diff --git a/bug_test.go b/bug_test.go
index 0dd1b01..7c072c8 100644
--- a/bug_test.go
+++ b/bug_test.go
@@ -55,7 +55,7 @@ func Test_issue13(t *testing.T) {
 			t.Error(err)
 			t.FailNow()
 		}
-		is(result.toString(), "Xyzzy,42,def,ghi")
+		is(result.string(), "Xyzzy,42,def,ghi")
 
 		anything := struct {
 			Abc interface{}
diff --git a/builtin.go b/builtin.go
index 7e911bd..9562e86 100644
--- a/builtin.go
+++ b/builtin.go
@@ -18,7 +18,7 @@ func builtinGlobal_eval(call FunctionCall) Value {
 		return src
 	}
 	runtime := call.runtime
-	program := runtime.cmpl_parseOrThrow(toString(src))
+	program := runtime.cmpl_parseOrThrow(src.string())
 	if !call.eval {
 		// Not a direct call to eval, so we enter the global ExecutionContext
 		runtime.enterGlobalScope()
@@ -32,12 +32,12 @@ func builtinGlobal_eval(call FunctionCall) Value {
 }
 
 func builtinGlobal_isNaN(call FunctionCall) Value {
-	value := toFloat(call.Argument(0))
+	value := call.Argument(0).float64()
 	return toValue_bool(math.IsNaN(value))
 }
 
 func builtinGlobal_isFinite(call FunctionCall) Value {
-	value := toFloat(call.Argument(0))
+	value := call.Argument(0).float64()
 	return toValue_bool(!math.IsNaN(value) && !math.IsInf(value, 0))
 }
 
@@ -70,7 +70,7 @@ func digitValue(chr rune) int {
 }
 
 func builtinGlobal_parseInt(call FunctionCall) Value {
-	input := strings.TrimSpace(toString(call.Argument(0)))
+	input := strings.TrimSpace(call.Argument(0).string())
 	if len(input) == 0 {
 		return NaNValue()
 	}
@@ -153,7 +153,7 @@ var parseFloat_matchValid = regexp.MustCompile(`[0-9eE\+\-\.]|Infinity`)
 
 func builtinGlobal_parseFloat(call FunctionCall) Value {
 	// Caveat emptor: This implementation does NOT match the specification
-	input := strings.TrimSpace(toString(call.Argument(0)))
+	input := strings.TrimSpace(call.Argument(0).string())
 	if parseFloat_matchBadSpecial.MatchString(input) {
 		return NaNValue()
 	}
@@ -185,7 +185,7 @@ func _builtinGlobal_encodeURI(call FunctionCall, escape *regexp.Regexp) Value {
 	case []uint16:
 		input = vl
 	default:
-		input = utf16.Encode([]rune(toString(value)))
+		input = utf16.Encode([]rune(value.string()))
 	}
 	if len(input) == 0 {
 		return toValue_string("")
@@ -256,7 +256,7 @@ func _decodeURI(input string, reserve bool) (string, bool) {
 }
 
 func builtinGlobal_decodeURI(call FunctionCall) Value {
-	output, err := _decodeURI(toString(call.Argument(0)), true)
+	output, err := _decodeURI(call.Argument(0).string(), true)
 	if err {
 		panic(newURIError("URI malformed"))
 	}
@@ -264,7 +264,7 @@ func builtinGlobal_decodeURI(call FunctionCall) Value {
 }
 
 func builtinGlobal_decodeURIComponent(call FunctionCall) Value {
-	output, err := _decodeURI(toString(call.Argument(0)), false)
+	output, err := _decodeURI(call.Argument(0).string(), false)
 	if err {
 		panic(newURIError("URI malformed"))
 	}
@@ -345,9 +345,9 @@ func builtin_unescape(input string) string {
 }
 
 func builtinGlobal_escape(call FunctionCall) Value {
-	return toValue_string(builtin_escape(toString(call.Argument(0))))
+	return toValue_string(builtin_escape(call.Argument(0).string()))
 }
 
 func builtinGlobal_unescape(call FunctionCall) Value {
-	return toValue_string(builtin_unescape(toString(call.Argument(0))))
+	return toValue_string(builtin_unescape(call.Argument(0).string()))
 }
diff --git a/builtin_array.go b/builtin_array.go
index 26eb37c..87af242 100644
--- a/builtin_array.go
+++ b/builtin_array.go
@@ -54,7 +54,7 @@ func builtinArray_toLocaleString(call FunctionCall) Value {
 			if !toLocaleString.isCallable() {
 				panic(newTypeError())
 			}
-			stringValue = toLocaleString.call(toValue_object(object)).toString()
+			stringValue = toLocaleString.call(toValue_object(object)).string()
 		}
 		stringList = append(stringList, stringValue)
 	}
@@ -70,7 +70,7 @@ func builtinArray_concat(call FunctionCall) Value {
 		case valueObject:
 			object := item._object()
 			if isArray(object) {
-				length := toInteger(object.get("length")).int64
+				length := object.get("length").number().int64
 				for index := int64(0); index < length; index += 1 {
 					name := strconv.FormatInt(index, 10)
 					if object.hasProperty(name) {
@@ -143,7 +143,7 @@ func builtinArray_join(call FunctionCall) Value {
 	{
 		argument := call.Argument(0)
 		if argument.IsDefined() {
-			separator = toString(argument)
+			separator = argument.string()
 		}
 	}
 	thisObject := call.thisObject()
@@ -158,7 +158,7 @@ func builtinArray_join(call FunctionCall) Value {
 		switch value.kind {
 		case valueEmpty, valueUndefined, valueNull:
 		default:
-			stringValue = toString(value)
+			stringValue = value.string()
 		}
 		stringList = append(stringList, stringValue)
 	}
@@ -370,8 +370,8 @@ func sortCompare(thisObject *_object, index0, index1 uint, compare *_object) int
 	}
 
 	if compare == nil {
-		j.value = toString(x)
-		k.value = toString(y)
+		j.value = x.string()
+		k.value = y.string()
 
