diff --git a/src/lib/exec.rs b/src/lib/exec.rs
index 5ac3e71b7a..65af058838 100644
--- a/src/lib/exec.rs
+++ b/src/lib/exec.rs
@@ -1,9 +1,13 @@
-use gc::Gc;
-use js::value::{to_value, ResultValue, Value, ValueData};
+use gc::{Gc, GcCell};
+use js::function::{Function, RegularFunction};
+use js::object::{INSTANCE_PROTOTYPE, PROTOTYPE};
+use js::value::{from_value, to_value, ResultValue, Value, ValueData};
 use js::{array, console, function, json, math, object, string};
 use std::borrow::Borrow;
+use std::collections::HashMap;
 use syntax::ast::constant::Const;
 use syntax::ast::expr::{Expr, ExprDef};
+use syntax::ast::op::BinOp;
 /// A variable scope
 pub struct Scope {
     /// The value of `this` in the scope
@@ -36,9 +40,9 @@ pub struct Interpreter {
     pub scopes: Vec<Scope>,
 }
 
-impl Executor<Expr> for Interpreter {
+impl Executor for Interpreter {
     fn new() -> Interpreter {
-        let global = Value::new_obj(None);
+        let global = ValueData::new_obj(None);
         object::init(global);
         console::init(global);
         math::init(global);
@@ -66,7 +70,7 @@ impl Executor<Expr> for Interpreter {
     fn make_scope(&mut self, this: Value) -> Scope {
         let scope = Scope {
             this: this,
-            vars: Value::new_obj(None),
+            vars: ValueData::new_obj(None),
         };
         self.scopes.push(scope);
         scope
@@ -76,14 +80,10 @@ impl Executor<Expr> for Interpreter {
         self.scopes.pop().unwrap()
     }
 
