What is "FilterResult" type?

[Atila Neves via Digitalmars-d-learn]

On Wednesday, 9 September 2015 at 07:19:06 UTC, Bahman Movaqar 
wrote:
> On Tuesday, 8 September 2015 at 18:45:33 UTC, Jonathan M Davis 
> wrote:
>> If you're returning a range, you should be returning auto.
>
> @Jonathan, @cym13 and @Meta
> It's reasonable to use `auto`.  However there are times when 
> you need to pass the `auto` value to another function and the 
> receiving function needs to know the type of its input 
> arguments.

No, it doesn't. It needs to know what the compile-time interface 
is, i.e. what it can do with that type. If the type in question 
happens to be an InputRange, then the consumer function would be:

void func(R)(R range) if(isInputRange!R) { ... }

instead of using a concrete type like this:

void func(MyType range) { ... }

That way you can change range types and `func` doesn't care.

Atila