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

[Nicolas C. <war...@fr...>]

> Here's an updated version of my patch to enum.ml, including using fast
> in Enum.concat.  A try block on every call to next() was quite
> expensive.  I wasn't able to think of anything useful to do with
> t.count (as opposed to tn.count) in concat, though.
>
> If it's more convenient, I've also posted my modified enum.ml at:
>
>   http://recalcitrant.org/~apost/enum.ml

Thanks Alan.
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.

Nicolas Cannasse