-    fn compile<'a>(&self, expr: &'a Expr) -> &'a Expr {
-        expr
-    }
-
     fn run(&mut self, expr: &Expr) -> ResultValue {
         match expr.def {
             ExprDef::ConstExpr(Const::Null) => Ok(to_value(None)),
-            ExprDef::ConstExpr(Const::Undefined) => Ok(Value::undefined()),
+            ExprDef::ConstExpr(Const::Undefined) => Ok(Gc::new(ValueData::Undefined)),
             ExprDef::ConstExpr(Const::Num(num)) => Ok(to_value(num)),
             ExprDef::ConstExpr(Const::Int(num)) => Ok(to_value(num)),
             ExprDef::ConstExpr(Const::String(str)) => Ok(to_value(str)),
@@ -100,11 +100,11 @@ impl Executor<Expr> for Interpreter {
                 Ok(obj)
             }
             ExprDef::LocalExpr(ref name) => {
-                let mut val = Value::undefined();
+                let mut val = Gc::new(ValueData::Undefined);
                 for scope in self.scopes.iter().rev() {
                     let vars = scope.vars;
                     let vars_ptr = vars.borrow();
-                    match *vars_ptr.ptr {
+                    match *vars_ptr.clone() {
                         ValueData::Object(ref obj) => match obj.borrow().get(name) {
                             Some(v) => {
                                 val = v.value;
@@ -143,18 +143,18 @@ impl Executor<Expr> for Interpreter {
                 for arg in args.iter() {
                     v_args.push(try!(self.run(arg)));
                 }
-                match *func.borrow().ptr {
+                match *func {
                     ValueData::Function(ref func) => match *func.borrow() {
-                        NativeFunc(ref ntv) => {
+                        Function::NativeFunc(ref ntv) => {
                             let func = ntv.data;
-                            func(this, try!(self.run(*callee)), v_args)
+                            func(this, try!(self.run(callee)), v_args)
                         }
-                        RegularFunc(ref data) => {
+                        Function::RegularFunc(ref data) => {
                             let scope = self.make_scope(this);
                             let scope_vars_ptr = scope.vars.borrow();
-                            for i in range(0, data.args.len()) {
-                                let name = data.args.get(i);
-                                let expr = v_args.get(i);
+                            for i in 0..data.args.len() {
+                                let name = data.args.get(i).unwrap();
+                                let expr = v_args.get(i).unwrap();
                                 scope_vars_ptr.set_field(name.clone(), *expr);
                             }
                             let result = self.run(&data.expr);
@@ -162,30 +162,32 @@ impl Executor<Expr> for Interpreter {
                             result
                         }
                     },
-                    _ => Err(Gc::new(VUndefined)),
+                    _ => Err(Gc::new(ValueData::Undefined)),
                 }
             }
-            WhileLoopExpr(ref cond, ref expr) => {
-                let mut result = Gc::new(VUndefined);
-                while try!(self.run(*cond)).borrow().is_true() {
-                    result = try!(self.run(*expr));
+            ExprDef::WhileLoopExpr(ref cond, ref expr) => {
+                let mut result = Gc::new(ValueData::Undefined);
+                while try!(self.run(cond)).borrow().is_true() {
+                    result = try!(self.run(expr));
                 }
                 Ok(result)
             }
-            IfExpr(ref cond, ref expr, None) => Ok(if try!(self.run(*cond)).borrow().is_true() {
-                try!(self.run(*expr))
-            } else {
-                Gc::new(VUndefined)
-            }),
-            IfExpr(ref cond, ref expr, Some(ref else_e)) => {
-                Ok(if try!(self.run(*cond)).borrow().is_true() {
-                    try!(self.run(*expr))
+            ExprDef::IfExpr(ref cond, ref expr, None) => {
+                Ok(if try!(self.run(cond)).borrow().is_true() {
+                    try!(self.run(expr))
                 } else {
-                    try!(self.run(*else_e))
+                    Gc::new(ValueData::Undefined)
                 })
             }
-            SwitchExpr(ref val_e, ref vals, ref default) => {
-                let val = try!(self.run(*val_e)).borrow().clone();
+            ExprDef::IfExpr(ref cond, ref expr, Some(ref else_e)) => {
+                Ok(if try!(self.run(cond)).borrow().is_true() {
+                    try!(self.run(expr))
+                } else {
+                    try!(self.run(else_e))
+                })
+            }
+            ExprDef::SwitchExpr(ref val_e, ref vals, ref default) => {
+                let val = try!(self.run(val_e)).borrow().clone();
                 let mut result = Gc::new(ValueData::Null);
                 let mut matched = false;
                 for tup in vals.iter() {
@@ -205,61 +207,63 @@ impl Executor<Expr> for Interpreter {
                     }
                 }
                 if !matched && default.is_some() {
-                    result = try!(self.run(*default.as_ref().unwrap()));
+                    result = try!(self.run(default.as_ref().unwrap()));
                 }
                 Ok(result)
             }
-            ObjectDeclExpr(ref map) => {
+            ExprDef::ObjectDeclExpr(ref map) => {
                 let obj = ValueData::new_obj(Some(self.global));
                 for (key, val) in map.iter() {
                     obj.borrow().set_field(key.clone(), try!(self.run(val)));
                 }
                 Ok(obj)
             }
-            ArrayDeclExpr(ref arr) => {
+            ExprDef::ArrayDeclExpr(ref arr) => {
                 let arr_map = ValueData::new_obj(Some(self.global));
                 let mut index: i32 = 0;
                 for val in arr.iter() {
                     let val = try!(self.run(val));
-                    arr_map.borrow().set_field(index.to_str(), val);
+                    arr_map.borrow().set_field(index.to_string(), val);
                     index += 1;
                 }
                 arr_map.borrow().set_field_slice(
                     INSTANCE_PROTOTYPE,
-                    self.get_global("Array".into_strbuf())
+                    self.get_global("Array".to_string())
                         .borrow()
                         .get_field_slice(PROTOTYPE),
                 );
                 arr_map.borrow().set_field_slice("length", to_value(index));
                 Ok(arr_map)
             }
-            FunctionDeclExpr(ref name, ref args, ref expr) => {
-                let function = RegularFunc(RegularFunction::new(*expr.clone(), args.clone()));
-                let val = Gc::new(VFunction(RefCell::new(function)));
+            ExprDef::FunctionDeclExpr(ref name, ref args, ref expr) => {
+                let function =
+                    Function::RegularFunc(RegularFunction::new(*expr.clone(), args.clone()));
+                let val = Gc::new(ValueData::Function(GcCell::new(function)));
                 if name.is_some() {
                     self.global.borrow().set_field(name.clone().unwrap(), val);
                 }
                 Ok(val)
             }
-            ArrowFunctionDeclExpr(ref args, ref expr) => {
-                let function = RegularFunc(RegularFunction::new(*expr.clone(), args.clone()));
-                Ok(Gc::new(VFunction(RefCell::new(function))))
+            ExprDef::ArrowFunctionDeclExpr(ref args, ref expr) => {
+                let function =
+                    Function::RegularFunc(RegularFunction::new(*expr.clone(), args.clone()));
+                Ok(Gc::new(ValueData::Function(GcCell::new(function))))
             }
-            BinOpExpr(BinNum(ref op), ref a, ref b) => {
-                let v_r_a = try!(self.run(*a));
-                let v_r_b = try!(self.run(*b));
-                let v_a = v_r_a.borrow();
-                let v_b = v_r_b.borrow();
+            ExprDef::BinOpExpr(BinOp::Num(ref op), ref a, ref b) => {
+                let v_r_a = try!(self.run(a));
+                let v_r_b = try!(self.run(b));
+                let v_a = *v_r_a;
+                let v_b = *v_r_b;
                 Ok(Gc::new(match *op {
-                    OpAdd => *v_a + *v_b,
-                    OpSub => *v_a - *v_b,
-                    OpMul => *v_a * *v_b,
-                    OpDiv => *v_a / *v_b,
-                    OpMod => *v_a % *v_b,
+                    OpAdd => v_a + *v_b,
+                    OpSub => v_a - *v_b,
+                    OpMul => v_a * *v_b,
+                    OpDiv => v_a / *v_b,
+                    OpMod => v_a % *v_b,
                 }))
             }
-            UnaryOpExpr(ref op, ref a) => {
-                let v_r_a = try!(self.run(*a));
+            ExprDef::UnaryOpExpr(ref op, ref a) => {
+                let v_r_a = try!(self.run(a));
                 let v_a = v_r_a.borrow();
                 Ok(match *op {
                     UnaryMinus => to_value(-v_a.to_num()),
@@ -268,32 +272,32 @@ impl Executor<Expr> for Interpreter {
                     _ => unreachable!(),
                 })
             }
-            BinOpExpr(BinBit(ref op), ref a, ref b) => {
-                let v_r_a = try!(self.run(*a));
-                let v_r_b = try!(self.run(*b));
-                let v_a = v_r_a.borrow();
-                let v_b = v_r_b.borrow();
+            ExprDef::BinOpExpr(BinOp::Bit(ref op), ref a, ref b) => {
+                let v_r_a = try!(self.run(a));
+                let v_r_b = try!(self.run(b));
+                let v_a = *v_r_a;
+                let v_b = *v_r_b;
                 Ok(Gc::new(match *op {
-                    BitAnd => *v_a & *v_b,
-                    BitOr => *v_a | *v_b,
-                    BitXor => *v_a ^ *v_b,
-                    BitShl => *v_a << *v_b,
-                    BitShr => *v_a >> *v_b,
+                    BitAnd => v_a & v_b,
+                    BitOr => v_a | v_b,
+                    BitXor => v_a ^ v_b,
+                    BitShl => v_a << v_b,
+                    BitShr => v_a >> v_b,
                 }))
             }
-            BinOpExpr(BinComp(ref op), ref a, ref b) => {
-                let v_r_a = try!(self.run(*a));
-                let v_r_b = try!(self.run(*b));
+            ExprDef::BinOpExpr(BinOp::Comp(ref op), ref a, ref b) => {
+                let v_r_a = try!(self.run(a));
+                let v_r_b = try!(self.run(b));
                 let v_a = v_r_a.borrow();
                 let v_b = v_r_b.borrow();
                 Ok(to_value(match *op {
-                    CompEqual if v_a.is_object() => v_r_a.ptr_eq(&v_r_b),
+                    CompEqual if v_a.is_object() => v_r_a == v_r_b,
                     CompEqual => v_a == v_b,
-                    CompNotEqual if v_a.is_object() => !v_r_a.ptr_eq(&v_r_b),
+                    CompNotEqual if v_a.is_object() => v_r_a != v_r_b,
                     CompNotEqual => v_a != v_b,
-                    CompStrictEqual if v_a.is_object() => v_r_a.ptr_eq(&v_r_b),
+                    CompStrictEqual if v_a.is_object() => v_r_a == v_r_b,
                     CompStrictEqual => v_a == v_b,
-                    CompStrictNotEqual if v_a.is_object() => !v_r_a.ptr_eq(&v_r_b),
+                    CompStrictNotEqual if v_a.is_object() => v_r_a != v_r_b,
                     CompStrictNotEqual => v_a != v_b,
                     CompGreaterThan => v_a.to_num() > v_b.to_num(),
                     CompGreaterThanOrEqual => v_a.to_num() >= v_b.to_num(),
@@ -301,30 +305,30 @@ impl Executor<Expr> for Interpreter {
                     CompLessThanOrEqual => v_a.to_num() <= v_b.to_num(),
                 }))
             }
-            BinOpExpr(BinLog(ref op), ref a, ref b) => {
-                let v_a = from_value::<bool>(try!(self.run(*a))).unwrap();
-                let v_b = from_value::<bool>(try!(self.run(*b))).unwrap();
+            ExprDef::BinOpExpr(BinOp::Log(ref op), ref a, ref b) => {
+                let v_a = from_value::<bool>(try!(self.run(a))).unwrap();
+                let v_b = from_value::<bool>(try!(self.run(b))).unwrap();
                 Ok(match *op {
                     LogAnd => to_value(v_a && v_b),
                     LogOr => to_value(v_a || v_b),
                 })
             }
-            ConstructExpr(ref callee, ref args) => {
-                let func = try!(self.run(*callee));
+            ExprDef::ConstructExpr(ref callee, ref args) => {
+                let func = try!(self.run(callee));
                 let mut v_args = Vec::with_capacity(args.len());
                 for arg in args.iter() {
                     v_args.push(try!(self.run(arg)));
                 }
-                let this = Gc::new(VObject(RefCell::new(TreeMap::new())));
+                let this = Gc::new(ValueData::Object(GcCell::new(HashMap::new())));
                 this.borrow()
                     .set_field_slice(INSTANCE_PROTOTYPE, func.borrow().get_field_slice(PROTOTYPE));
-                match *func.borrow() {
-                    VFunction(ref func) => match *func.borrow() {
-                        NativeFunc(ref ntv) => {
+                match *func {
+                    ValueData::Function(ref func) => match *func {
+                        Function::NativeFunc(ref ntv) => {
                             let func = ntv.data;
-                            func(this, try!(self.run(*callee)), v_args)
+                            func(this, try!(self.run(callee)), v_args)
                         }
-                        RegularFunc(ref data) => {
+                        Function::RegularFunc(ref data) => {
                             let scope = self.make_scope(this);
                             let scope_vars_ptr = scope.vars.borrow();
                             for i in range(0, data.args.len()) {
@@ -337,16 +341,16 @@ impl Executor<Expr> for Interpreter {
                             result
                         }
                     },
-                    _ => Ok(Gc::new(VUndefined)),
+                    _ => Ok(Gc::new(ValueData::Undefined)),
                 }
             }
-            ReturnExpr(ref ret) => match *ret {
-                Some(ref v) => self.run(*v),
-                None => Ok(Gc::new(VUndefined)),
+            ExprDef::ReturnExpr(ref ret) => match *ret {
+                Some(ref v) => self.run(v),
+                None => Ok(Gc::new(ValueData::Undefined)),
             },
-            ThrowExpr(ref ex) => Err(try!(self.run(*ex))),
-            AssignExpr(ref ref_e, ref val_e) => {
-                let val = try!(self.run(*val_e));
+            ExprDef::ThrowExpr(ref ex) => Err(try!(self.run(*ex))),
+            ExprDef::AssignExpr(ref ref_e, ref val_e) => {
+                let val = try!(self.run(val_e));
                 match ref_e.def {
                     LocalExpr(ref name) => {
                         self.scope().vars.borrow().set_field(name.clone(), val);
@@ -359,7 +363,7 @@ impl Executor<Expr> for Interpreter {
                 }
                 Ok(val)
             }
-            VarDeclExpr(ref vars) => {
+            ExprDef::VarDeclExpr(ref vars) => {
                 let scope_vars = self.scope().vars;
                 let scope_vars_ptr = scope_vars.borrow();
                 for var in vars.iter() {
@@ -370,17 +374,17 @@ impl Executor<Expr> for Interpreter {
                     };
                     scope_vars_ptr.set_field(name.clone(), val);
                 }
-                Ok(Gc::new(VUndefined))
+                Ok(Gc::new(ValueData::Undefined))
             }
-            TypeOfExpr(ref val_e) => {
+            ExprDef::TypeOfExpr(ref val_e) => {
                 let val = try!(self.run(*val_e));
                 Ok(to_value(match *val.borrow() {
-                    VUndefined => "undefined",
+                    ValueData::Undefined => "undefined",
                     ValueData::Null | VObject(_) => "object",
                     VBoolean(_) => "boolean",
                     VNumber(_) | VInteger(_) => "number",
                     VString(_) => "string",
-                    VFunction(_) => "function",
+                    ValueData::Function(_) => "function",
                 }))
             }
         }
diff --git a/src/lib/js/array.rs b/src/lib/js/array.rs
index 02882b1ff2..53bd8eec1a 100644
--- a/src/lib/js/array.rs
+++ b/src/lib/js/array.rs
@@ -1,14 +1,15 @@
-use js::function::Function;
-use js::value::{to_value, ResultValue, Value};
+use gc::Gc;
+use js::value::{to_value, ResultValue, Value, ValueData};
 
