History variables: Difference between revisions

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@@ Line 986: / Line 986: @@
 =={{header|OCaml}}==
+The easiest solution is to use the Stack module coming with OCaml's standard library:
 <lang ocaml>
+open Stack
-module History =
+(* This is only for convenience when typing code *)
-struct
+module H = Stack
+let show_entry e =
-  type hist = { mutable hve: int list }
+    Printf.printf "History entry: %5d\n" e
-  let init () = { hve = [] }
-  let push h e =
-    h.hve <- e::h.hve
-  let pop h =
-    match h.hve with
-    | [] -> ()
-    | v::t -> h.hve <- t; print_int v; print_newline ()
-  let show hv =
-    List.iter (fun v -> Printf.printf "History entry: %5d\n" v) hv.hve
-end
-open History
-module H = History
 let () =
-  let hv = H.init() in
+  let  hs = H.create() in
-  H.push hv 111;
+  H.push 111 hs ;
-  H.push hv 4;
+  H.push 4 hs ;
-  H.push hv 42;
+  H.push 42 hs ;
-  H.show hv;
+  H.iter show_entry hs;
-  H.pop hv;
+  hs |> H.pop |> Printf.printf "%d\n";
-  H.pop hv;
+  hs |> H.pop |> Printf.printf "%d\n";
-  H.pop hv
+  hs |> H.pop |> Printf.printf "%d\n"
 </lang>