d2: assigning ranges/iterators to array slices

Posted by modchan on Stack Overflow See other posts from Stack Overflow or by modchan
Published on 2012-03-29T22:26:30Z Indexed on 2012/03/29 23:28 UTC
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ranges

Consider following code:

enum size = 16;
double[size] arr1 = [...];
double[size] arr2 = [...];
process = (double x) { return (x + 1); };

arr2[] = map!(process)(arr1[]); // here

I have trouble converting results of map back to my plain array. Problem applies not only to map, but also to take, repeat and all those fine tools from std.algorithm and std.range that operate on ranges.

On this assignment, I get Error: cannot implicitly convert expression (map(arr1[])) of type Result to double[]. How can I evaluate range to array without using

uint i = 0;
foreach (x; map!(process)(arr1[])) {
    arr2[i] = x;
    i++;
}

?

Additionally, can someone please explain, why I must call map!(process)(arr1[]) instead of map!(process)(arr1) with static arrays? Shouldn't static arrays be compatible with dynamic for means of iteration, or I don't get something?

Also, it seems that straightforward enumeration syntax foreach (index, item; sequence) does not work for ranges - are there workarounds? I guess the reason is the same as why ranges cannot be assigned to array slices.

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