HaloO,
Autrijus Tang wrote:
On Mon, Aug 01, 2005 at 03:16:50PM +0200, "TSa (Thomas Sandla�)" wrote:
sub equitype ( ::a $x, a $y) { ... }
That's not a bad idea at all. I rather like it. I'd just still like an
explicit type-unifying parens around ::a, just so people won't say
I try to maintain the 'parens only group' point of view. But it
seems to be violated elsewhere, too.
sub foo (::Int $x) { ... }
and accidentally rebind Int.
Why so shy? It would rebind foo::Int with respect to the inside
of &foo. Of course the funny effect is that for a call foo( "blahh" )
foo::Int means Str :)
I guess this is why $Larry wants a role wrapped around such type parameter
instanciators:
role Foo[::Int] # hides *Int
{
sub foo (Int $x) { ... }
}
and explicit instanciation
use Foo[Int]; # or some such
use Foo[Str];
use Foo[Num];
But I don't know if he also wants to carry that on to the actual calls:
Foo[Int]::foo(42);
Foo[Str]::foo('42');
Foo[Num]::foo(3.14);
OTOH, one has to use *::Int or *Int to surely get the standard Int,
anyway. And for getting guaranteed type locality inside &foo a
sub foo( MY::Int $x ) {...}
might be needed, too. This nicely fits other pseudo namespaces:
sub foo( Int $x ) {...} # whatever Int is in effect
# at compile time
sub foo( ::Int $x ) {...} # deferred lookup to CHECK time
sub foo( MY::Int $x ) {...} # dynamically from $x
sub foo( foo::Int $x ) {...} # same for all invocations? error?
sub foo( OUR::Int $x ) {...} # from package
How usefull OUTER::, CALLER::, etc. are I have no idea. Perhaps it's
a good idea to reserve single capital letter barewords for type params.
Or a twigil if we think of '::' beeing s sigil:
sub foo( ::^a $x ) {...}
This saves one character compared to your (::a) which is the
same length as MY::a.
--
$TSa.greeting := "HaloO"; # mind the echo!
