On 9/3/2016 3:51 AM, Timon Gehr wrote:
I don't think it is a template issue. It's a name lookup issue.
It's both. ADL is mostly useless outside of generic code.
It was initially justified as a solution for operator overloading, which has no
necessary relationship to templates or generic programming.
It's mostly about how
templates specify what interface they require and how the requirements are
satisfied by the caller. ADL is a workaround for the lack of a convenient enough
such protocol in templates. Other approaches to generics solve this particular
issue quite elegantly. (E.g. type classes implicitly pass along the required
free-function functionality.) D's templates don't, this is why it is a template
issue.
By default, name lookup does not work in a way that would allow you to actually
extend types using UFCS, and therefore none of Phobos works that way.
Lambdas!
(Besides, I showed how other scopes can be imported based on a type, and then
things can be looked up in those scopes, and UFCS applied.)
There's LINQ in C#, for example.
C# does not have templates.
It has generics:
https://msdn.microsoft.com/en-us/library/512aeb7t.aspx
and iterators and algorithms and LINQ.
