Treating a slice as an InputRange

[unleashy]

Thanks for the insights everyone, it really helped!

I actually discovered that it wasn't working because one of the 
parsing functions used `std.range.take` and, since I was giving 
it a slice, `take` decided to save the fwdrange instead of 
mutating it. I realised the `take` call was 100% useless, so I 
removed it and it works perfectly now, and refactored to be more 
idiomatic :)

On Wednesday, 15 November 2017 at 21:02:35 UTC, Jonathan M Davis 
wrote:
> If you specifically want a function to accept a range and 
> mutate it without returning it, then it should take its 
> argument by ref. Having it take auto ref is actually quite odd, 
> since that means that the behavior can depend on whether an 
> lvalue or rvalue is passed in.

I was under the impression that templated parameters needed `auto 
ref` to work as `ref` properly. Good to know that's not true.

On Wednesday, 15 November 2017 at 21:11:16 UTC, Steven 
Schveighoffer wrote:
>I'd model your functions after the std.conv.parse functions:
>
>https://dlang.org/phobos/std_conv.html#parse
>
>This always takes the range by reference, and takes the type to 
>parse via a template parameter (more idiomatic D to have 
>parse!int than parseInt).

Yes, that is much more idiomatic than what I was going for. I've 
been writing some Java, so I guess it got to my head :)

On Wednesday, 15 November 2017 at 21:14:04 UTC, Ali Çehreli wrote:
>That should work:
>
>import std.range;
>
>T read(T, Range)(auto ref Range range) if (isInputRange!Range) {
>    range.popFront();
>    return 42;
>}
>
>unittest {
>    ubyte[] slice = [ 1, 2 ];
>    read!int(slice);
>    assert(slice == [2]);
>}
>
>void main() {
>}

That is exactly what I was looking for, thanks!