8.7 Starting the Search from a Different Place

A better solution is to tell Perl to search from a different place in the inheritance chain:

 { package Animal;   sub speak {     my $class = shift;     print "a $class goes ", $class->sound, "!\n";   } } { package Mouse;   @ISA = qw(Animal);   sub sound { "squeak" }   sub speak {     my $class = shift;     $class->Animal::speak(@_);     print "[but you can barely hear it!]\n";   } } 

Ahh. As ugly as this is, it works. Using this syntax, start with Animal to find speak and use all of Animal 's inheritance chain if not found immediately. The first parameter is $class (because you're using an arrow again), so the found speak method gets Mouse as its first entry and eventually works its way back to Mouse::sound for the details.

This isn't the best solution, however. You still have to keep the @ISA and the initial search package in sync (changes in one must be considered for changes in the other). Worse, if Mouse had multiple entries in @ISA , you wouldn't necessarily know which one had actually defined speak .

So, is there an even better way?