Ph. Marek writes:
> Hello everybody,
>
> first of all please forgive me if I'm using the wrong words - I'm not up to
> date about the (current) meanings of methods, functions, etc.
>
>
> I read the article
> http://www.cuj.com/documents/s=8042/cuj0002meyers/
>
> There is stated (short version - read article for details):
> In C++ there are member functions, which are called via
> object.member(parameter),
> and non-member (possibly friend) function, which are called via
> function(object,parameter).
>
> I wondered whether perl6 could do both:
> - When called via object.member, look for a member function; if it is not
> found, look for a function with this name, which takes an object as first
> parameter.
> - When called the other way, look first for the function, then for a member.
Something like this has been decided. It's not quite as permissive as
the scheme you describe. It basically says that:
$foo.member;
Is equivalent to:
member $foo;
If no non-member C<member> has been defined. However, it doesn't go the
other way 'round, because although Perl 6 is adding types, the majority
of programs will remain untyped, and that would get pretty dangerous.
I think single-invocant multimethods are synonymous with real methods.
So C<bar> in:
class Foo {
method bar(Baz $baz) {...}
}
Is used the same was as in:
multi sub bar(Foo $foo: Baz $baz) {...}
Hmm, but if you can use a comma anywhere you can a colon in a
multimethod call, that begs for:
multi sub bar(Foo $foo, Baz $baz) {...}
To be usable as:
$foo.bar($baz) {...}
I think it's a good thing to allow re-factoring of methods out into
multimethods and vice-versa, without changing the calls. Regular subs
shouldn't be able to be called with method syntax, though.
Luke
>
> So both ways are possible, and in the (not-interfering) normal situation (only
> one of member/function defined) it would support encapsulation, in that a
> caller does not need to know if this function was a member or not.
>
>
> I fear that I'm on a completly wrong track, or that this has been decided -
> but I didn't find something about this.
>
>
> Regards,
>
> Phil
>
