Pseudohashes

The key idea

For 5.005 (1998), someone had an interesting idea:

Suppose Critter objects are based on arrays instead of hashes

And suppose Critter.pm declared its fields at compile time:

        package Critter;
        use fields qw(NAME TYPE size hearts likes_cookies 
                      ...
                      pelagic tentacles is_tasty 
                      ...
                      );

And suppose Perl knows that $self will hold a Critter object

        my Critter $self;