If it was designed into the language from the ground up, as it is (at least to some extent) with Perl 6, then it is a reasonable thing to implement.

Trying to retrofit it to Perl 5 would be near impossible.

The best you could hope to do is use something like Moose to define your own classes for all the basic types, and then write all your programs completely in terms of those constructed types eshewing all of Perl's built-in types and libraries. Besides all the work that would entail--are you up for it to get what you want?--you wouldn't like the results.

And what would it leave you? It wouldn't be Perl. So why use Perl to program in a different language very, very slowly?