I can use the ElementType() template in the std.rane library to find the type of the elements of a range,isn't it? But I cant compile the following programme.

I get a "untitled.d(32): Error: template instance ElementType!(listR) does not
match template declaration ElementType(R)" error.

What could be the problem ?
--------------------------------------------------------------------------

import std.stdio;
import std.range;
import std.container;

int main(char[][] args)
{
	auto list=SList!(int)(1,2,3);
	auto listR=list.opSlice();
	writefln("%s",ElementType!(listR));


	return 0;
}
--------------------------------------------------------------

Thank you...!

>
> I get a "untitled.d(32): Error: template instance ElementType!(listR) does not
> match template declaration ElementType(R)" error.
>
> What could be the problem ?
> --------------------------------------------------------------------------
>
> import std.stdio;
> import std.range;
> import std.container;
>
> int main(char[][] args)
> {
>        auto list=SList!(int)(1,2,3);
>        auto listR=list.opSlice();
>        writefln("%s",ElementType!(listR));
>
>
>        return 0;
> }
> --------------------------------------------------------------

ElementType acts on types. It takes a type and 'returns' (compiles to,
actually) another type. You need to give it typeof(listR).
Then, as ElementType!(typeof(listR)) is a type, you cannot pass it to
writeln. Use .stringof to go from the type to a string representation
of its name.

So:

writefln("%s", ElementType!(typeof(listR)).stringof);

ElementType!(typeof(listR)) is a type like any other. You can create a
variable with it:

ElementType!(typeof(listR)) elem;

Btw, .opSlice() is the name of the '[]' operator. You previous line
can be written like this:

auto listR = list[];


    Philippe

--Philippe wrote::

>ElementType acts on types. It takes a type and 'returns' (compiles to,
>actually) another type. You need to give it typeof(listR).
>Then, as ElementType!(typeof(listR)) is a type, you cannot pass it to
>writeln. Use .stringof to go from the type to a string representation
>of its name.
>
>So:
>
>writefln("%s", ElementType!(typeof(listR)).stringof);
>
>ElementType!(typeof(listR)) is a type like any other. You can create a
>variable with it:
>
>ElementType!(typeof(listR)) elem;
>

Got it!. Thanks.

I faced this confusion because of the description for "ElementType" which is available in http://d-programming-language.org/phobos/std_range.html. It says,

"
template ElementType(R):

The element type of R. R does not have to be a range. The element type is determined as the type yielded by r.front for an object r or type R. For example, ElementType!(T[]) is T. If R is not a range, ElementType!R is void.

"
So I thought that just passing ElementType!listR was adequate. :s