '' ne $_[0] && $_[1] =~ /^[\Q$_[0]\E]*\z/; }, </code> Putting the whole sentence into a character class will kind of suck with veeery long sentences but medium-sized cases should benefit from the one-pass approach. <p> <i>Update: fixed the order of subroutine parameters</i> 707621 707621