Add paragraph for dealing with ovelapping copying; issue #1317

[Infiltrator]

Closes https://d.puremagic.com/issues/show_bug.cgi?id=1317

[andralex]

"hit" is duplicated

[Infiltrator]

Good catch.

[ghost]

Shouldn't we have some library functionality with which we can effectively do s[0] = s[1]; s[1] = s[2]; with a single call?

[andralex]

remove?

[ghost]

I think it's copy :

import std.algorithm;

void main()
{
    {
        int[] s = [1, 2, 3, 4, 5];
        s[1..3].copy(s[0..2]);
        assert(s == [2, 3, 3, 4, 5]);
    }
    {
        int[] s = [1, 2, 3, 4, 5];
        s[0..2] = s[1..3].dup;
        assert(s == [2, 3, 3, 4, 5]);
    }
}

This should avoid .dup's memory allocation.

[andralex]

Nice. Remove would do this:

        int[] s = [1, 2, 3, 4, 5];
        s = s.remove(0);
        assert(s == [2, 3, 4, 5]);

[dnadlinger]

Yep, encouraging the use of dup here is a bad idea, as it is suicide performance-wise. I'd just make it say something along the lines of »use an element-wise copy«, maybe with a reference to std.algorithm.copy in parens.

[andralex]

Anyhow @Infiltrator could you please amend the example to avoid dup?

[quickfur]

ping
Any updates since last comments?

[ghost]

Looks like not. Can anyone else take this over?

[ntrel]

Can anyone else take this over?

See #680.