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|
(* TEST
expect;
*)
(* expect-tests currently do not collect I/O,
so we emulate I/O by collecting output in a "log" *)
let logger () =
let log = ref [] in
let show_log v = List.rev !log, v in
let log v = log := v :: !log in
log, show_log
[%%expect{|
val logger : unit -> ('a -> unit) * ('b -> 'a list * 'b) = <fun>
|}]
let _ =
let log, show_log = logger () in
let x = lazy (log "x"; 41) in
let y =
log "map";
Lazy.map (fun n -> log "y"; n+1) x in
log "force y";
show_log (Lazy.force y)
;;
[%%expect{|
- : string list * int = (["map"; "force y"; "x"; "y"], 42)
|}]
let _ =
let log, show_log = logger () in
let x = lazy (log "x"; 41) in
let y =
log "map_val";
Lazy.map_val (fun n -> log "y"; n+1) x in
assert (not (Lazy.is_val y));
log "force y";
show_log (Lazy.force y)
;;
[%%expect{|
- : string list * int = (["map_val"; "force y"; "x"; "y"], 42)
|}]
let _ =
let log, show_log = logger () in
let x = lazy (log "x"; 41) in
log "force x";
let () = ignore (Lazy.force x) in
let y =
log "map_val";
Lazy.map_val (fun n -> log "y"; n+1) x in
assert (Lazy.is_val y);
log "y is val";
show_log (Lazy.force y)
;;
[%%expect{|
- : string list * int = (["force x"; "x"; "map_val"; "y"; "y is val"], 42)
|}]
|
