On Saturday, 10 August 2013 at 18:28:41 UTC, Simen Kjaeraas wrote:
On 2013-08-10, 14:58, JS wrote:
e.g.,
interface A
{
static T A(T)() { ... }
}
can be used as A!T instead of A.A!T. Same for classes and
structs. If you want a use case I'm not going to stop you from
coming up with one... so feel free.
Tried with DMD 2.063.2, and I'm unable to make A!T compile. Are
you sure
you've written the code you intended to?
For reference, this is the code I tried:
interface A {
static T A(T)() {
return T.init;
}
}
void main() {
A!int a; // Error: template instance A!(int) A is
not a template declaration, it is a interface
auto b = A!int; // Error: template instance A!(int) A is
not a template declaration, it is a interface
}
This code, of course, works:
template A(T) {
interface A {
}
}
void main() {
A!int a;
}
No, the code does not compile as it is a proposal.
The issue is simple to allow interfaces to have Eponymous static
members. This makes it easier to use in some cases. Your template
example just creates a template... but does nothing as far as
inheritance.
interface iFactory(A)
{
static A iFactory(Args...)(Args args) { return new A; }
// ....
}
class Q : iFactory!Q
{
// ....
}
auto q = iFactory!Q();
instead of
auto q = iFactory!Q.iFactory();
or
auto q = Q.iFactory()
The last case being only acceptable if Q inherits from
iFactory(which it may not).
This is simply generalizing eponymous templates to interfaces,
classes, structs, etc.
