> http://mamememo.blogspot.com/2009/11/enumerablerrb-enumerable-lazy-version.html
> http://d.hatena.ne.jp/ku-ma-me/20091111/p2 (in Japanese)

Excellent.  I was wondering where those lazy versions of select were...
As a note, though--I think it does use fibers if you do a #next call on one...

> Matz said that these methods are acceptable to be embedded into the
> core, but did not accept their names (selector, mapper, etc.).
> Instead, Matz suggested enum_select, enum_map, etc., but I dislike
> them because they are too verbose.

perhaps select_enum?

>ruby bench.rb
0.078125 # current select
0.515625 # selector

I think we should keep both, since it's such a slowdown (and having to
call #to_a everywhere might be a drag...) :)

> According to the commit log, it seemed to be "an undocumented feature",
> and was removed intentionally.

Ahh ok.
Thanks.
-r