 /// Create a new array
 pub fn make_array(_: Vec<Value>, _: Value, _: Value, this: Value) -> ResultValue {
-    this.set_field_slice("length", to_value(0i32));
-    Ok(Value::undefined())
+    let this_ptr = *this;
+    this_ptr.set_field_slice("length", to_value(0i32));
+    Ok(Gc::new(ValueData::Undefined))
 }
 /// Create a new `Array` object
 pub fn _create() -> Value {
-    let array = Function::make(make_array, &[]);
+    let array = to_value(make_array);
     array
 }
 /// Initialise the global object with the `Array` object
diff --git a/src/lib/js/console.rs b/src/lib/js/console.rs
index fe9361425b..80a09d9091 100644
--- a/src/lib/js/console.rs
+++ b/src/lib/js/console.rs
@@ -1,15 +1,13 @@
-use js::function::Function;
-use js::value::{from_value, ResultValue, Value};
+use gc::Gc;
+use js::value::{from_value, to_value, ResultValue, Value, ValueData};
 use std::iter::FromIterator;
 use time::{now, strftime};
 /// Print a javascript value to the standard output stream
-pub fn log(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
-    let args: Vec<String> = FromIterator::from_iter(
-        args.iter()
-            .map(|x| from_value::<String>(x.clone()).unwrap()),
-    );
+pub fn log(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
+    let args: Vec<String> =
+        FromIterator::from_iter(args.iter().map(|x| from_value::<String>(*x).unwrap()));
     println!("{}: {}", strftime("%X", &now()).unwrap(), args.join(" "));
-    Ok(Value::undefined())
+    Ok(Gc::new(ValueData::Undefined))
 }
 /// Print a javascript value to the standard error stream
 pub fn error(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
@@ -18,14 +16,14 @@ pub fn error(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
             .map(|x| from_value::<String>(x.clone()).unwrap()),
     );
     eprintln!("{}: {}", strftime("%X", &now()).unwrap(), args.join(" "));
-    Ok(Value::undefined())
+    Ok(Gc::new(ValueData::Undefined))
 }
 /// Create a new `console` object
 pub fn _create(global: Value) -> Value {
-    let console = Value::new_obj(Some(global));
-    console.set_field_slice("log", Function::make(log, &["object"]));
-    console.set_field_slice("error", Function::make(error, &["error"]));
-    console.set_field_slice("exception", Function::make(error, &["error"]));
+    let console = ValueData::new_obj(Some(global));
+    console.set_field_slice("log", to_value(log));
+    console.set_field_slice("error", to_value(error));
+    console.set_field_slice("exception", to_value(error));
     console
 }
 /// Initialise the global object with the `console` object
diff --git a/src/lib/js/function.rs b/src/lib/js/function.rs
index 46c3707146..bf387aade8 100644
--- a/src/lib/js/function.rs
+++ b/src/lib/js/function.rs
@@ -4,7 +4,6 @@ use js::value::{to_value, ResultValue, Value, ValueData};
 use std::collections::HashMap;
 use syntax::ast::expr::Expr;
 
