Re: [Caml-list] Lazy recomputing

[skaller <skaller@users.sourceforge.net>]

On Wed, 2004-06-02 at 01:22, Hans Ole Rafaelsen wrote:
> let _ =
>   List.iter
>     (fun (k,v) -> Hashtbl.add tbl k v)
>     [
>       ("a", fun () ->  1);
>       ("c", fun () -> ((Hashtbl.find tbl "b") ()) + ((Hashtbl.find tbl "a") 
> ()));
>       ("b", fun () -> 4);
>     ]

Of course, this will recompute the same result needlessly
to make sure it also computes the new result when needed.
Also the functions are bound to a particular hashtble,
which isn't so nice: might be nicer to write:

 fun tbl -> find tbl "b" + find tbl "a"

and 

let eval tbl key = find tbl key tbl;;
let tbl = create 97;;
let eval_tbl key = eval tbl key;;




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John Skaller, mailto:skaller@users.sf.net
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