 		if j.value == k.value {
 			return 0
@@ -464,7 +464,7 @@ func builtinArray_indexOf(call FunctionCall) Value {
 	if length := int64(toUint32(thisObject.get("length"))); length > 0 {
 		index := int64(0)
 		if len(call.ArgumentList) > 1 {
-			index = toInteger(call.Argument(1)).int64
+			index = call.Argument(1).number().int64
 		}
 		if index < 0 {
 			if index += length; index < 0 {
@@ -492,7 +492,7 @@ func builtinArray_lastIndexOf(call FunctionCall) Value {
 	length := int64(toUint32(thisObject.get("length")))
 	index := length - 1
 	if len(call.ArgumentList) > 1 {
-		index = toInteger(call.Argument(1)).int64
+		index = call.Argument(1).number().int64
 	}
 	if 0 > index {
 		index += length
@@ -523,7 +523,7 @@ func builtinArray_every(call FunctionCall) Value {
 		callThis := call.Argument(1)
 		for index := int64(0); index < length; index++ {
 			if key := arrayIndexToString(index); thisObject.hasProperty(key) {
-				if value := thisObject.get(key); iterator.call(callThis, value, toValue_int64(index), this).isTrue() {
+				if value := thisObject.get(key); iterator.call(callThis, value, toValue_int64(index), this).bool() {
 					continue
 				}
 				return falseValue
@@ -542,7 +542,7 @@ func builtinArray_some(call FunctionCall) Value {
 		callThis := call.Argument(1)
 		for index := int64(0); index < length; index++ {
 			if key := arrayIndexToString(index); thisObject.hasProperty(key) {
-				if value := thisObject.get(key); iterator.call(callThis, value, toValue_int64(index), this).isTrue() {
+				if value := thisObject.get(key); iterator.call(callThis, value, toValue_int64(index), this).bool() {
 					return trueValue
 				}
 			}
@@ -597,7 +597,7 @@ func builtinArray_filter(call FunctionCall) Value {
 		for index := int64(0); index < length; index++ {
 			if key := arrayIndexToString(index); thisObject.hasProperty(key) {
 				value := thisObject.get(key)
-				if iterator.call(callThis, value, index, this).isTrue() {
+				if iterator.call(callThis, value, index, this).bool() {
 					values = append(values, value)
 				}
 			}
diff --git a/builtin_boolean.go b/builtin_boolean.go
index bedfe26..59b8e78 100644
--- a/builtin_boolean.go
+++ b/builtin_boolean.go
@@ -3,7 +3,7 @@ package otto
 // Boolean
 
 func builtinBoolean(call FunctionCall) Value {
-	return toValue_bool(toBoolean(call.Argument(0)))
+	return toValue_bool(call.Argument(0).bool())
 }
 
 func builtinNewBoolean(self *_object, argumentList []Value) Value {
@@ -16,7 +16,7 @@ func builtinBoolean_toString(call FunctionCall) Value {
 		// Will throw a TypeError if ThisObject is not a Boolean
 		value = call.thisClassObject("Boolean").primitiveValue()
 	}
-	return toValue_string(toString(value))
+	return toValue_string(value.string())
 }
 
 func builtinBoolean_valueOf(call FunctionCall) Value {
diff --git a/builtin_date.go b/builtin_date.go
index 444bb76..a31c3e0 100644
--- a/builtin_date.go
+++ b/builtin_date.go
@@ -69,7 +69,7 @@ func builtinDate_toJSON(call FunctionCall) Value {
 	object := call.thisObject()
 	value := object.DefaultValue(defaultValueHintNumber) // FIXME object.primitiveNumberValue
 	{                                                    // FIXME value.isFinite
-		value := toFloat(value)
+		value := value.float64()
 		if math.IsNaN(value) || math.IsInf(value, 0) {
 			return nullValue
 		}
@@ -102,7 +102,7 @@ func builtinDate_getTime(call FunctionCall) Value {
 func builtinDate_setTime(call FunctionCall) Value {
 	object := call.thisObject()
 	date := dateObjectOf(object)
-	date.Set(toFloat(call.Argument(0)))
+	date.Set(call.Argument(0).float64())
 	object.value = date
 	return date.Value()
 }
@@ -126,16 +126,14 @@ func _builtinDate_beforeSet(call FunctionCall, argumentLimit int, timeLocal bool
 	valueList := make([]int, argumentLimit)
 	for index := 0; index < argumentLimit; index++ {
 		value := call.ArgumentList[index]
-		if value.IsNaN() {
+		nm := value.number()
+		switch nm.kind {
+		case numberInteger, numberFloat:
+		default:
 			object.value = invalidDateObject
 			return nil, nil, nil, nil
 		}
-		integer := toInteger(value)
-		if !integer.valid() {
-			object.value = invalidDateObject
-			return nil, nil, nil, nil
-		}
-		valueList[index] = int(integer.int64)
+		valueList[index] = int(nm.int64)
 	}
 	baseTime := date.Time()
 	if timeLocal {
@@ -146,7 +144,7 @@ func _builtinDate_beforeSet(call FunctionCall, argumentLimit int, timeLocal bool
 }
 
 func builtinDate_parse(call FunctionCall) Value {
-	date := toString(call.Argument(0))
+	date := call.Argument(0).string()
 	return toValue_float64(dateParse(date))
 }
 
diff --git a/builtin_error.go b/builtin_error.go
index f0daa69..447c5fe 100644
--- a/builtin_error.go
+++ b/builtin_error.go
@@ -21,13 +21,13 @@ func builtinError_toString(call FunctionCall) Value {
 	name := "Error"
 	nameValue := thisObject.get("name")
 	if nameValue.IsDefined() {
-		name = toString(nameValue)
+		name = nameValue.string()
 	}
 
 	message := ""
 	messageValue := thisObject.get("message")
 	if messageValue.IsDefined() {
-		message = toString(messageValue)
+		message = messageValue.string()
 	}
 
 	if len(name) == 0 {
diff --git a/builtin_function.go b/builtin_function.go
index e9be383..2b360df 100644
--- a/builtin_function.go
+++ b/builtin_function.go
@@ -22,7 +22,7 @@ func builtinNewFunction(self *_object, argumentList []Value) Value {
 func argumentList2parameterList(argumentList []Value) []string {
 	parameterList := make([]string, 0, len(argumentList))
 	for _, value := range argumentList {
-		tmp := strings.FieldsFunc(toString(value), func(chr rune) bool {
+		tmp := strings.FieldsFunc(value.string(), func(chr rune) bool {
 			return chr == ',' || unicode.IsSpace(chr)
 		})
 		parameterList = append(parameterList, tmp...)
@@ -38,10 +38,10 @@ func builtinNewFunctionNative(runtime *_runtime, argumentList []Value) *_object
 	if count > 0 {
 		tmp := make([]string, 0, count-1)
 		for _, value := range argumentList[0 : count-1] {
-			tmp = append(tmp, toString(value))
+			tmp = append(tmp, value.string())
 		}
 		parameterList = strings.Join(tmp, ",")
-		body = toString(argumentList[count-1])
+		body = argumentList[count-1].string()
 	}
 