-pub type FunctionData = fn(Vec<Value>, Value, Value, Value) -> ResultValue;
 pub type NativeFunctionData = fn(Value, Value, Vec<Value>) -> ResultValue;
 /// A Javascript function
 /// A member of the Object type that may be invoked as a subroutine
@@ -12,7 +11,7 @@ pub type NativeFunctionData = fn(Value, Value, Vec<Value>) -> ResultValue;
 /// In our implementation, Function is extending Object by holding an object field which some extra data
 
 /// A Javascript function
-#[derive(Trace, Finalize, Debug)]
+#[derive(Trace, Finalize, Debug, Clone)]
 pub enum Function {
     /// A native javascript function
     NativeFunc(NativeFunction),
@@ -21,7 +20,7 @@ pub enum Function {
 }
 
 /// Represents a regular javascript function in memory
-#[derive(Trace, Finalize, Debug)]
+#[derive(Trace, Finalize, Debug, Clone)]
 pub struct RegularFunction {
     /// The fields associated with the function
     pub object: ObjectData,
@@ -47,7 +46,7 @@ impl RegularFunction {
     }
 }
 
-#[derive(Trace, Finalize, Debug)]
+#[derive(Trace, Finalize, Debug, Clone)]
 /// Represents a native javascript function in memory
 pub struct NativeFunction {
     /// The fields associated with the function
@@ -73,6 +72,6 @@ pub fn _create() -> Value {
 }
 /// Initialise the global object with the `Function` object
 pub fn init(global: Value) {
-    let global_ptr = global.borrow();
-    global_ptr.set_field_slice("Function", _create(global));
+    let global_ptr = &global;
+    global_ptr.set_field_slice("Function", _create());
 }
diff --git a/src/lib/js/json.rs b/src/lib/js/json.rs
index b7494c9882..f11ec34439 100644
--- a/src/lib/js/json.rs
+++ b/src/lib/js/json.rs
@@ -1,19 +1,19 @@
 use js::function::Function;
 /// The JSON Object
 /// https://tc39.github.io/ecma262/#sec-json-object
-use js::value::{to_value, ResultValue, Value};
+use js::value::{to_value, ResultValue, Value, ValueData};
 use serde_json::{self, to_string_pretty, Value as JSONValue};
 
 /// Parse a JSON string into a Javascript object
 /// https://tc39.github.io/ecma262/#sec-json.parse
-pub fn parse(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn parse(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     match serde_json::from_str::<JSONValue>(&args.get(0).unwrap().clone().to_string()) {
         Ok(json) => Ok(to_value(json)),
         Err(err) => Err(to_value(err.to_string())),
     }
 }
 /// Process a Javascript object into a JSON string
-pub fn stringify(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn stringify(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let obj = args.get(0).unwrap();
     let json = obj.to_json();
     Ok(to_value(to_string_pretty(&json).unwrap()))
@@ -21,9 +21,9 @@ pub fn stringify(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue
 
 /// Create a new `JSON` object
 pub fn _create(global: Value) -> Value {
-    let object = Value::new_obj(Some(global));
-    object.set_field_slice("stringify", Function::make(stringify, &["JSON"]));
-    object.set_field_slice("parse", Function::make(parse, &["JSON_string"]));
+    let object = ValueData::new_obj(Some(global));
+    object.set_field_slice("stringify", to_value(stringify));
+    object.set_field_slice("parse", to_value(parse));
     object
 }
 
diff --git a/src/lib/js/math.rs b/src/lib/js/math.rs
index c00b7728e8..52e61ab8d2 100644
--- a/src/lib/js/math.rs
+++ b/src/lib/js/math.rs
@@ -4,7 +4,7 @@ use rand::random;
 use std::f64;
 
