ocaml-lib-devel

[Ocaml-lib-devel] Enum

[Bill W. <wil...@co...>]

What exactly *is* an enum?  Is it a lazy list?  sequence? totally
ordered multiset?

Can an enum be (potentially) infinite?  For example, what does
    let e = Extlib.Enum,make my_next my_count my_clone in
      Extlib.Enum,append e e
return?  NOTE:
    let x = my_list in x @ x
returns a circular list.  I'm curious as to whether a similar concept
exists with enums.

Thanks,

 -- Bill Wood
    bil...@ac...

Re: [Ocaml-lib-devel] Enum

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

> What exactly *is* an enum?  Is it a lazy list?  sequence? totally
> ordered multiset?

It's more like a lazy sequence. Since it's lazy, it can be infinite if you
define a "next" function always returning an element. But it's consuming so
when enumerating "append e e" you first consume "e" and then "e" is empty,
so it's not circular.

Nicolas

Re: [Ocaml-lib-devel] Enum

[Bill W. <wil...@co...>]

   . . .
> It's more like a lazy sequence. Since it's lazy, it can be infinite if you
> define a "next" function always returning an element. But it's consuming so
> when enumerating "append e e" you first consume "e" and then "e" is empty,
> so it's not circular.

It seems very similar to Scheme streams implemented by means of "delay"
and "force", yes?

Thanks,

 -- Bill Wood