[Ocaml-lib-devel] Re: [PATCH] updated enum: now concat uses t.fast

[Alan P. <ap...@re...>]

In article <01b201c32e41$ce0853b0$2413f9ca@WARP>, Nicolas Cannasse wrote:
>
> I'll try to review theses patch when I have some time.
> I think it's good idea to remove the try..catch blocks when we have a "fast"
> count in concat and append, because they occur in each call to next . But
> for fold / iter , I'm not sure, mainly because a fast count can still be
> O(N) and cost more than having one try...catch block setuped. Could you do
> some benchs using ExtList.enum instead of Enum.init ? The "fast" count is
> O(N) here in this case ( but is computed only once ). With big lists ( "when
> we need speed" ) I'm pretty sure it will be better not to call count.

I was operating under the assumption that "fast" would be set only for
data structures that had their count readily available -- for
instance, dynarray and init.