 /// Get the absolute value of a number
-pub fn abs(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn abs(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -14,7 +14,7 @@ pub fn abs(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the arccos of a number
-pub fn acos(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn acos(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -24,7 +24,7 @@ pub fn acos(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the arcsine of a number
-pub fn asin(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn asin(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -34,7 +34,7 @@ pub fn asin(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the arctangent of a number
-pub fn atan(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn atan(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -44,7 +44,7 @@ pub fn atan(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the arctangent of a numbers
-pub fn atan2(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn atan2(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -54,7 +54,7 @@ pub fn atan2(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the cubic root of a number
-pub fn cbrt(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn cbrt(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -64,7 +64,7 @@ pub fn cbrt(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get lowest integer above a number
-pub fn ceil(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn ceil(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -74,7 +74,7 @@ pub fn ceil(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the cosine of a number
-pub fn cos(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn cos(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -84,7 +84,7 @@ pub fn cos(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the power to raise the natural logarithm to get the number
-pub fn exp(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn exp(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -94,7 +94,7 @@ pub fn exp(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the highest integer below a number
-pub fn floor(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn floor(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -104,7 +104,7 @@ pub fn floor(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the natural logarithm of a number
-pub fn log(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn log(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -114,7 +114,7 @@ pub fn log(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the maximum of several numbers
-pub fn max(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn max(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let mut max = f64::NEG_INFINITY;
     for arg in args.iter() {
         let num = arg.to_num();
@@ -123,7 +123,7 @@ pub fn max(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     Ok(to_value(max))
 }
 /// Get the minimum of several numbers
-pub fn min(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn min(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let mut max = f64::INFINITY;
     for arg in args.iter() {
         let num = arg.to_num();
@@ -132,7 +132,7 @@ pub fn min(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     Ok(to_value(max))
 }
 /// Raise a number to a power
-pub fn pow(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn pow(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 2 {
         let num: f64 = from_value(args.get(0).unwrap().clone()).unwrap();
         let power: f64 = from_value(args.get(1).unwrap().clone()).unwrap();
@@ -146,7 +146,7 @@ pub fn _random(_: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     Ok(to_value(random::<f64>()))
 }
 /// Round a number to the nearest integer
-pub fn round(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn round(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -156,7 +156,7 @@ pub fn round(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the sine of a number
-pub fn sin(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn sin(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -166,7 +166,7 @@ pub fn sin(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the square root of a number
-pub fn sqrt(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn sqrt(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -176,7 +176,7 @@ pub fn sqrt(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
     }))
 }
 /// Get the tangent of a number
-pub fn tan(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn tan(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     Ok(to_value(if args.len() >= 1 {
         from_value::<f64>(args.get(0).unwrap().clone())
             .unwrap()
@@ -196,25 +196,25 @@ pub fn _create(global: Value) -> Value {
     math.set_field_slice("SQRT1_2", to_value(0.5f64.sqrt()));
     math.set_field_slice("SQRT2", to_value(f64::consts::SQRT_2));
     math.set_field_slice("PI", to_value(f64::consts::PI));
-    math.set_field_slice("abs", Function::make(abs, &["num1", "num2"]));
-    math.set_field_slice("acos", Function::make(acos, &["num1", "num2"]));
-    math.set_field_slice("asin", Function::make(asin, &["num1", "num2"]));
-    math.set_field_slice("atan", Function::make(atan, &["num1", "num2"]));
-    math.set_field_slice("atan2", Function::make(atan2, &["num1", "num2"]));
-    math.set_field_slice("cbrt", Function::make(cbrt, &["num1", "num2"]));
-    math.set_field_slice("ceil", Function::make(ceil, &["num1", "num2"]));
-    math.set_field_slice("cos", Function::make(cos, &["num1", "num2"]));
-    math.set_field_slice("exp", Function::make(exp, &["num1", "num2"]));
-    math.set_field_slice("floor", Function::make(floor, &["num"]));
-    math.set_field_slice("log", Function::make(log, &["num1", "num2"]));
-    math.set_field_slice("max", Function::make(max, &["num1", "num2"]));
-    math.set_field_slice("min", Function::make(min, &["num1", "num2"]));
-    math.set_field_slice("pow", Function::make(pow, &["num1", "num2"]));
-    math.set_field_slice("random", Function::make(_random, &[]));
-    math.set_field_slice("round", Function::make(round, &["num"]));
-    math.set_field_slice("sin", Function::make(sin, &["num"]));
-    math.set_field_slice("sqrt", Function::make(sqrt, &["num"]));
-    math.set_field_slice("tan", Function::make(tan, &["num"]));
+    math.set_field_slice("abs", to_value(abs));
+    math.set_field_slice("acos", to_value(acos));
+    math.set_field_slice("asin", to_value(asin));
+    math.set_field_slice("atan", to_value(atan));
+    math.set_field_slice("atan2", to_value(atan2));
+    math.set_field_slice("cbrt", to_value(cbrt));
+    math.set_field_slice("ceil", to_value(ceil));
+    math.set_field_slice("cos", to_value(cos));
+    math.set_field_slice("exp", to_value(exp));
+    math.set_field_slice("floor", to_value(floor, &["num"]));
+    math.set_field_slice("log", to_value(log));
+    math.set_field_slice("max", to_value(max));
+    math.set_field_slice("min", to_value(min));
+    math.set_field_slice("pow", to_value(pow));
+    math.set_field_slice("random", to_value(_random));
+    math.set_field_slice("round", to_value(round));
+    math.set_field_slice("sin", to_value(sin));
+    math.set_field_slice("sqrt", to_value(sqrt));
+    math.set_field_slice("tan", to_value(tan));
     math
 }
 /// Initialise the `Math` object on the global object
diff --git a/src/lib/js/object.rs b/src/lib/js/object.rs
index e78f22b2d9..d1f0baeb8c 100644
--- a/src/lib/js/object.rs
+++ b/src/lib/js/object.rs
@@ -1,5 +1,5 @@
-use js::function::Function;
-use js::value::{from_value, to_value, FromValue, ResultValue, ToValue, Value};
+use gc::Gc;
+use js::value::{from_value, to_value, FromValue, ResultValue, ToValue, Value, ValueData};
 use std::collections::HashMap;
 pub static PROTOTYPE: &'static str = "prototype";
 pub static INSTANCE_PROTOTYPE: &'static str = "__proto__";
@@ -33,15 +33,15 @@ impl Property {
             enumerable: false,
             writable: false,
             value: value,
-            get: Value::undefined(),
-            set: Value::undefined(),
+            get: Gc::new(ValueData::Undefined),
+            set: Gc::new(ValueData::Undefined),
         }
     }
 }
 
 impl ToValue for Property {
     fn to_value(&self) -> Value {
-        let prop = Value::new_obj(None);
+        let prop = ValueData::new_obj(None);
         prop.set_field_slice("configurable", to_value(self.configurable));
         prop.set_field_slice("enumerable", to_value(self.enumerable));
         prop.set_field_slice("writable", to_value(self.writable));
@@ -67,17 +67,17 @@ impl FromValue for Property {
 
