On Wednesday, 20 July 2016 at 05:54:41 UTC, mogu wrote:
On Wednesday, 20 July 2016 at 01:50:37 UTC, Adam D. Ruppe wrote:
On Wednesday, 20 July 2016 at 01:14:05 UTC, mogu wrote:
Why S's type isn't something like `S: (T) -> S`?
Because S isn't a type... think of a template as being like a
function that returns a type.
int foo(int) { return 0; }
There, you wouldn't expect typeof(foo) to be int, no,
typeof(foo) is a function that returns an int.
The template is the same thing - it isn't a type, it is a
template that returns a type.
So it's a higher kinded type aka type class in Haskell. But D's
reflection cannot get enough information about template's kind.
Only a `void` given. It may be inconvenient in distinction
between an alias of template and void. The only solution AFAIK
is by string of the type property .stringof.
Note that void is a type, while S is not. So you can do:
assert(is(void)) // is(type) returns true
assert(!is(S)) // is(template) returns false;