 	function, err := parser.ParseFunction(parameterList, body)
diff --git a/builtin_json.go b/builtin_json.go
index f7c9077..b11d812 100644
--- a/builtin_json.go
+++ b/builtin_json.go
@@ -23,7 +23,7 @@ func builtinJSON_parse(call FunctionCall) Value {
 	}
 
 	var root interface{}
-	err := json.Unmarshal([]byte(toString(call.Argument(0))), &root)
+	err := json.Unmarshal([]byte(call.Argument(0).string()), &root)
 	if err != nil {
 		panic(newSyntaxError(err.Error()))
 	}
@@ -133,7 +133,7 @@ func builtinJSON_stringify(call FunctionCall) Value {
 				default:
 					continue
 				}
-				name := toString(value)
+				name := value.string()
 				if seen[name] {
 					continue
 				}
@@ -151,21 +151,21 @@ func builtinJSON_stringify(call FunctionCall) Value {
 		if spaceValue.kind == valueObject {
 			switch spaceValue.value.(*_object).class {
 			case "String":
-				spaceValue = toValue_string(toString(spaceValue))
+				spaceValue = toValue_string(spaceValue.string())
 			case "Number":
-				spaceValue = toNumber(spaceValue)
+				spaceValue = spaceValue.numberValue()
 			}
 		}
 		switch spaceValue.kind {
 		case valueString:
-			value := toString(spaceValue)
+			value := spaceValue.string()
 			if len(value) > 10 {
 				ctx.gap = value[0:10]
 			} else {
 				ctx.gap = value
 			}
 		case valueNumber:
-			value := toInteger(spaceValue).int64
+			value := spaceValue.number().int64
 			if value > 10 {
 				value = 10
 			} else if value < 0 {
@@ -219,23 +219,23 @@ func builtinJSON_stringifyWalk(ctx _builtinJSON_stringifyContext, key string, ho
 		case "Boolean":
 			value = value._object().value.(Value)
 		case "String":
-			value = toValue_string(toString(value))
+			value = toValue_string(value.string())
 		case "Number":
-			value = toNumber(value)
+			value = value.numberValue()
 		}
 	}
 
 	switch value.kind {
 	case valueBoolean:
-		return toBoolean(value), true
+		return value.bool(), true
 	case valueString:
-		return toString(value), true
+		return value.string(), true
 	case valueNumber:
-		integer := toInteger(value)
+		integer := value.number()
 		switch integer.kind {
-		case integerValid:
+		case numberInteger:
 			return integer.int64, true
-		case integerFloat:
+		case numberFloat:
 			return integer.float64, true
 		default:
 			return nil, true
diff --git a/builtin_math.go b/builtin_math.go
index 37f7d8c..a9f4a55 100644
--- a/builtin_math.go
+++ b/builtin_math.go
@@ -8,31 +8,31 @@ import (
 // Math
 
 func builtinMath_abs(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Abs(number))
 }
 
 func builtinMath_acos(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Acos(number))
 }
 
 func builtinMath_asin(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Asin(number))
 }
 
 func builtinMath_atan(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Atan(number))
 }
 
 func builtinMath_atan2(call FunctionCall) Value {
-	y := toFloat(call.Argument(0))
+	y := call.Argument(0).float64()
 	if math.IsNaN(y) {
 		return NaNValue()
 	}
-	x := toFloat(call.Argument(1))
+	x := call.Argument(1).float64()
 	if math.IsNaN(x) {
 		return NaNValue()
 	}
@@ -40,27 +40,27 @@ func builtinMath_atan2(call FunctionCall) Value {
 }
 
 func builtinMath_cos(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Cos(number))
 }
 
 func builtinMath_ceil(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Ceil(number))
 }
 
 func builtinMath_exp(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Exp(number))
 }
 
 func builtinMath_floor(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Floor(number))
 }
 
 func builtinMath_log(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Log(number))
 }
 
@@ -69,14 +69,14 @@ func builtinMath_max(call FunctionCall) Value {
 	case 0:
 		return negativeInfinityValue()
 	case 1:
-		return toValue_float64(toFloat(call.ArgumentList[0]))
+		return toValue_float64(call.ArgumentList[0].float64())
 	}
-	result := toFloat(call.ArgumentList[0])
+	result := call.ArgumentList[0].float64()
 	if math.IsNaN(result) {
 		return NaNValue()
 	}
 	for _, value := range call.ArgumentList[1:] {
-		value := toFloat(value)
+		value := value.float64()
 		if math.IsNaN(value) {
 			return NaNValue()
 		}
@@ -90,14 +90,14 @@ func builtinMath_min(call FunctionCall) Value {
 	case 0:
 		return positiveInfinityValue()
 	case 1:
-		return toValue_float64(toFloat(call.ArgumentList[0]))
+		return toValue_float64(call.ArgumentList[0].float64())
 	}
-	result := toFloat(call.ArgumentList[0])
+	result := call.ArgumentList[0].float64()
 	if math.IsNaN(result) {
 		return NaNValue()
 	}
 	for _, value := range call.ArgumentList[1:] {
-		value := toFloat(value)
+		value := value.float64()
 		if math.IsNaN(value) {
 			return NaNValue()
 		}
@@ -108,8 +108,8 @@ func builtinMath_min(call FunctionCall) Value {
 
 func builtinMath_pow(call FunctionCall) Value {
 	// TODO Make sure this works according to the specification (15.8.2.13)
-	x := toFloat(call.Argument(0))
-	y := toFloat(call.Argument(1))
+	x := call.Argument(0).float64()
+	y := call.Argument(1).float64()
 	if math.Abs(x) == 1 && math.IsInf(y, 0) {
 		return NaNValue()
 	}
@@ -121,7 +121,7 @@ func builtinMath_random(call FunctionCall) Value {
 }
 
 func builtinMath_round(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	value := math.Floor(number + 0.5)
 	if value == 0 {
 		value = math.Copysign(0, number)
@@ -130,16 +130,16 @@ func builtinMath_round(call FunctionCall) Value {
 }
 
