On Mon, Nov 07, 2005 at 08:44:28PM +0100, TSa wrote:
: HaloO,
:
: Larry Wall wrote:
: > : ::Takes3Ints ::= :(Int,Int,Int --> Any);
: > :
: > : my &foo:(Takes3Ints);
: >
: > I'd say that has to be something like:
: >
: > my &foo:(Takes3Ints:);
: >
: > or maybe one of
: >
: > my &foo:(Takes3Ints \!);
: > my &foo:(\Takes3Ints);
: > my &foo\(Takes3Ints);
: >
: > since Takes3Ints is the implementation and/or arglist type.
:
: Sorry, you lost me. Why is there a invocant colon in the
: first example,
It would presumably indicate an implementation type for &foo, which
is probably wrong.
: and what exactly does the ref indicator
: mean in all the three different alternatives?
Those would indicate an arglist parameter, which is probably right.
The most recent S06 has
sub foo (\$arglist)
to bind the entire arglist object to $arglist, though arguably (no pun
intended) the syntax could be:
sub foo \($arglist)
instead. This goes with the decision that rvalue \(1,2,3,:foo)
generates an arglist object.
: > Otherwise how do you distinguish
: >
: > my &foo:(Takes3Ints);
: > my &foo:(Int, Int, Int);
:
: You mean the latter &foo as non-code, simple 3-tuple type?
: Otherwise I would think the & sigil implies the optional
: default &:( --> Any).
The Any would be implied in that case. I don't see much difference between
that and the multi disambiguating construct:
my &foo := &bar:(Int, Int, Int);
say foo(1,1,1);
: But than again I haven't fully grasped
: your notion of the pure type name before the first colon.
I was just playing off of your @array:(Array: ...) thought, but the
signature is not the implementation type, so forget that.
: > The colon would still be required in an rvalue context. But the extension
: > of that to subs seems to be:
: >
: > my &sub(Sub: \$args)
: >
: > Hmm, does that mean that a method actually looks like this?
: >
: > my &meth(Method: $self: \$args)
:
: I have ranted that I see method invocation as a two step
: call with a covariant dispatch first and then a normal
: contravariant call with argument type check, but why the
: second colon?
Only because multiple colons imply tiebreaking behavior under MMD.
I'm just trying to picture SMD as a form of MMD.
: And why the first on &sub(Sub: \$args)? Just
: to name the intended code subtype?
Yes, just the same as your @array:(FooArray: ...) idea that the first
invocant is the function-like object implementing the thing.
Larry
