diff --git a/src/Language.ml b/src/Language.ml
index 200349831..7d0348d32 100644
--- a/src/Language.ml
+++ b/src/Language.ml
@@ -53,8 +53,10 @@ module Loc =
   end
 
 let report_error ?(loc=None) str =
-  raise (Semantic_error (str ^ match loc with None -> "" | Some (l, c) -> Printf.sprintf " at (%d, %d)" l c))
+  raise (Semantic_error (str ^ match loc with None -> "" | Some (l, c) -> Printf.sprintf " at (%d, %d)" l c));;
   
+@type k = Unmut | Mut | FVal with show, html
+
 (* Values *)
 module Value =
   struct
@@ -148,7 +150,7 @@ module Builtin =
 
     let list        = ["read"; "write"; ".elem"; ".length"; ".array"; ".stringval"]
     let bindings () = List.map (fun name -> name, Value.Builtin name) list
-    let names       = List.map (fun name -> name, false) list
+    let names       = List.map (fun name -> name, FVal) list
                  
     let eval (st, i, o, vs) args = function
     | "read"     -> (match i with z::i' -> (st, i', o, (Value.of_int z)::vs) | _ -> failwith "Unexpected end of input")
@@ -170,12 +172,12 @@ module Builtin =
 (* States *)
 module State =
   struct
-
+                                 
     (* State: global state, local state, scope variables *)
     @type 'a t =
     | I
-    | G of (string * bool) list * (string, 'a) arrow
-    | L of (string * bool) list * (string, 'a) arrow * 'a t
+    | G of (string * k) list * (string, 'a) arrow
+    | L of (string * k) list * (string, 'a) arrow * 'a t
     with show, html
 
     (* Get the depth level of a state *)
@@ -213,7 +215,7 @@ module State =
     let in_scope x s = List.exists (fun (y, _) -> y = x) s
 
     (* Scope operation: checks if a name designates variable *)
-    let is_var x s = try List.assoc x s with Not_found -> false
+    let is_var x s = try Mut = List.assoc x s with Not_found -> false
                     
     (* Update: non-destructively "modifies" the state s by binding the variable x
        to value v and returns the new state w.r.t. a scope
@@ -455,8 +457,8 @@ module Expr =
          let vars, body, bnds =
            List.fold_left
              (fun (vs, bd, bnd) -> function
-              | (name, (_, `Variable value)) -> (name, true) :: vs, (match value with None -> bd | Some v -> Seq (Ignore (Assign (Ref name, v)), bd)), bnd
-              | (name, (_, `Fun (args, b)))  -> (name, false) :: vs, bd, (name, Value.FunRef (name, args, b, 1 + State.level st)) :: bnd
+              | (name, (_, `Variable value)) -> (name, Mut) :: vs, (match value with None -> bd | Some v -> Seq (Ignore (Assign (Ref name, v)), bd)), bnd
+              | (name, (_, `Fun (args, b)))  -> (name, FVal) :: vs, bd, (name, Value.FunRef (name, args, b, 1 + State.level st)) :: bnd
              )
              ([], body, [])
              (List.rev @@
@@ -512,7 +514,7 @@ module Expr =
              | Value.Builtin name ->
                 Builtin.eval (st, i, o, vs') es name
              | Value.Closure (args, body, closure) ->
-                let st' = State.push (State.leave st closure.(0)) (State.from_list @@ List.combine args es) (List.map (fun x -> x, true) args) in
+                let st' = State.push (State.leave st closure.(0)) (State.from_list @@ List.combine args es) (List.map (fun x -> x, Mut) args) in
                 let st'', i', o', vs'' = eval (st', i, o, []) Skip body in
                 closure.(0) <- st'';
                 (State.leave st'' st, i', o', match vs'' with [v] -> v::vs' | _ -> Value.Empty :: vs')                      
@@ -566,7 +568,7 @@ module Expr =
              in
              match match_patt patt v (Some State.undefined) with
              | None     -> branch conf tl
-             | Some st' -> eval (State.push st st' (List.map (fun x -> x, false) @@ Pattern.vars patt), i, o, vs) k (Seq (body, Leave))
+             | Some st' -> eval (State.push st st' (List.map (fun x -> x, Unmut) @@ Pattern.vars patt), i, o, vs) k (Seq (body, Leave))
          in
          eval conf Skip (schedule_list [e; Intrinsic (fun conf -> branch conf bs)])
 
diff --git a/src/SM.ml b/src/SM.ml
index 7edf00423..cad3316bf 100644
--- a/src/SM.ml
+++ b/src/SM.ml
@@ -476,7 +476,7 @@ object (self : 'self)
                    let _, intfs = Interface.find import paths in
                    List.fold_left
                      (fun env -> function
-                      | `Variable name -> env#add_name     name `Extern true
+                      | `Variable name -> env#add_name     name `Extern Mut
                       | `Fun name      -> env#add_fun_name name `Extern 
                       | _              -> env
                      )
@@ -513,6 +513,7 @@ object (self : 'self)
     List.filter (function (_, `Local, _) -> false | _ -> true) decls
     