 func builtinMath_sin(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Sin(number))
 }
 
 func builtinMath_sqrt(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Sqrt(number))
 }
 
 func builtinMath_tan(call FunctionCall) Value {
-	number := toFloat(call.Argument(0))
+	number := call.Argument(0).float64()
 	return toValue_float64(math.Tan(number))
 }
diff --git a/builtin_number.go b/builtin_number.go
index b020dbe..3091846 100644
--- a/builtin_number.go
+++ b/builtin_number.go
@@ -9,7 +9,7 @@ import (
 
 func numberValueFromNumberArgumentList(argumentList []Value) Value {
 	if len(argumentList) > 0 {
-		return toNumber(argumentList[0])
+		return argumentList[0].numberValue()
 	}
 	return toValue_int(0)
 }
@@ -35,7 +35,7 @@ func builtinNumber_toString(call FunctionCall) Value {
 		radix = int(integer)
 	}
 	if radix == 10 {
-		return toValue_string(toString(value))
+		return toValue_string(value.string())
 	}
 	return toValue_string(numberToStringRadix(value, radix))
 }
@@ -52,11 +52,11 @@ func builtinNumber_toFixed(call FunctionCall) Value {
 	if call.This.IsNaN() {
 		return toValue_string("NaN")
 	}
-	value := toFloat(call.This)
+	value := call.This.float64()
 	if math.Abs(value) >= 1e21 {
 		return toValue_string(floatToString(value, 64))
 	}
-	return toValue_string(strconv.FormatFloat(toFloat(call.This), 'f', int(precision), 64))
+	return toValue_string(strconv.FormatFloat(call.This.float64(), 'f', int(precision), 64))
 }
 
 func builtinNumber_toExponential(call FunctionCall) Value {
@@ -70,7 +70,7 @@ func builtinNumber_toExponential(call FunctionCall) Value {
 			panic(newRangeError("RangeError: toExponential() precision must be greater than 0"))
 		}
 	}
-	return toValue_string(strconv.FormatFloat(toFloat(call.This), 'e', int(precision), 64))
+	return toValue_string(strconv.FormatFloat(call.This.float64(), 'e', int(precision), 64))
 }
 
 func builtinNumber_toPrecision(call FunctionCall) Value {
@@ -79,13 +79,13 @@ func builtinNumber_toPrecision(call FunctionCall) Value {
 	}
 	value := call.Argument(0)
 	if value.IsUndefined() {
-		return toValue_string(toString(call.This))
+		return toValue_string(call.This.string())
 	}
 	precision := toIntegerFloat(value)
 	if 1 > precision {
 		panic(newRangeError("RangeError: toPrecision() precision must be greater than 1"))
 	}
-	return toValue_string(strconv.FormatFloat(toFloat(call.This), 'g', int(precision), 64))
+	return toValue_string(strconv.FormatFloat(call.This.float64(), 'g', int(precision), 64))
 }
 
 func builtinNumber_toLocaleString(call FunctionCall) Value {
diff --git a/builtin_object.go b/builtin_object.go
index d13ba19..ee1ceb4 100644
--- a/builtin_object.go
+++ b/builtin_object.go
@@ -34,7 +34,7 @@ func builtinObject_valueOf(call FunctionCall) Value {
 }
 
 func builtinObject_hasOwnProperty(call FunctionCall) Value {
-	propertyName := toString(call.Argument(0))
+	propertyName := call.Argument(0).string()
 	thisObject := call.thisObject()
 	return toValue_bool(thisObject.hasOwnProperty(propertyName))
 }
@@ -56,7 +56,7 @@ func builtinObject_isPrototypeOf(call FunctionCall) Value {
 }
 
 func builtinObject_propertyIsEnumerable(call FunctionCall) Value {
-	propertyName := toString(call.Argument(0))
+	propertyName := call.Argument(0).string()
 	thisObject := call.thisObject()
 	property := thisObject.getOwnProperty(propertyName)
 	if property != nil && property.enumerable() {
@@ -106,7 +106,7 @@ func builtinObject_getOwnPropertyDescriptor(call FunctionCall) Value {
 		panic(newTypeError())
 	}
 
-	name := toString(call.Argument(1))
+	name := call.Argument(1).string()
 	descriptor := object.getOwnProperty(name)
 	if descriptor == nil {
 		return Value{}
@@ -120,7 +120,7 @@ func builtinObject_defineProperty(call FunctionCall) Value {
 	if object == nil {
 		panic(newTypeError())
 	}
-	name := toString(call.Argument(1))
+	name := call.Argument(1).string()
 	descriptor := toPropertyDescriptor(call.Argument(2))
 	object.defineOwnProperty(name, descriptor, true)
 	return objectValue
diff --git a/builtin_regexp.go b/builtin_regexp.go
index fe6e5fb..9942251 100644
--- a/builtin_regexp.go
+++ b/builtin_regexp.go
@@ -26,15 +26,15 @@ func builtinNewRegExp(self *_object, argumentList []Value) Value {
 
 func builtinRegExp_toString(call FunctionCall) Value {
 	thisObject := call.thisObject()
-	source := toString(thisObject.get("source"))
+	source := thisObject.get("source").string()
 	flags := []byte{}
-	if toBoolean(thisObject.get("global")) {
+	if thisObject.get("global").bool() {
 		flags = append(flags, 'g')
 	}
-	if toBoolean(thisObject.get("ignoreCase")) {
+	if thisObject.get("ignoreCase").bool() {
 		flags = append(flags, 'i')
 	}
-	if toBoolean(thisObject.get("multiline")) {
+	if thisObject.get("multiline").bool() {
 		flags = append(flags, 'm')
 	}
 	return toValue_string(fmt.Sprintf("/%s/%s", source, flags))
@@ -42,7 +42,7 @@ func builtinRegExp_toString(call FunctionCall) Value {
 
 func builtinRegExp_exec(call FunctionCall) Value {
 	thisObject := call.thisObject()
-	target := toString(call.Argument(0))
+	target := call.Argument(0).string()
 	match, result := execRegExp(thisObject, target)
 	if !match {
 		return nullValue
@@ -52,7 +52,7 @@ func builtinRegExp_exec(call FunctionCall) Value {
 
