[Ocaml-lib-devel] Constructing lists

[Richard J. <ri...@an...>]

A common pattern, one which I use frequently anyway, is to write a
pair of functions like this:

  let add_elem, get_elems =
    let elems = ref [] in
    let add_elem r = elems := r :: !elems in
    let get_elems () = List.rev !elems in
    add_elem, get_elems;;

followed by imperative-style code to add elements to the list, and
finally return the list with get_elems ().

Could ExtList contain such a "list building" function?  ie. It would
be a function which returned a pair of functions as above, something
like:

  let add, get = ExtList.List.build ()

where build would be defined as:

  let build () =
    let xs = ref [] in
    let add x = xs := x :: !xs in
    let get () = List.rev !xs in
    add, get

Thoughts?

Rich.

-- 
Richard Jones, CTO Merjis Ltd.
Merjis - web marketing and technology - http://merjis.com
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