@matches = f("____", \@dict);  # @matches would be every 4 letter word in @dict
@matches = f("__rl", \@dict);  # @matches could include 'earl', 'perl', 'curl', etc.

##</code><code>##

$string = "s__s";
@letters_guessed = qw( s e );
@possible_words = qw( suns sets sees saws skis sews sits );

$guess = g( $string, \@possible_words, @letters_guessed );