FAQ

Thomas Wittek writes:
Steffen Schwigon schrieb:
At least the many keywords seem to be necessary to map the complexity
of different paradigms possible in Perl6. Multimethods are not just
overloading as in C++. Second, the different keywords declare
different behaviour you can choose. Just read S06, it's explained
quite understandable.
Hm, but wouldn't whose be equivalent?

sub foo ($bar) {
$bar.say;
}

multi sub foo ($bar) {
$bar.say;
}

Aren't subs a subset of multi subs, meaning that every sub can be
expressed as a multi sub?
Is there anything a sub has in advantage of a multi sub?
So might not just every sub be a multi sub?
If the only difference is, that you _must not_ declare a sub twice with
different argument lists, I think that this one is relatively
unimportant and letting every sub be a multi sub seems to be more
consistent to me in opposite to this arbitrary looking distinction.

Maybe I just phenomenally misunderstood multi subs, but unless I
did, I can't see why we want to have subs when we can have multi
subs that can do the same and even more.
I understand your point and I confess I'm not sure.

At least there seems to be a visibility difference. In S12 I found
those two sentences:

1. [sub (or method) without a multi] [...] Only one such sub (or
method) can inhabit a given namespace, and it hides any outer subs
(or less-derived methods) of the same short name.

2. [subs or methods declared multi] [...] It does not hide any
routines with the same short name but a different long name. In
other words, multis with the same short name can come from several
different namespaces provided their long names differ and their
short names aren't hidden by a non-multi declaration in some
intermediate scope.


GreetinX
Steffen
--
Steffen Schwigon <schwigon@webit.de>
Dresden Perl Mongers <http://dresden-pm.org/>

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postedJun 21, '06 at 2:41p
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