 func builtinRegExp_test(call FunctionCall) Value {
 	thisObject := call.thisObject()
-	target := toString(call.Argument(0))
+	target := call.Argument(0).string()
 	match, _ := execRegExp(thisObject, target)
 	return toValue_bool(match)
 }
diff --git a/builtin_string.go b/builtin_string.go
index 58881e0..067dde5 100644
--- a/builtin_string.go
+++ b/builtin_string.go
@@ -12,7 +12,7 @@ import (
 
 func stringValueFromStringArgumentList(argumentList []Value) Value {
 	if len(argumentList) > 0 {
-		return toValue_string(toString(argumentList[0]))
+		return toValue_string(argumentList[0].string())
 	}
 	return toValue_string("")
 }
@@ -42,7 +42,7 @@ func builtinString_fromCharCode(call FunctionCall) Value {
 
 func builtinString_charAt(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	idx := int(toInteger(call.Argument(0)).int64)
+	idx := int(call.Argument(0).number().int64)
 	chr := stringAt(call.This._object().stringValue(), idx)
 	if chr == utf8.RuneError {
 		return toValue_string("")
@@ -52,7 +52,7 @@ func builtinString_charAt(call FunctionCall) Value {
 
 func builtinString_charCodeAt(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	idx := int(toInteger(call.Argument(0)).int64)
+	idx := int(call.Argument(0).number().int64)
 	chr := stringAt(call.This._object().stringValue(), idx)
 	if chr == utf8.RuneError {
 		return NaNValue()
@@ -63,17 +63,17 @@ func builtinString_charCodeAt(call FunctionCall) Value {
 func builtinString_concat(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
 	var value bytes.Buffer
-	value.WriteString(toString(call.This))
+	value.WriteString(call.This.string())
 	for _, item := range call.ArgumentList {
-		value.WriteString(toString(item))
+		value.WriteString(item.string())
 	}
 	return toValue_string(value.String())
 }
 
 func builtinString_indexOf(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	value := toString(call.This)
-	target := toString(call.Argument(0))
+	value := call.This.string()
+	target := call.Argument(0).string()
 	if 2 > len(call.ArgumentList) {
 		return toValue_int(strings.Index(value, target))
 	}
@@ -95,8 +95,8 @@ func builtinString_indexOf(call FunctionCall) Value {
 
 func builtinString_lastIndexOf(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	value := toString(call.This)
-	target := toString(call.Argument(0))
+	value := call.This.string()
+	target := call.Argument(0).string()
 	if 2 > len(call.ArgumentList) || call.ArgumentList[1].IsUndefined() {
 		return toValue_int(strings.LastIndex(value, target))
 	}
@@ -104,8 +104,8 @@ func builtinString_lastIndexOf(call FunctionCall) Value {
 	if length == 0 {
 		return toValue_int(strings.LastIndex(value, target))
 	}
-	start := toInteger(call.ArgumentList[1])
-	if !start.valid() {
+	start := call.ArgumentList[1].number()
+	if start.kind == numberInfinity { // FIXME
 		// startNumber is infinity, so start is the end of string (start = length)
 		return toValue_int(strings.LastIndex(value, target))
 	}
@@ -121,13 +121,13 @@ func builtinString_lastIndexOf(call FunctionCall) Value {
 
 func builtinString_match(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := toString(call.This)
+	target := call.This.string()
 	matcherValue := call.Argument(0)
 	matcher := matcherValue._object()
 	if !matcherValue.IsObject() || matcher.class != "RegExp" {
 		matcher = call.runtime.newRegExp(matcherValue, Value{})
 	}
-	global := toBoolean(matcher.get("global"))
+	global := matcher.get("global").bool()
 	if !global {
 		match, result := execRegExp(matcher, target)
 		if !match {
@@ -190,7 +190,7 @@ func builtinString_findAndReplaceString(input []byte, lastIndex int, match []int
 
 func builtinString_replace(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := []byte(toString(call.This))
+	target := []byte(call.This.string())
 	searchValue := call.Argument(0)
 	searchObject := searchValue._object()
 
@@ -205,7 +205,7 @@ func builtinString_replace(call FunctionCall) Value {
 			find = -1
 		}
 	} else {
-		search = regexp.MustCompile(regexp.QuoteMeta(toString(searchValue)))
+		search = regexp.MustCompile(regexp.QuoteMeta(searchValue.string()))
 	}
 
 	found := search.FindAllSubmatchIndex(target, find)
@@ -237,13 +237,13 @@ func builtinString_replace(call FunctionCall) Value {
 				}
 				argumentList[matchCount+0] = toValue_int(match[0])
 				argumentList[matchCount+1] = toValue_string(target)
-				replacement := toString(replace.call(Value{}, argumentList, false))
+				replacement := replace.call(Value{}, argumentList, false).string()
 				result = append(result, []byte(replacement)...)
 				lastIndex = match[1]
 			}
 
 		} else {
-			replace := []byte(toString(replaceValue))
+			replace := []byte(replaceValue.string())
 			for _, match := range found {
 				result = builtinString_findAndReplaceString(result, lastIndex, match, target, replace)
 				lastIndex = match[1]
@@ -264,7 +264,7 @@ func builtinString_replace(call FunctionCall) Value {
 
 func builtinString_search(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := toString(call.This)
+	target := call.This.string()
 	searchValue := call.Argument(0)
 	search := searchValue._object()
 	if !searchValue.IsObject() || search.class != "RegExp" {
@@ -290,7 +290,7 @@ func stringSplitMatch(target string, targetLength int64, index uint, search stri
 
 func builtinString_split(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := toString(call.This)
+	target := call.This.string()
 
 	separatorValue := call.Argument(0)
 	limitValue := call.Argument(1)
@@ -365,7 +365,7 @@ func builtinString_split(call FunctionCall) Value {
 		return toValue_object(call.runtime.newArrayOf(valueArray))
 
