lazy thoughts

[Andrei Alexandrescu]

Brian Palmer wrote:
> Andrei Alexandrescu Wrote:
> 
>> [snip snip] Yah, I'll look into it. One thing is that not that many
>> functions will end up being lazy. For example, reduce is eager (I
>> think it's uninteresting to have it default to laziness).
> 
> Actually if I can pick a nit real quick here, I disagree that a lazy
> reduce isn't interesting, there's a lot of very interesting
> algorithms based off of lazy folding, and lazy folding of infinite
> lists. After all, the fold is the "mother" of all those other
> iterators like map, filter, etc. In any case, it sounds like
> implementing a lazy reduce should be simple enough even if it's not
> in std.algorithm itself, so I'm not set on it.

Exactly. Lazy reduce is easy to implement e.g. by means of a delegate. 
On the other hand, lazy map is unimplementable from eager map.

Andrei