my %dispatch=(
   A=>sub { split(/!/,$$_[0]); },
   ... 
); 

sub dispatch {
   my $x=$letters[random($nLetters)];
   my $y='xyzzy!' x random(1000);
   if (exists $dispatch{$x}) {
      $dispatch{$x}->(\$y);
   } else {
      warn "Huh?";
   } 
}