Re: They are not the same

[John Colvin]

On Saturday, 5 April 2014 at 01:28:06 UTC, bearophile wrote:
Can you spot the difference between foo1 and foo2?

import std.algorithm: map;
import std.range: iota;

void foo1(in int[] a, in int[] b) pure {
    int[] r;
    foreach (immutable i; 0 .. a.length)
        r ~= (i % 2) ? a[i] : b[i];
}

void foo2(in int[] a, in int[] b) pure {
    int[] r;
    foreach (x; iota(a.length)
                .map!(i => (i % 2) ? a[i] : b[i]))
        r ~= x;
}

void main() {}



Sometimes variants of this problem hit me. I don't even know if 
this simple problem has a name. Is it impossible to solve?

Bye,
bearophile

Pity...

I think there's an argument that this should work, on the grounds 
that the context pointer is just another argument and therefore 
the lambda can be weakly pure.