 	} else {
-		separator := toString(separatorValue)
+		separator := separatorValue.string()
 
 		splitLimit := limit
 		excess := false
@@ -391,7 +391,7 @@ func builtinString_split(call FunctionCall) Value {
 
 func builtinString_slice(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := toString(call.This)
+	target := call.This.string()
 
 	length := int64(len(target))
 	start, end := rangeStartEnd(call.ArgumentList, length, false)
@@ -403,7 +403,7 @@ func builtinString_slice(call FunctionCall) Value {
 
 func builtinString_substring(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	target := toString(call.This)
+	target := call.This.string()
 
 	length := int64(len(target))
 	start, end := rangeStartEnd(call.ArgumentList, length, true)
@@ -414,7 +414,7 @@ func builtinString_substring(call FunctionCall) Value {
 }
 
 func builtinString_substr(call FunctionCall) Value {
-	target := toString(call.This)
+	target := call.This.string()
 
 	size := int64(len(target))
 	start, length := rangeStartLength(call.ArgumentList, size)
@@ -440,12 +440,12 @@ func builtinString_substr(call FunctionCall) Value {
 
 func builtinString_toLowerCase(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue_string(strings.ToLower(toString(call.This)))
+	return toValue_string(strings.ToLower(call.This.string()))
 }
 
 func builtinString_toUpperCase(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue_string(strings.ToUpper(toString(call.This)))
+	return toValue_string(strings.ToUpper(call.This.string()))
 }
 
 // 7.2 Table 2 — Whitespace Characters & 7.3 Table 3 - Line Terminator Characters
@@ -453,28 +453,28 @@ const builtinString_trim_whitespace = "\u0009\u000A\u000B\u000C\u000D\u0020\u00A
 
 func builtinString_trim(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue(strings.Trim(toString(call.This),
+	return toValue(strings.Trim(call.This.string(),
 		builtinString_trim_whitespace))
 }
 
 // Mozilla extension, not ECMAScript 5
 func builtinString_trimLeft(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue(strings.TrimLeft(toString(call.This),
+	return toValue(strings.TrimLeft(call.This.string(),
 		builtinString_trim_whitespace))
 }
 
 // Mozilla extension, not ECMAScript 5
 func builtinString_trimRight(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue(strings.TrimRight(toString(call.This),
+	return toValue(strings.TrimRight(call.This.string(),
 		builtinString_trim_whitespace))
 }
 
 func builtinString_localeCompare(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	this := toString(call.This)
-	that := toString(call.Argument(0))
+	this := call.This.string()
+	that := call.Argument(0).string()
 	if this < that {
 		return toValue_int(-1)
 	} else if this == that {
@@ -487,7 +487,7 @@ func builtinString_localeCompare(call FunctionCall) Value {
 An alternate version of String.trim
 func builtinString_trim(call FunctionCall) Value {
 	checkObjectCoercible(call.This)
-	return toValue_string(strings.TrimFunc(toString(call.This), isWhiteSpaceOrLineTerminator))
+	return toValue_string(strings.TrimFunc(call.string(.This), isWhiteSpaceOrLineTerminator))
 }
 */
 
diff --git a/cmpl_evaluate.go b/cmpl_evaluate.go
index 48223fd..c249a02 100644
--- a/cmpl_evaluate.go
+++ b/cmpl_evaluate.go
@@ -52,7 +52,7 @@ func (self *_runtime) cmpl_call_nodeFunction(function *_object, stash *_fnStash,
 	self.cmpl_variableDeclaration(node.varList)
 
 	result := self.cmpl_evaluate_nodeStatement(node.body)
-	if result.isResult() {
+	if result.kind == valueResult {
 		return result
 	}
 
diff --git a/cmpl_evaluate_expression.go b/cmpl_evaluate_expression.go
index ef4c686..ea82d44 100644
--- a/cmpl_evaluate_expression.go
+++ b/cmpl_evaluate_expression.go
@@ -142,13 +142,13 @@ func (self *_runtime) cmpl_evaluate_nodeBinaryExpression(node *_nodeBinaryExpres
 	switch node.operator {
 	// Logical
 	case token.LOGICAL_AND:
-		if !toBoolean(leftValue) {
+		if !leftValue.bool() {
 			return leftValue
 		}
 		right := self.cmpl_evaluate_nodeExpression(node.right)
 		return right.resolve()
 	case token.LOGICAL_OR:
-		if toBoolean(leftValue) {
+		if leftValue.bool() {
 			return leftValue
 		}
 		right := self.cmpl_evaluate_nodeExpression(node.right)
@@ -173,7 +173,7 @@ func (self *_runtime) cmpl_evaluate_nodeBracketExpression(node *_nodeBracketExpr
 	memberValue := member.resolve()
 
 	// TODO Pass in base value as-is, and defer toObject till later?
-	return toValue(newPropertyReference(self.toObject(targetValue), toString(memberValue), false))
+	return toValue(newPropertyReference(self.toObject(targetValue), memberValue.string(), false))
 }
 
