extended foreach?

[Daniel Keep]

Mandel wrote:
> Hi,
> 
> I like to know if this feature request is even feasible
> and what others think of it, of course.
> 
> class Foo {
>    int opApply(int delegate(ref Type [, ...]) dg, float f, char[] s) {
>        /*...*/
>    }
> }
> 
> float f = 1.5;
> char[] s = "abc";
> foreach(x; xs; foo; f, s)
> {
> 
> }
> 
> The idea is to pass additional values from foreach to opApply.
> Would be great to filter values in opApply for example.
> (or even chaining foreach in opApply...)

Usually, this is done by having a member function that returns a struct
(or class instance) that has an opApply on it.  For instace:

class Foo {
    struct FooIter {
        float f;
        char[] s;
        int opApply(int delegate(ref Type [, ...]) dg) { /* ... */ }
    }
    FooIter myIter(float f, char[] s) {
        return FooIter(f,s);
    }
}

float f = 1.5;
char[] s = "abc";
foreach(x, xs; foo.myIter(f, s))
{
}

-- 
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{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

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