Re: [Ocaml-lib-devel] Re: Abstract IO

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

> Note that I suggested seek only for input streams.
>
> If I understand the interface correctly an object of type ('a, 'b) input
> semantically corresponds to a list of objects of type 'a with one
> selected position (the current one). Therefore, the semantics of seek
> and pos should be:
>
>  If "in" corresponds to the list a_0,...,a_n and a_i is the currently
>  selected element, then "pos in" should return i and "seek in k" should
>  mark a_k as new selected element.

The only problem I see is that doesn't scale well with strings.
As I show you before, you might consider strings as N-char-lists, but the
semantics of reading depends for example if the file is open in binary of
text mode.
Other case : if you have a file containing N strings of X characters
separated by \0 , then reading 3 strings will give you a position of
3*(X+1) - including the \0 separator. It's difficult to add a concept of
"length" and "pos" on such tokens , although it's very easy to do in the
case ('a,'a list) input.

Regards,
Nicolas Cannasse