* Streams and call-by-need
@ 2006-05-26 14:52 Christoph Bauer
2006-05-26 15:17 ` [Caml-list] " Nicolas Pouillard
0 siblings, 1 reply; 2+ messages in thread
From: Christoph Bauer @ 2006-05-26 14:52 UTC (permalink / raw)
To: caml-list
Hi,
do streams support call-by-need? This looks like call-by-name:
# let s = [< '(print_endline "a"); '(print_endline "b") >]
;;
val s : unit Stream.t = <abstr>
# let t = [< s; s >]
;;
val t : unit Stream.t = <abstr>
# Stream.next t;;
a
- : unit = ()
# Stream.next t;;
b
- : unit = ()
# Stream.next t;;
a
- : unit = ()
# Stream.next t;;
b
- : unit = ()
Christoph Bauer
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Caml-list] Streams and call-by-need
2006-05-26 14:52 Streams and call-by-need Christoph Bauer
@ 2006-05-26 15:17 ` Nicolas Pouillard
0 siblings, 0 replies; 2+ messages in thread
From: Nicolas Pouillard @ 2006-05-26 15:17 UTC (permalink / raw)
To: Christoph Bauer; +Cc: caml-list
On 5/26/06, Christoph Bauer <christoph.bauer@lms-gmbh.de> wrote:
> Hi,
>
> do streams support call-by-need? This looks like call-by-name:
>
> # let s = [< '(print_endline "a"); '(print_endline "b") >]
> ;;
> val s : unit Stream.t = <abstr>
> # let t = [< s; s >]
> ;;
> val t : unit Stream.t = <abstr>
> # Stream.next t;;
> a
> - : unit = ()
> # Stream.next t;;
> b
> - : unit = ()
> # Stream.next t;;
> a
> - : unit = ()
> # Stream.next t;;
> b
> - : unit = ()
>
Since your stream elements make function calls they are boxed in
functions taking unit.
Thus calls are delayed, but that's not real lazy values, the function
call is always done.
--
Nicolas Pouillard
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