 /// Create a new object
 pub fn make_object(_: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
-    Ok(Value::undefined())
+    Ok(Gc::new(ValueData::Undefined))
 }
 
 /// Get the prototype of an object
-pub fn get_proto_of(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn get_proto_of(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let obj = args.get(0).unwrap();
     Ok(obj.get_field_slice(INSTANCE_PROTOTYPE))
 }
 
 /// Set the prototype of an object
-pub fn set_proto_of(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn set_proto_of(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let obj = args.get(0).unwrap().clone();
     let proto = args.get(1).unwrap().clone();
     obj.set_field_slice(INSTANCE_PROTOTYPE, proto);
@@ -85,21 +85,21 @@ pub fn set_proto_of(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultVal
 }
 
 /// Define a property in an object
-pub fn define_prop(args: Vec<Value>, _: Value, _: Value, _: Value) -> ResultValue {
+pub fn define_prop(_: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let obj = args.get(0).unwrap();
     let prop = from_value::<String>(args.get(1).unwrap().clone()).unwrap();
     let desc = from_value::<Property>(args.get(2).unwrap().clone()).unwrap();
     obj.set_prop(prop, desc);
-    Ok(Value::undefined())
+    Ok(Gc::new(ValueData::Undefined))
 }
 
 /// To string
-pub fn to_string(_: Vec<Value>, _: Value, _: Value, this: Value) -> ResultValue {
+pub fn to_string(this: Value, _: Value, _: Vec<Value>) -> ResultValue {
     Ok(to_value(this.to_string()))
 }
 
 /// Check if it has a property
-pub fn has_own_prop(args: Vec<Value>, _: Value, _: Value, this: Value) -> ResultValue {
+pub fn has_own_prop(this: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let prop = if args.len() == 0 {
         None
     } else {
@@ -112,24 +112,16 @@ pub fn has_own_prop(args: Vec<Value>, _: Value, _: Value, this: Value) -> Result
 
 /// Create a new `Object` object
 pub fn _create(global: Value) -> Value {
-    let object = Function::make(make_object, &[]);
-    let prototype = Value::new_obj(Some(global));
-    prototype.set_field_slice(
-        "hasOwnProperty",
-        Function::make(has_own_prop, &["property"]),
-    );
-    prototype.set_field_slice("toString", Function::make(to_string, &[]));
-    object.set_field_slice("length", to_value(1i32));
-    object.set_field_slice(PROTOTYPE, prototype);
-    object.set_field_slice(
-        "setPrototypeOf",
-        Function::make(get_proto_of, &["object", "prototype"]),
-    );
-    object.set_field_slice("getPrototypeOf", Function::make(get_proto_of, &["object"]));
-    object.set_field_slice(
-        "defineProperty",
-        Function::make(define_prop, &["object", "property"]),
-    );
+    let object = to_value(make_object);
+    let object_ptr = object;
+    let prototype = ValueData::new_obj(Some(global));
+    prototype.set_field_slice("hasOwnProperty", to_value(has_own_prop));
+    prototype.set_field_slice("toString", to_value(to_string));
+    object_ptr.set_field_slice("length", to_value(1i32));
+    object_ptr.set_field_slice(PROTOTYPE, prototype);
+    object_ptr.set_field_slice("setPrototypeOf", to_value(set_proto_of));
+    object_ptr.set_field_slice("getPrototypeOf", to_value(get_proto_of));
+    object_ptr.set_field_slice("defineProperty", to_value(define_prop));
     object
 }
 
diff --git a/src/lib/js/string.rs b/src/lib/js/string.rs
index 3c9eff16d9..713f3984d1 100644
--- a/src/lib/js/string.rs
+++ b/src/lib/js/string.rs
@@ -1,28 +1,29 @@
+use gc::Gc;
 use js::function::Function;
 use js::object::{Property, PROTOTYPE};
-use js::value::{from_value, to_value, ResultValue, Value};
+use js::value::{from_value, to_value, ResultValue, Value, ValueData};
 
 /// Create new string
-pub fn make_string(_: Vec<Value>, _: Value, _: Value, this: Value) -> ResultValue {
+pub fn make_string(this: Value, _: Value, _: Vec<Value>) -> ResultValue {
     this.set_field_slice("length", to_value(0i32));
-    Ok(Value::undefined())
+    Ok(Gc::new(ValueData::Undefined))
 }
 /// Get a string's length
-pub fn get_string_length(_: Vec<Value>, _: Value, _: Value, this: Value) -> ResultValue {
+pub fn get_string_length(this: Value, _: Value, _: Vec<Value>) -> ResultValue {
     let this_str: String = from_value(this).unwrap();
     Ok(to_value::<i32>(this_str.len() as i32))
 }
 /// Create a new `String` object
 pub fn _create(global: Value) -> Value {
-    let string = Function::make(make_string, &["string"]);
-    let proto = Value::new_obj(Some(global));
+    let string = to_value(make_string);
+    let proto = ValueData::new_obj(Some(global));
     let prop = Property {
         configurable: false,
         enumerable: false,
         writable: false,
-        value: Value::undefined(),
-        get: Function::make(get_string_length, &[]),
-        set: Value::undefined(),
+        value: Gc::new(ValueData::Undefined),
+        get: to_value(get_string_length),
+        set: Gc::new(ValueData::Undefined),
     };
     proto.set_prop_slice("length", prop);
     string.set_field_slice(PROTOTYPE, proto);
diff --git a/src/lib/js/value.rs b/src/lib/js/value.rs
index e1e8fc6e4d..515276f713 100644
--- a/src/lib/js/value.rs
+++ b/src/lib/js/value.rs
@@ -1,17 +1,20 @@
 use gc::{Gc, GcCell};
-use js::function::Function;
+use js::function::{Function, NativeFunction, NativeFunctionData};
 use js::object::{ObjectData, Property, INSTANCE_PROTOTYPE, PROTOTYPE};
 use serde_json::map::Map;
 use serde_json::Number as JSONNumber;
 use serde_json::Value as JSONValue;
 use std::collections::HashMap;
 use std::f64::NAN;
+use std::fmt;
 use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::iter::FromIterator;
 use std::ops::Deref;
 use std::ops::DerefMut;
+use std::ops::{Add, BitAnd, BitOr, BitXor, Div, Mul, Not, Rem, Shl, Shr, Sub};
 use std::str::FromStr;
 
