compiler and vm: added modulo, rem and abs

lib/vm/native.ml

@@ -34,6 +34,20 @@ let numeric_mul = numeric_generic ( * ) ( *. )
 let numeric_div x y =
   NDouble ((float_of_numeric x) /. (float_of_numeric y))
 
+module type Num = sig
+  type t
+  val add : t -> t -> t
+  val zero : t
+  val rem : t -> t -> t
+end
+
+let aux_mod (type a) (module M : Num with type t = a) (x:a) (y:a) =
+  let z = M.rem x y in
+  if z < M.zero then M.add z y else z
+let numeric_mod = numeric_generic (aux_mod (module Int)) (aux_mod (module Float))
+let numeric_rem = numeric_generic (Int.rem) (Float.rem)
+
+
 let builtin_print (v : Types.value ref list) =
   List.iter (fun r -> print_endline (print_value !r)) v;
   Types.Nil
@@ -57,13 +71,32 @@ let builtin_div vs =
   | f :: rest -> of_numeric (List.fold_left numeric_div (to_numeric !f) (List.map (fun r -> to_numeric !r) rest))
   | [] -> failwith "invalid number of arguments for division: 0"
 
+let make_single_func s f = function
+  | first :: [] -> f first 
+  | v -> failwith ("invalid number of arguments for " ^s ^ ": " ^ (string_of_int (List.length v)))
+
+let make_two_func s f = function
+  | first :: second :: [] -> f first second 
+  | v -> failwith ("invalid number of arguments for " ^ s ^ ": " ^ (string_of_int (List.length v)))
+
+
+let builtin_abs = make_single_func "ABS" (fun f -> of_numeric (match to_numeric !f with
+                                                     | NInt x -> NInt (Int.abs x)
+                                                     | NDouble x -> NDouble (Float.abs x)))
+let builtin_mod =
+  make_two_func "MOD" (fun x y -> of_numeric (numeric_mod (to_numeric !x) (to_numeric !y)))
+let builtin_rem =
+  make_two_func "REM" (fun x y -> of_numeric (numeric_rem (to_numeric !x) (to_numeric !y)))
 
 let table = [|
     builtin_print;
     builtin_add;
     builtin_sub;
     builtin_mul;
-    builtin_div
+    builtin_div;
+    builtin_abs;
+    builtin_mod;
+    builtin_rem
   |]