add pass uniquify_var and interp_var

diff --git a/ocaml_yacc/calc.ml b/ocaml_yacc/calc.ml
index edb18d4e0d0fb7ee89823830f1c155c0d1f65bf7..6d5954ab1d0120ea4fe5e151352f53f0af7d697b 100644 (file)
--- a/ocaml_yacc/calc.ml
+++ b/ocaml_yacc/calc.ml
@@ -7,22 +7,33 @@ let rec ast_to_string ast = match ast with
 | Ast.Node ls -> "[" ^ String.concat " " (List.map ast_to_string ls) ^ "]"
 ;;
 
+(**environment for the interpreter*)
+class environment =
+    object (self)
+      val mutable tbl : (string, int) Hashtbl.t = Hashtbl.create 10
+      method add_val key data = Hashtbl.add tbl key data
+      method get_val key = Hashtbl.find tbl key
+         method get_tbl = tbl
+    end;;
+
+
+
+
 (** interpreter for interp_int*)
-class interp_int x_init =
+class interp_int =
     object (self)
-      val mutable x = x_init
-      method interp code = match code with
+      method interp (env : environment) code = match code with
                | Ast.Int x -> x
                | Ast.Node [Ast.Leaf "+"; lhs; rhs] ->
-                       let x1 = self#interp lhs in
-                       let x2 = self#interp rhs in
+                       let x1 = self#interp env lhs in
+                       let x2 = self#interp env rhs in
                        x1+x2 
                | Ast.Node [Ast.Leaf "-"; lhs; rhs] ->
-                       let x1 = self#interp lhs in
-                       let x2 = self#interp rhs in
+                       let x1 = self#interp env lhs in
+                       let x2 = self#interp env rhs in
                        x1-x2 
                | Ast.Node [Ast.Leaf "-"; x] ->
-                       let x1 = self#interp x in
+                       let x1 = self#interp env x in
                        0-x1 
                | Ast.Node [Ast.Leaf "%apply" ; Ast.Leaf "read"; Ast.Int 0] ->
                        let input = read_int_opt () in
@@ -32,6 +43,45 @@ class interp_int x_init =
                | _ -> raise (Exc "unsupported")
     end;;
 
+(** interpreter for interp_var*)
+class interp_var = 
+       object (self)
+      inherit interp_int as super
+               method interp (env : environment) code = match code with
+                       | Ast.Leaf var -> env#get_val var
+                       | Ast.Node [Ast.Leaf "%let"; Ast.Node[typ; Ast.Leaf var; data]; body] ->
+                               let new_val = self#interp env data in
+                               let _ = env#add_val var new_val in
+                               self#interp env body
+
+                       | _ -> super#interp env code
+end;;
+
+let prime_op = ["+"; "-"];;
+
+(** PASS1 : uniquify the variable*)
+let rec uniquify_var_pass ast (tbl : (string, int) Hashtbl.t) = match ast with
+       | Ast.Int x -> ast
+       | Ast.Leaf var -> Ast.Leaf (var ^ "." ^ (string_of_int(Hashtbl.find tbl var)))
+       | Ast.Node [Ast.Leaf "-" ; x] ->  Ast.Node [Ast.Leaf "-"; uniquify_var_pass x tbl]
+
+
+       | Ast.Node [Ast.Leaf "%let"; Ast.Node[typ; Ast.Leaf var; data]; body] ->
+               let _ = if not(Hashtbl.mem tbl var) then
+                               (Hashtbl.add tbl var 0) else
+                               Hashtbl.replace tbl var ((Hashtbl.find tbl var)+1) in
+               let new_var = Ast.Leaf (var ^ "." ^(string_of_int(Hashtbl.find tbl var))) in
+               let rhs = uniquify_var_pass data tbl in
+               Ast.Node [Ast.Leaf "%let"; Ast.Node[typ; new_var; rhs];
+       uniquify_var_pass body tbl]
+       | Ast.Node [Ast.Leaf op ; lhs; rhs] -> if List.mem op prime_op  then
+                                                                                                       Ast.Node [Ast.Leaf op ;
+                                                                                                       uniquify_var_pass lhs tbl;
+                                                                                                       uniquify_var_pass rhs tbl] else
+                                                                                                       Ast.Node [uniquify_var_pass (Ast.Leaf op) tbl;
+                                                                                                       uniquify_var_pass lhs tbl;
+                                                                                                       uniquify_var_pass rhs tbl]
+       | _ -> ast
 
 
 
@@ -39,10 +89,14 @@ class interp_int x_init =
         let _ =
           try
             let lexbuf = Lexing.from_channel stdin in
-                       let interp = new interp_int 0 in
+                       let env = new environment in
+                       let interp = new interp_var in
             while true do
+                         let hasht = (Hashtbl.create 10) in
               let result = Parser.main Lexer.token lexbuf in
-                Printf.printf "%d" (interp#interp result); print_newline(); flush stdout
+                         let result2 = uniquify_var_pass result hasht in 
+                               Printf.printf "%s\n" (ast_to_string result2);
+                Printf.printf "%d" (interp#interp env result2); print_newline(); flush stdout
             done
           with Lexer.Eof ->
             exit 0