On Sun, 12 Dec 2010 20:47:04 +0100
spir <denis.spir@gmail.com> wrote:

> Hello,
> 
> Had a nice time figuring out how to let opApply allow index iteration like:
>     foreach (i, x ; collection) {}
> Finally managed to do it adding 'i' everywhere:
> 
> struct S1 {
>     private int[] elements = [];
>     int opApply (int delegate (ref uint, ref int) block) {
>         foreach (uint i, int n ; this.elements)
>             block(i, n);
>         return 0;
>     }
> }
> 
> Is this the intended idiom?
> Now, I'm trying to make this work with ranges instead (input range only as of now). Seems i'm not smart enough to guess it alone...
> 
> Thank you,
> Denis

PS: Also tried to make iteration work by defining slice "with no argument" (coll[]) only, like indicated in TDPL p.381. But could not manage to do it.

Thank you again,
Denis
-- -- -- -- -- -- --
vit esse estrany ☣

spir.wikidot.com

spir <denis.spir@gmail.com> wrote:

> PS: Also tried to make iteration work by defining slice "with no argument" (coll[]) only, like indicated in TDPL p.381. But could not manage to do it.

The point of coll[] is that a collection may not want to define the
range primitives itself, but rather expose a special range struct for
that purpose:

class Collection {
    auto opSlice( ) {
        struct range {
            // front, popFront, empty, whosYourDaddy
        }
        return range( this );
    }
}

-- 
Simen