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

[Sebastiaan Koppe via Digitalmars-d]

On Friday, 31 July 2015 at 14:23:28 UTC, Atila Neves wrote:
> On Friday, 31 July 2015 at 11:16:48 UTC, Biotronic wrote:
>> Why can't another template use the very same concept 
>> information to check if a type implements the concept?
>>
>> e.g.:
>>
>> @satisfies!(myConcept, MyStruct)
>> struct MyStruct { /* ... */ }
>>
>> void foo(T)(T t) if (check!(myConcept, T))
>> { /* ... */ }
>
> Because you want to:
>
> 1. Check your type and get sensible error messages
> 2. Use a constraint in function declarations
>
> It's ok for template constraints to be false without causing a 
> compilation error; that's how we get compile-time template 
> function resolution. When you're using something like 
> `@satisfies` however, you want a compilation error and its 
> message. That's why you need two things.
>
> Atila

He does have a point. isInputRange!Bar = (checkInputRange!Bar == 
true);