On Wednesday, 25 March 2015 at 08:55:14 UTC, bearophile wrote:
matovitch:
I am curious to know how isInputRange is implemented since I
wanted to do kind of the same but I am afraid it's full of
(ugly)
traits and template trickeries where haskell type classes are
quite neat and essentially a declaration of an interface.
Take a look at the sources and learn. They are sometimes tricky
to get right, but it's not a problem of ugly syntax.
I wondered if you could check statically that the type could
implement an interface *if it wanted to* that is, without
inheriting it...
Template constraints don't require inheritance.
Bye,
bearophile
Yes I know that you don't need to inherit some InputRange
interface to be able to check a user defined type is an input
range. And template constraints are more powerful/general than
type classes but it's harder to get right for the beginner. I
will definetly look at the code anyway.
I was looking at :
interface IInputRange(InputRange) {...}
class TypeClass(T,I) : I!T
{
alias t this;
T t;
}
void foo(InputRange) (InputRange inputRange) if
(isInstanciable(TypeClass!(InputRange, IInputRange)));
