my %dict = ( SENTENCE => ["NP VP"], NP => ["ART NOUN"], VP => ["VERB NP"], ART => [qw/ the a /], NOUN => [qw/ man ball woman table /], VERB => [qw/ hit took saw liked /] ); sub rand_production { my $items = $dict{+shift}; return $items->[rand @$items]; } sub generate { local $_ = shift; my $nonterminal = join "|", map quotemeta, keys %dict; 1 while s/($nonterminal)/ rand_production($1) /e; return $_; } print generate("SENTENCE"), $/;