Compile-Time Interfaces (Concepts)

[Atila Neves via Digitalmars-d-learn]

On Thursday, 17 July 2014 at 22:52:37 UTC, Justin Whear wrote:
> On Thu, 17 Jul 2014 22:49:30 +0000, Nordlöw wrote:
>
>> AFAIK there is no compile-time variant of interfaces right?
>> 
>> Why is that?
>> 
>> Wouldn't it be nice to say something like
>> 
>>      struct SomeRange realize InputRange {
>>          /* implement members of InputRange */
>>      }
>> 
>> and then the compiler will statically check that that all 
>> members are
>> implemented correctly.
>> 
>> I guess this requires some new syntax to describe what an 
>> InputRange is.
>> 
>> Kind of like C++ Concepts.
>
> What benefits would accrue from adding this?  Static 
> verification that a
> structure implements the specified concepts?  If so, you can 
> simply do
> this instead:
>
> static assert(isInputRange!SomeRange);

This is sufficient, but not adequate. Just as the built-in
unittest blocks with assertions, it's great when the assertion is
true but good luck finding out where the bug is when it's not.

The D Cookbook has an idiom to handle this by checking for __ctfe
but it's super hacky and there should be a better way.

I have lost count of how many times I wish the compiler would
help me with compile time interfaces as it does with runtime
code. static override and static interface? Yes please.

Atila