lama_byterun/src/SM.ml

open GT       
open Language
       
(* The type for the stack machine instructions *)
@type insn =
(* binary operator                 *) | BINOP of string
(* put a constant on the stack     *) | CONST of int                 
(* read to stack                   *) | READ
(* write from stack                *) | WRITE
(* load a variable to the stack    *) | LD    of string
(* store a variable from the stack *) | ST    of string
(* a label                         *) | LABEL of string
(* unconditional jump              *) | JMP   of string                                                                                                                
(* conditional jump                *) | CJMP  of string * string
(* begins procedure definition     *) | BEGIN of string list * string list
(* end procedure definition        *) | END
(* calls a procedure               *) | CALL  of string with show
                                                   
(* The type for the stack machine program *)                                                               
type prg = insn list

(* The type for the stack machine configuration: control stack, stack and configuration from statement
   interpreter
 *)
type config = (prg * State.t) list * int list * Stmt.config

(* Stack machine interpreter

     val eval : env -> config -> prg -> config

   Takes an environment, a configuration and a program, and returns a configuration as a result. The
   environment is used to locate a label to jump to (via method env#labeled <label_name>)
*)                         
let eval env ((cstack, stack, ((st, i, o) as c)) as conf) = failwith "Not implemented"

(* Top-level evaluation

     val run : prg -> int list -> int list

   Takes a program, an input stream, and returns an output stream this program calculates
*)
let run p i =
  let module M = Map.Make (String) in
  let rec make_map m = function
  | []              -> m
  | (LABEL l) :: tl -> make_map (M.add l tl m) tl
  | _ :: tl         -> make_map m tl
  in
  let m = make_map M.empty p in
  let (_, _, (_, _, o)) = eval (object method labeled l = M.find l m end) ([], [], (State.empty, i, [])) p in o

(* Stack machine compiler

     val compile : Language.t -> prg

   Takes a program in the source language and returns an equivalent program for the
   stack machine
*)
let compile (defs, p) = failwith "Not implemented"