associative arrays: iteration is finally here

[bearophile]

bearophile:

> Pelle Månsson:
> > I agree with this. I usually want exceptions.
> 
> A problem with this is that currently exceptions are very slow in D compiled with DMD (something like up to 11 times slower than Java exceptions, about 2-4 times slower than Python exceptions. I have a benchmark for this on my site).

I have just redone the timings with LDC on Ubuntu (I'll put the timings online soon): Java is only about 2.2 times faster. This is much better and almost acceptable.

Bye,
bearophile