   method push_scope (blab : string) (elab : string) =
+    (*Printf.printf "push: Scope local index = %d\n" scope.local_index;*)
     match scope.st with
     | State.I ->
        {<
@@ -541,7 +542,7 @@ object (self : 'self)
          scope = {
            scope with
            st          = x;
-           local_index = scope.local_index - List.length xs;
+           local_index = ((*Printf.printf "pop: Scope local index = %d\n" (scope.local_index - List.length xs);*) scope.local_index - List.length (List.filter (fun (_, x) -> x <> FVal) xs) (*xs*));
            scopes      = match scope.scopes with
                            [_]            -> scope.scopes
                          | hs :: ps :: tl -> {ps with subs = hs :: ps.subs} :: tl
@@ -581,7 +582,7 @@ object (self : 'self)
                      | State.I | State.G _ ->
                         invalid_arg "wrong scope in add_arg"
                      | State.L (names, s, p) ->
-                        State.L (check_name_and_add names name true, State.bind name (Value.Arg scope.arg_index) s, p)
+                        State.L (check_name_and_add names name Mut, State.bind name (Value.Arg scope.arg_index) s, p)
                     );
         arg_index = scope.arg_index + 1
       }
@@ -593,7 +594,7 @@ object (self : 'self)
     |  _  ->
        report_error (Printf.sprintf "external/public definitions (\"%s\") not allowed in local scopes" (Subst.subst name))
     
-  method add_name (name : string) (m : [`Local | `Extern | `Public | `PublicExtern]) (mut : bool) = {<
+  method add_name (name : string) (m : [`Local | `Extern | `Public | `PublicExtern]) (mut : Language.k) = {<
       decls = (name, m, false) :: decls;
       scope = {
         scope with
@@ -604,7 +605,7 @@ object (self : 'self)
                           State.G ((match m with `Extern | `PublicExtern -> names | _ -> check_name_and_add names name mut), State.bind name (Value.Global name) s)
                        | State.L (names, s, p) ->
                           self#check_scope m name;
-                          State.L (check_name_and_add names name mut, State.bind name (Value.Local scope.local_index) s, p)
+                          State.L (check_name_and_add names name mut, State.bind name (Value.Local ((*Printf.printf "Var: %s -> %d\n" name scope.local_index;*) scope.local_index)) s, p) (* !! *)
                       );
         local_index = (match scope.st with State.L _ -> scope.local_index + 1 | _ -> scope.local_index);
         nlocals     = (match scope.st with State.L _ -> max (scope.local_index + 1) scope.nlocals | _ -> scope.nlocals);
@@ -624,10 +625,10 @@ object (self : 'self)
       | State.I ->
          invalid_arg "uninitialized scope"
       | State.G (names, s) ->
-         State.G ((match m with `Extern | `PublicExtern -> names | _ -> check_name_and_add names name false), State.bind name (Value.Fun name') s)
+         State.G ((match m with `Extern | `PublicExtern -> names | _ -> check_name_and_add names name FVal), State.bind name (Value.Fun name') s)
       | State.L (names, s, p) ->
          self#check_scope m name;
-         State.L (check_name_and_add names name false, State.bind name (Value.Fun name') s, p)        
+         State.L (check_name_and_add names name FVal, State.bind name (Value.Fun name') s, p)        
     in
     {<
       decls = (name, m, true) :: decls;
@@ -739,8 +740,10 @@ let compile cmd ((imports, infixes), p) =
     let env, code =
       List.fold_left
         (fun (env, acc) (name, path) ->
-           let env = env#add_name name `Local true in
+          (*Printf.printf "Bindings..\n";*)
+           let env = env#add_name name `Local Mut in
            let env, dsg = env#lookup name in
+          (*Printf.printf "End Bindings..\n";*)
            env,
            ([DUP] @
             List.concat (List.map (fun i -> [CONST i; CALL (".elem", 2, false)]) path) @
@@ -774,8 +777,8 @@ let compile cmd ((imports, infixes), p) =
          (fun (env, e, funs) ->
            function
            | name, (m, `Fun (args, b))     -> env#add_fun_name name m, e, (name, args, m, b) :: funs
-           | name, (m, `Variable None)     -> env#add_name name m true, e, funs
-           | name, (m, `Variable (Some v)) -> env#add_name name m true, Expr.Seq (Expr.Ignore (Expr.Assign (Expr.Ref name, v)), e), funs
+           | name, (m, `Variable None)     -> env#add_name name m Mut, e, funs
+           | name, (m, `Variable (Some v)) -> env#add_name name m Mut, Expr.Seq (Expr.Ignore (Expr.Assign (Expr.Ref name, v)), e), funs
          )
          (env, e, [])
          (List.rev ds)
@@ -792,6 +795,7 @@ let compile cmd ((imports, infixes), p) =
   | Expr.ElemRef (x, i)     -> compile_list tail l env [x; i]
   | Expr.Var      x         -> let env, line = env#gen_line x in
                                let env, acc  = env#lookup x in
+                               (*Printf.printf "Looking up %s -> %s\n" x (show(Value.designation) acc);*)
                                (match acc with Value.Fun name -> env#register_call name, false, line @ [PROTO (name, env#current_function)] | _ -> env, false, line @ [LD acc])
   | Expr.Ref      x         -> let env, line = env#gen_line x in
                                let env, acc  = env#lookup x in env, false, line @ [LDA acc]
diff --git a/src/version.ml b/src/version.ml
index 08b173c4a..be85ec54e 100644
--- a/src/version.ml
+++ b/src/version.ml
@@ -1 +1 @@
-let version = "Version 1.00, 8f01e5eb5, Tue Nov 24 01:51:11 2020 +0300"
+let version = "Version 1.00, 66dc5c306, Tue Nov 24 23:11:17 2020 +0300"