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On Sat, Jul 16, 2005 at 19:02:49 -0600, Luke Palmer wrote:
> I'm going to have some coffee mugs thrown at me for saying this, but perhaps:
>               Generic     String    Numeric    Identity
>            +-----------+---------------+----------------+---------------+
> Equality   |    ==     |      =~=      |       =+=      |   =:=         |
>            +-----------+---------------+----------------+---------------+
> Comparison | > < >= <= | ~> ~< ~>= ~<= | +> <+ +<= +>=  | $ < $ |
>            +-----------+---------------+----------------+---------------+AA

I have another view.

The Num role and the Str role both consume the Eq role. When your
class tries to both be a Num and a Str, == conflicts.

I have two scenarios:

        class Moose does Num does Str { ... }

        # Moose was populated with:
        multi method infix:<==> (Moose does Num, Moose does Num) { ... }
        multi method infix:<==> (Moose does Str, Moose does Str) { ... }


        # Str and Num try to add the same short name, and a class
        # composition error happenns at compile time.

Recently I discussed MMD with chromatic, and he mentioned two things
that were very important, in my opinin:

        * The Liskov substitution principal sort of means that MMD
          between two competing superclasses, no matter how far, is

        * Coercion of parameters and a class's willingness to coerce
          into something is a better metric of distance

Under these rules the way this would be disambiguated is one of:

        - Moose provided it's own infix:<==>
        - Moose said which <==> it prefers, Num or Str. A syntax:

                multi method infix:<==> from Str;

          (this could also be used for importing just part of a

> All in all, generic equality and comparison is something that Perl 5
> did really poorly.  Some people overloaded eq, some overloaded ==,
> some wrote a ->equal method, and there was no way to shift between the
> different paradigms smoothly.  This is one of the times where we have
> to choose for them.

I wholly agree

 ()  Yuval Kogman <[EMAIL PROTECTED]> 0xEBD27418  perl hacker &
 /\  kung foo master: /me whallops greyface with a fnord: neeyah!!!!!!!

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