Re: [Ocaml-lib-devel] Enum module

[Brian H. <bri...@ql...>]

On Wed, 16 Apr 2003, Nicolas Cannasse wrote:

> If you look at enum.mli, there is NO WAY of doing a next() !
> Why ? because most of the time ( 99.99999% ) , you want to apply the same
> algorithm to all the elements of your data structure, and I have the Java
> while( e.hasMoreElements() ) { Object o = e.nextElement(); ... }. The "next"
> function has to be implemented by the data structure, so the user won't know
> about it, and the data structure of_enum implementation itself will have to
> use most of the time Enum.fold/iter to fill itself.

I was going to reply with a 'here is how you do it' code example- but
having played with it you're right.  The problem is dealing with an empty
enumeration.  You end up with a Some of/None problem.  There is no nice
way to implement the API I was advocating.  You were right, and I withdraw
the request.

Brian