langs a-z

Task/Search-a-list/OCaml/search-a-list.ocaml

@@ -0,0 +1,23 @@
+# let find_index pred lst =
+    let rec loop n = function
+       []    -> raise Not_found
+     | x::xs -> if pred x then n
+                          else loop (n+1) xs
+    in
+    loop 0 lst;;
+val find_index : ('a -> bool) -> 'a list -> int = <fun>
+
+# let haystack =
+    ["Zig";"Zag";"Wally";"Ronald";"Bush";"Krusty";"Charlie";"Bush";"Bozo"];;
+val haystack : string list =
+  ["Zig"; "Zag"; "Wally"; "Ronald"; "Bush"; "Krusty"; "Charlie"; "Bush";
+   "Bozo"]
+# List.iter (fun needle ->
+               try
+                 Printf.printf "%i %s\n" (find_index ((=) needle) haystack) needle
+               with Not_found ->
+                 Printf.printf "%s is not in haystack\n" needle)
+            ["Washington"; "Bush"];;
+Washington is not in haystack
+4 Bush
+- : unit = ()