From: gotoken@... (GOTO Kentaro)
Date: 2000-01-28T12:53:57+09:00
Subject: [ruby-talk:01191] Re: Enumerable and index

In message "[ruby-talk:01190] Re: Enumerable and index"
    on 00/01/27, Dave Thomas <Dave@thomases.com> writes:
>I guess this is the difference between Iterable and
>Enumerable. Iterable simply implies a .each method, while Enumerable
>means that .each stops and is repeatable. So, IO would be Iterable,
>and Array would be Enumerable. I guess that Enumerable < Iterable.
>
>(And no, Iterable is most definitely _not_ a word ;-)

:-)

From the other point of veiw, most methods of Enumerable requires of
finiteness while each can work for possibly infinite stream.  In the
term of computer science, enumerable is referred as existence of a map
from integer to object. In this sense, I guess IO is proper
Enumerable.  On the other hand, classes else IO is Finite. I guess
Finite < Enumerable.  But Finite is not "-able" and most class is
finite whereas they don't have .each.

-- gotoken