+#[must_use]
 /// The result of a Javascript expression is represented like this so it can succeed (`Ok`) or fail (`Err`)
 pub type ResultValue = Result<Value, Value>;
 /// A Garbage-collected Javascript value as represented in the interpreter
@@ -295,7 +298,7 @@ impl ValueData {
 }
 
 impl Display for ValueData {
-    fn fmt(&self, f: &mut Formatter) -> FmtResult {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             ValueData::Null => write!(f, "null"),
             ValueData::Undefined => write!(f, "undefined"),
@@ -305,10 +308,9 @@ impl Display for ValueData {
                 f,
                 "{}",
                 match v {
-                    // https://tc39.github.io/ecma262/#sec-tostring-applied-to-the-number-type
                     _ if v.is_nan() => "NaN".to_string(),
-                    _ if v.is_infinite() && v.is_sign_positive() => "Infinity".to_string(),
-                    _ if v.is_infinite() && v.is_sign_negative() => "-Infinity".to_string(),
+                    std::f64::INFINITY => "Infinity".to_string(),
+                    std::f64::NEG_INFINITY => "-Infinity".to_string(),
                     _ => v.to_string(),
                 }
             ),
@@ -317,7 +319,7 @@ impl Display for ValueData {
                 match v.borrow().iter().last() {
                     Some((last_key, _)) => {
                         for (key, val) in v.borrow().iter() {
-                            try!(write!(f, "{}: {}", key, val.value));
+                            try!(write!(f, "{}: {}", key, val.value.clone()));
                             if key != last_key {
                                 try!(write!(f, "{}", ", "));
                             }
@@ -328,13 +330,18 @@ impl Display for ValueData {
                 write!(f, "{}", "}")
             }
             ValueData::Integer(v) => write!(f, "{}", v),
-            ValueData::Function(ref v) => write!(f, "function({})", v.borrow().args.join(", ")),
+            ValueData::Function(ref v) => match *v.borrow() {
+                Function::NativeFunc(_) => write!(f, "{}", "function() { [native code] }"),
+                Function::RegularFunc(rf) => {
+                    write!(f, "function({}){}", rf.args.join(", "), rf.expr)
+                }
+            },
         }
     }
 }
 
-impl PartialEq for Value {
-    fn eq(&self, other: &Value) -> bool {
+impl PartialEq for ValueData {
+    fn eq(&self, other: &ValueData) -> bool {
         match (self.clone().deref(), other.clone().deref()) {
             // TODO: fix this
             // _ if self.ptr.to_inner() == &other.ptr.to_inner() => true,
@@ -356,6 +363,68 @@ impl PartialEq for Value {
     }
 }
 
+impl Add for ValueData {
+    type Output = ValueData;
+    fn add(self, other: ValueData) -> ValueData {
+        return match (self, other) {
+            (ValueData::String(s), other) | (other, ValueData::String(s)) => {
+                ValueData::String(s.clone().append(other.to_string()))
+            }
+            (_, _) => ValueData::Number(self.to_num() + other.to_num()),
+        };
+    }
+}
+impl Sub for ValueData {
+    fn sub(&self, other: &ValueData) -> ValueData {
+        ValueData::Number(self.to_num() - other.to_num())
+    }
+}
+impl Mul for ValueData {
+    fn mul(&self, other: &ValueData) -> ValueData {
+        ValueData::Number(self.to_num() * other.to_num())
+    }
+}
+impl Div for ValueData {
+    fn div(&self, other: &ValueData) -> ValueData {
+        ValueData::Number(self.to_num() / other.to_num())
+    }
+}
+impl Rem for ValueData {
+    fn rem(&self, other: ValueData) -> ValueData {
+        ValueData::Number(self.to_num() % other.to_num())
+    }
+}
+impl BitAnd for ValueData {
+    fn bitand(&self, other: ValueData) -> ValueData {
+        ValueData::Integer(self.to_int() & other.to_int())
+    }
+}
+impl BitOr for ValueData {
+    fn bitor(&self, other: &ValueData) -> ValueData {
+        ValueData::Integer(self.to_int() | other.to_int())
+    }
+}
+impl BitXor for ValueData {
+    fn bitxor(&self, other: &ValueData) -> ValueData {
+        ValueData::Integer(self.to_int() ^ other.to_int())
+    }
+}
+impl Shl for ValueData {
+    fn shl(&self, other: &ValueData) -> ValueData {
+        ValueData::Integer(self.to_int() << other.to_int())
+    }
+}
+impl Shr for ValueData {
+    fn shr(&self, other: &ValueData) -> ValueData {
+        ValueData::Integer(self.to_int() >> other.to_int())
+    }
+}
+impl Not for ValueData {
+    fn not(&self) -> ValueData {
+        ValueData::Boolean(!self.is_true())
+    }
+}
+
 /// Conversion to Javascript values from Rust values
 pub trait ToValue {
     /// Convert this value to a Rust value
@@ -371,7 +440,7 @@ pub trait FromValue {
 
 impl ToValue for String {
     fn to_value(&self) -> Value {
-        Gc::new(ValueData::String(self.clone())),
+        Gc::new(ValueData::String(self.clone()))
     }
 }
 