 func (self *_runtime) cmpl_evaluate_nodeCallExpression(node *_nodeCallExpression, withArgumentList []interface{}) Value {
@@ -212,7 +212,7 @@ func (self *_runtime) cmpl_evaluate_nodeCallExpression(node *_nodeCallExpression
 func (self *_runtime) cmpl_evaluate_nodeConditionalExpression(node *_nodeConditionalExpression) Value {
 	test := self.cmpl_evaluate_nodeExpression(node.test)
 	testValue := test.resolve()
-	if toBoolean(testValue) {
+	if testValue.bool() {
 		return self.cmpl_evaluate_nodeExpression(node.consequent)
 	}
 	return self.cmpl_evaluate_nodeExpression(node.alternate)
@@ -295,7 +295,7 @@ func (self *_runtime) cmpl_evaluate_nodeUnaryExpression(node *_nodeUnaryExpressi
 	switch node.operator {
 	case token.NOT:
 		targetValue := target.resolve()
-		if targetValue.toBoolean() {
+		if targetValue.bool() {
 			return falseValue
 		}
 		return trueValue
@@ -305,10 +305,10 @@ func (self *_runtime) cmpl_evaluate_nodeUnaryExpression(node *_nodeUnaryExpressi
 		return toValue_int32(^integerValue)
 	case token.PLUS:
 		targetValue := target.resolve()
-		return toValue_float64(targetValue.toFloat())
+		return toValue_float64(targetValue.float64())
 	case token.MINUS:
 		targetValue := target.resolve()
-		value := targetValue.toFloat()
+		value := targetValue.float64()
 		// TODO Test this
 		sign := float64(-1)
 		if math.Signbit(value) {
@@ -319,13 +319,13 @@ func (self *_runtime) cmpl_evaluate_nodeUnaryExpression(node *_nodeUnaryExpressi
 		targetValue := target.resolve()
 		if node.postfix {
 			// Postfix++
-			oldValue := targetValue.toFloat()
+			oldValue := targetValue.float64()
 			newValue := toValue_float64(+1 + oldValue)
 			self.putValue(target.reference(), newValue)
 			return toValue_float64(oldValue)
 		} else {
 			// ++Prefix
-			newValue := toValue_float64(+1 + targetValue.toFloat())
+			newValue := toValue_float64(+1 + targetValue.float64())
 			self.putValue(target.reference(), newValue)
 			return newValue
 		}
@@ -333,13 +333,13 @@ func (self *_runtime) cmpl_evaluate_nodeUnaryExpression(node *_nodeUnaryExpressi
 		targetValue := target.resolve()
 		if node.postfix {
 			// Postfix--
-			oldValue := targetValue.toFloat()
+			oldValue := targetValue.float64()
 			newValue := toValue_float64(-1 + oldValue)
 			self.putValue(target.reference(), newValue)
 			return toValue_float64(oldValue)
 		} else {
 			// --Prefix
-			newValue := toValue_float64(-1 + targetValue.toFloat())
+			newValue := toValue_float64(-1 + targetValue.float64())
 			self.putValue(target.reference(), newValue)
 			return newValue
 		}
diff --git a/cmpl_evaluate_statement.go b/cmpl_evaluate_statement.go
index c75f8c4..c68a64c 100644
--- a/cmpl_evaluate_statement.go
+++ b/cmpl_evaluate_statement.go
@@ -150,7 +150,7 @@ resultBreak:
 			}
 		}
 	resultContinue:
-		if !self.cmpl_evaluate_nodeExpression(test).resolve().isTrue() {
+		if !self.cmpl_evaluate_nodeExpression(test).resolve().bool() {
 			// Stahp: do ... while (false)
 			break
 		}
@@ -184,7 +184,7 @@ func (self *_runtime) cmpl_evaluate_nodeForInStatement(node *_nodeForInStatement
 			into := self.cmpl_evaluate_nodeExpression(into)
 			// In the case of: for (var abc in def) ...
 			if into.reference() == nil {
-				identifier := toString(into)
+				identifier := into.string()
 				// TODO Should be true or false (strictness) depending on context
 				into = toValue(getIdentifierReference(self.scope.lexical, identifier, false))
 			}
@@ -242,7 +242,7 @@ resultBreak:
 		if test != nil {
 			testResult := self.cmpl_evaluate_nodeExpression(test)
 			testResultValue := testResult.resolve()
-			if toBoolean(testResultValue) == false {
+			if testResultValue.bool() == false {
 				break
 			}
 		}
@@ -275,7 +275,7 @@ resultBreak:
 func (self *_runtime) cmpl_evaluate_nodeIfStatement(node *_nodeIfStatement) Value {
 	test := self.cmpl_evaluate_nodeExpression(node.test)
 	testValue := test.resolve()
-	if toBoolean(testValue) {
+	if testValue.bool() {
 		return self.cmpl_evaluate_nodeStatement(node.consequent)
 	} else if node.alternate != nil {
 		return self.cmpl_evaluate_nodeStatement(node.alternate)
@@ -351,7 +351,7 @@ func (self *_runtime) cmpl_evaluate_nodeTryStatement(node *_nodeTryStatement) Va
 
 	if node.finally != nil {
 		finallyValue := self.cmpl_evaluate_nodeStatement(node.finally)
-		if finallyValue.isResult() {
+		if finallyValue.kind == valueResult {
 			return finallyValue
 		}
 	}
@@ -373,7 +373,7 @@ func (self *_runtime) cmpl_evaluate_nodeWhileStatement(node *_nodeWhileStatement
 	result := emptyValue
 resultBreakContinue:
 	for {
-		if !self.cmpl_evaluate_nodeExpression(test).resolve().isTrue() {
+		if !self.cmpl_evaluate_nodeExpression(test).resolve().bool() {
 			// Stahp: while (false) ...
 			break
 		}
diff --git a/error.go b/error.go
index 93a13fe..a953e5d 100644
--- a/error.go
+++ b/error.go
@@ -136,7 +136,7 @@ func catchPanic(function func()) (err error) {
 				}
 				return
 			case Value:
-				err = errors.New(toString(caught))
+				err = errors.New(caught.string())
 				return
 				//case string:
 				//    if strings.HasPrefix(caught, "SyntaxError:") {
diff --git a/evaluate.go b/evaluate.go
index e58d1e7..4cff1d8 100644
--- a/evaluate.go
+++ b/evaluate.go
@@ -65,38 +65,38 @@ func (self *_runtime) calculateBinaryExpression(operator token.Token, left Value
 		rightValue = toPrimitive(rightValue)
 
 		if leftValue.IsString() || rightValue.IsString() {
-			return toValue_string(strings.Join([]string{leftValue.toString(), rightValue.toString()}, ""))
+			return toValue_string(strings.Join([]string{leftValue.string(), rightValue.string()}, ""))
 		} else {
-			return toValue_float64(leftValue.toFloat() + rightValue.toFloat())
+			return toValue_float64(leftValue.float64() + rightValue.float64())
 		}
 	case token.MINUS:
 		rightValue := right.resolve()
-		return toValue_float64(leftValue.toFloat() - rightValue.toFloat())
+		return toValue_float64(leftValue.float64() - rightValue.float64())
 
 		// Multiplicative
 	case token.MULTIPLY:
 		rightValue := right.resolve()
-		return toValue_float64(leftValue.toFloat() * rightValue.toFloat())
+		return toValue_float64(leftValue.float64() * rightValue.float64())
 	case token.SLASH:
 		rightValue := right.resolve()
-		return self.evaluateDivide(leftValue.toFloat(), rightValue.toFloat())
+		return self.evaluateDivide(leftValue.float64(), rightValue.float64())
 	case token.REMAINDER:
 		rightValue := right.resolve()
-		return toValue_float64(math.Mod(leftValue.toFloat(), rightValue.toFloat()))
+		return toValue_float64(math.Mod(leftValue.float64(), rightValue.float64()))
 
 		// Logical
 	case token.LOGICAL_AND:
-		left := toBoolean(leftValue)
+		left := leftValue.bool()
 		if !left {
 			return falseValue
 		}
-		return toValue_bool(toBoolean(right.resolve()))
+		return toValue_bool(right.resolve().bool())
 	case token.LOGICAL_OR:
-		left := toBoolean(leftValue)
+		left := leftValue.bool()
 		if left {
 			return trueValue
 		}
-		return toValue_bool(toBoolean(right.resolve()))
+		return toValue_bool(right.resolve().bool())
 
