environment.ml

   1 open Types;;
   2 module Environment = struct
   3 (**********************************************************************
   4                              ENVIRONMENT
   5 **********************************************************************)
   6 let push_env_frame env formals actuals =
   7
   8   let h = Hashtbl.create (List.length formals) in
   9     List.iter
  10       (function (name, obj) -> Hashtbl.add h name obj )
  11       (List.combine formals actuals);
  12     h::env
  13 ;;
  14
  15 let find_frame env k =
  16   try
  17     List.find (fun x -> Hashtbl.mem x k) env
  18   with
  19       Not_found -> raise (Scheme_eval_error ("undefined: "^k));;
  20
  21 let lookup env k =
  22   try
  23     Hashtbl.find  (find_frame env k) k
  24   with
  25       Not_found -> raise (Scheme_eval_error ("undefined: "^k));;
  26
  27 let update env k v =
  28   try
  29     Hashtbl.replace (find_frame env k) k v
  30   with
  31       Not_found -> raise (Scheme_eval_error ("undefined: "^k));;
  32
  33 let current_env_frame  = function
  34     (e::rest) -> e
  35   | [] -> assert false
  36 ;;
  37
  38 let initial_env = [Hashtbl.create 1]
  39
  40 end