ocaml/env.ml

   1 module T = Types.Types
   2 module Data = Map.Make (String)
   3
   4 type env = {
   5   outer : env option;
   6   data : Types.mal_type Data.t ref;
   7 }
   8
   9 let make outer = { outer = outer; data = ref Data.empty }
  10
  11 let set env sym value =
  12   match sym with
  13     | T.Symbol { T.value = key } -> env.data := Data.add key value !(env.data)
  14     | _ -> raise (Invalid_argument "set requires a Symbol for its key")
  15
  16 let rec find env sym =
  17   match sym with
  18     | T.Symbol { T.value = key } ->
  19         (if Data.mem key !(env.data) then
  20            Some env
  21          else
  22            match env.outer with
  23              | Some outer -> find outer sym
  24              | None -> None)
  25     | _ -> raise (Invalid_argument "find requires a Symbol for its key")
  26
  27 let get env sym =
  28   match sym with
  29     | T.Symbol { T.value = key } ->
  30       (match find env sym with
  31          | Some found_env -> Data.find key !(found_env.data)
  32          | None -> raise (Invalid_argument ("'" ^ key ^ "' not found")))
  33     | _ -> raise (Invalid_argument "get requires a Symbol for its key")