A Briefer Syntax for Using Concepts

[Sergei Nosov via Digitalmars-d]

On Wednesday, 7 May 2014 at 11:57:51 UTC, w0rp wrote:
> Here is a question, is it possible for D, or any future 
> language, to eventually take something like this...
>
> void foo(InputRange)(InputRange range) 
> if(isInputRange!InputRange);
>
> ...and to instead be able to write it like this?
>
> void foo(InputRange range);
>
> Where the latter expands into something like the former, and 
> InputRange is not a type. How to declare such a thing in the 
> first place doesn't matter that much. There are many ways that 
> could be done. I'm just wondering if the above is possible at 
> all.

C++ concepts has similar syntax. 
http://isocpp.org/blog/2013/02/concepts-lite-constraining-templates-with-predicates-andrew-sutton-bjarne-s

template<Sortable Cont>
void sort(Cont& container);

I don't think making InputRange behave as you suggest in void 
foo(InputRange range); is a valid options, since - how do you 
handle the situation when you want to accept 2 InputRanges of 
possibly distinct types?

void foo(InputRange range1, InputRange range2); // how to specify 
that InputRange should be exactly the same type? or possibly 
distinct types?