Interfaces, traits, concepts, and my idea for a DIP

[Tofu Ninja via Digitalmars-d]

On Wednesday, 29 July 2015 at 20:26:53 UTC, Tofu Ninja wrote:
> If you write:
>
> @satisfies!(isInputRange, MyRange) struct MyRange { ... }
>
> the UDA can check it self, it really works as expected. Which 
> is why I suggested a way to get whatever the UDA is attached to 
> automatically in my other post.

A UDA can reference the thing it's being attached to with no 
problems.
For example, this works 100% as expected right now...

@UDA!testS struct testS // UDA fails to instantiate because testS 
is not an inputRange!
{
	
}

template UDA(alias a)
{
	import std.range;
	static assert(isInputRange!a);
}

The only thing that would be needed to make this a nice solution 
is some syntax sugar to automatically get whatever the UDA is 
attached to, which is why I suggested this:

template UDA(alias a = __UDA_ATTACHMENT__) { ... }