@@ -383,17 +452,13 @@ impl FromValue for String {
 
 impl<'s> ToValue for &'s str {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::String(String::from_str(*self).unwrap())),
-        }
+        Gc::new(ValueData::String(String::from_str(*self).unwrap()))
     }
 }
 
 impl ToValue for char {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::String(self.to_string())),
-        }
+        Gc::new(ValueData::String(self.to_string()))
     }
 }
 impl FromValue for char {
@@ -404,9 +469,7 @@ impl FromValue for char {
 
 impl ToValue for f64 {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::Number(*self)),
-        }
+        Gc::new(ValueData::Number(*self))
     }
 }
 impl FromValue for f64 {
@@ -417,9 +480,7 @@ impl FromValue for f64 {
 
 impl ToValue for i32 {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::Integer(*self)),
-        }
+        Gc::new(ValueData::Integer(*self))
     }
 }
 impl FromValue for i32 {
@@ -430,9 +491,7 @@ impl FromValue for i32 {
 
 impl ToValue for bool {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::Boolean(*self)),
-        }
+        Gc::new(ValueData::Boolean(*self))
     }
 }
 impl FromValue for bool {
@@ -477,19 +536,18 @@ impl<T: FromValue> FromValue for Vec<T> {
 
 impl ToValue for ObjectData {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::Object(GcCell::new(self.clone()))),
-        }
+        Gc::new(ValueData::Object(GcCell::new(self.clone())))
     }
 }
+
 impl FromValue for ObjectData {
     fn from_value(v: Value) -> Result<ObjectData, &'static str> {
-        match *v.ptr {
-            ValueData::Object(ref obj) => {
-                let obj_data = obj.clone().into_inner();
-                Ok(obj_data)
-            }
-            ValueData::Function(ref func) => Ok(func.borrow().object.clone()),
+        match *v {
+            ValueData::Object(ref obj) => Ok(obj.clone().borrow().deref().clone()),
+            ValueData::Function(ref func) => Ok(match *func.borrow().deref() {
+                Function::NativeFunc(ref data) => data.object.clone(),
+                Function::RegularFunc(ref data) => data.object.clone(),
+            }),
             _ => Err("Value is not a valid object"),
         }
     }
@@ -497,11 +555,10 @@ impl FromValue for ObjectData {
 
 impl ToValue for JSONValue {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(Value::from_json(self.clone())),
-        }
+        Gc::new(ValueData::from_json(self.clone()))
     }
 }
+
 impl FromValue for JSONValue {
     fn from_value(v: Value) -> Result<JSONValue, &'static str> {
         Ok(v.to_json())
@@ -510,9 +567,7 @@ impl FromValue for JSONValue {
 
 impl ToValue for () {
     fn to_value(&self) -> Value {
-        Value {
-            ptr: Gc::new(ValueData::Null),
-        }
+        Gc::new(ValueData::Null)
     }
 }
 impl FromValue for () {
@@ -525,9 +580,7 @@ impl<T: ToValue> ToValue for Option<T> {
     fn to_value(&self) -> Value {
         match *self {
             Some(ref v) => v.to_value(),
-            None => Value {
-                ptr: Gc::new(ValueData::Null),
-            },
+            None => Gc::new(ValueData::Null),
         }
     }
 }
@@ -541,6 +594,25 @@ impl<T: FromValue> FromValue for Option<T> {
     }
 }
 
+impl ToValue for NativeFunctionData {
+    fn to_value(&self) -> Value {
+        Gc::new(ValueData::Function(GcCell::new(Function::NativeFunc(
+            NativeFunction::new(*self),
+        ))))
+    }
+}
+impl FromValue for NativeFunctionData {
+    fn from_value(v: Value) -> Result<NativeFunctionData, &'static str> {
+        match *v {
+            ValueData::Function(ref func) => match *func.borrow() {
+                Function::NativeFunc(ref data) => Ok(data.data),
+                _ => Err("Value is not a native function"),
+            },
+            _ => Err("Value is not a function"),
+        }
+    }
+}
+
 /// A utility function that just calls FromValue::from_value
 pub fn from_value<A: FromValue>(v: Value) -> Result<A, &'static str> {
     FromValue::from_value(v)
diff --git a/src/lib/syntax/ast/constant.rs b/src/lib/syntax/ast/constant.rs
index 747803d8c2..175739c5fe 100644
--- a/src/lib/syntax/ast/constant.rs
+++ b/src/lib/syntax/ast/constant.rs
@@ -1,6 +1,6 @@
 use std::fmt::{Display, Formatter, Result};
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A Javascript Constant
 pub enum Const {
     /// A UTF-8 string, such as `"Hello, world"`
diff --git a/src/lib/syntax/ast/expr.rs b/src/lib/syntax/ast/expr.rs
index e686cdd480..1687d15170 100644
--- a/src/lib/syntax/ast/expr.rs
+++ b/src/lib/syntax/ast/expr.rs
@@ -3,7 +3,7 @@ use std::fmt::{Display, Formatter, Result};
 use syntax::ast::constant::Const;
 use syntax::ast::op::{BinOp, Operator, UnaryOp};
 
-#[derive(Clone, Trace, Debug, PartialEq)]
+#[derive(Clone, Trace, Finalize, Debug, PartialEq)]
 pub struct Expr {
     /// The expression definition
     pub def: ExprDef,
@@ -22,7 +22,7 @@ impl Display for Expr {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A Javascript Expression
 pub enum ExprDef {
     /// Run a operation between 2 expressions
diff --git a/src/lib/syntax/ast/op.rs b/src/lib/syntax/ast/op.rs
index cd05b35be5..a9c634e278 100644
--- a/src/lib/syntax/ast/op.rs
+++ b/src/lib/syntax/ast/op.rs
@@ -12,7 +12,7 @@ pub trait Operator {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A numeric operation between 2 values
 pub enum NumOp {
     /// `a + b` - Addition
@@ -43,7 +43,7 @@ impl Display for NumOp {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A unary operation on a single value
 pub enum UnaryOp {
     /// `a++` - increment the value
@@ -78,7 +78,7 @@ impl Display for UnaryOp {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A bitwise operation between 2 values
 pub enum BitOp {
     /// `a & b` - Bitwise and
@@ -109,7 +109,7 @@ impl Display for BitOp {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A comparitive operation between 2 values
 pub enum CompOp {
     /// `a == b` - Equality
@@ -149,7 +149,7 @@ impl Display for CompOp {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A logical operation between 2 boolean values
 pub enum LogOp {
     /// `a && b` - Logical and
@@ -171,7 +171,7 @@ impl Display for LogOp {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
 /// A binary operation between 2 values
 pub enum BinOp {
     /// Numeric operation