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Postings from April 2003
Austin Hastings wrote:
>> method foo($self, Point $p :) {...}
>> method foo($self, int $x, int $y :) {...}
>
>
> As A6 currently stands, that won't work -- only multi's are capable of
> having multiple invocants:
>
> multi foo(Foo $self, Point $p) {...}
> multi foo(Foo $self, int $x, int $y) {...} # No colon means invoke ALL
Correct.
You can have two or more multimethod variants of a given name, but only one
method of a given name (in a given namespace).
>>Or are method variants different from multimethod variants?
Yes. The former don't exist. ;-)
Just to clarify:
* Methods have exactly one invocant, and are dispatched solely on the
basis of the run-time type of that invocant.
* Multimethods can have one or more invocants, and are dispatched
solely on the basis of the run-time types of all their invocants.
* Both methods and multimethods can also have non-invocant parameters
(declared after the colon), but the corresponding arguments take no
part in the dispatch process.
Thus calls to the multimethod &foo:
multi foo(Window $w, Event $e : Mode $m) {...}
multi foo(Window $w, Str $e_name : Lode $l) {...}
multi foo(Str $w_name, Event $e : Wode $w) {...}
only consider their first two arguments when selecting which variant to invoke.
Damian
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