 		// Bitwise
 	case token.AND:
@@ -134,7 +134,7 @@ func (self *_runtime) calculateBinaryExpression(operator token.Token, left Value
 		if !rightValue.IsObject() {
 			panic(newTypeError())
 		}
-		return toValue_bool(rightValue._object().hasProperty(toString(leftValue)))
+		return toValue_bool(rightValue._object().hasProperty(leftValue.string()))
 	}
 
 	panic(hereBeDragons(operator))
@@ -150,10 +150,10 @@ func makeEqualDispatch() map[int](func(Value, Value) bool) {
 	key := valueKindDispatchKey
 	return map[int](func(Value, Value) bool){
 
-		key(valueNumber, valueObject): func(x Value, y Value) bool { return x.toFloat() == y.toFloat() },
-		key(valueString, valueObject): func(x Value, y Value) bool { return x.toFloat() == y.toFloat() },
-		key(valueObject, valueNumber): func(x Value, y Value) bool { return x.toFloat() == y.toFloat() },
-		key(valueObject, valueString): func(x Value, y Value) bool { return x.toFloat() == y.toFloat() },
+		key(valueNumber, valueObject): func(x Value, y Value) bool { return x.float64() == y.float64() },
+		key(valueString, valueObject): func(x Value, y Value) bool { return x.float64() == y.float64() },
+		key(valueObject, valueNumber): func(x Value, y Value) bool { return x.float64() == y.float64() },
+		key(valueObject, valueString): func(x Value, y Value) bool { return x.float64() == y.float64() },
 	}
 }
 
@@ -180,13 +180,13 @@ func calculateLessThan(left Value, right Value, leftFirst bool) _lessThanResult
 
 	result := false
 	if x.kind != valueString || y.kind != valueString {
-		x, y := x.toFloat(), y.toFloat()
+		x, y := x.float64(), y.float64()
 		if math.IsNaN(x) || math.IsNaN(y) {
 			return lessThanUndefined
 		}
 		result = x < y
 	} else {
-		x, y := x.toString(), y.toString()
+		x, y := x.string(), y.string()
 		result = x < y
 	}
 
@@ -268,11 +268,11 @@ func (self *_runtime) calculateComparison(comparator token.Token, left Value, ri
 		} else if x.kind <= valueNull || y.kind <= valueNull {
 			result = false
 		} else if x.kind <= valueString && y.kind <= valueString {
-			result = x.toFloat() == y.toFloat()
+			result = x.float64() == y.float64()
 		} else if x.kind == valueBoolean {
-			result = self.calculateComparison(token.EQUAL, toValue_float64(x.toFloat()), y)
+			result = self.calculateComparison(token.EQUAL, toValue_float64(x.float64()), y)
 		} else if y.kind == valueBoolean {
-			result = self.calculateComparison(token.EQUAL, x, toValue_float64(y.toFloat()))
+			result = self.calculateComparison(token.EQUAL, x, toValue_float64(y.float64()))
 		} else if x.kind == valueObject {
 			result = self.calculateComparison(token.EQUAL, toPrimitive(x), y)
 		} else if y.kind == valueObject {
@@ -289,17 +289,17 @@ func (self *_runtime) calculateComparison(comparator token.Token, left Value, ri
 		case valueUndefined, valueNull:
 			result = true
 		case valueNumber:
-			x := x.toFloat()
-			y := y.toFloat()
+			x := x.float64()
+			y := y.float64()
 			if math.IsNaN(x) || math.IsNaN(y) {
 				result = false
 			} else {
 				result = x == y
 			}
 		case valueString:
-			result = x.toString() == y.toString()
+			result = x.string() == y.string()
 		case valueBoolean:
-			result = x.toBoolean() == y.toBoolean()
+			result = x.bool() == y.bool()
 		case valueObject:
 			result = x._object() == y._object()
 		default:
diff --git a/global.go b/global.go
index efacc3a..99a7e52 100644
--- a/global.go
+++ b/global.go
@@ -145,10 +145,10 @@ func (runtime *_runtime) newRegExp(patternValue Value, flagsValue Value) *_objec
 		flags = regExp.flags
 	} else {
 		if patternValue.IsDefined() {
-			pattern = toString(patternValue)
+			pattern = patternValue.string()
 		}
 		if flagsValue.IsDefined() {
-			flags = toString(flagsValue)
+			flags = flagsValue.string()
 		}
 	}
 
diff --git a/number_test.go b/number_test.go
index f3790e0..8db01cf 100644
--- a/number_test.go
+++ b/number_test.go
@@ -144,15 +144,13 @@ func TestNumber_toLocaleString(t *testing.T) {
 	})
 }
 
-func Test_toInteger(t *testing.T) {
+func TestValue_number(t *testing.T) {
 	tt(t, func() {
-		integer := toInteger(toValue(0.0))
-		is(integer.valid(), true)
-		is(integer.exact(), true)
+		nm := toValue(0.0).number()
+		is(nm.kind, numberInteger)
 
-		integer = toInteger(toValue(3.14159))
-		is(integer.valid(), true)
-		is(integer.exact(), false)
+		nm = toValue(3.14159).number()
+		is(nm.kind, numberFloat)
 	})
 }
 
diff --git a/object.go b/object.go
index f29a044..51d006a 100644
--- a/object.go
+++ b/object.go
@@ -98,7 +98,7 @@ func (self *_object) DefaultValue(hint _defaultValueHint) Value {
 }
 
 func (self *_object) String() string {
-	return toString(self.DefaultValue(defaultValueHintString))
+	return self.DefaultValue(defaultValueHintString).string()
 }
 
 func (self *_object) defineProperty(name string, value Value, mode _propertyMode, throw bool) bool {
diff --git a/otto_.go b/otto_.go
index b257208..e053b54 100644
--- a/otto_.go
+++ b/otto_.go
@@ -73,7 +73,7 @@ func getValueOfArrayIndex(array []Value, index int) (Value, bool) {
 // A range index can be anything from 0 up to length. It is NOT safe to use as an index
 // to an array, but is useful for slicing and in some ECMA algorithms.
 func valueToRangeIndex(indexValue Value, length int64, negativeIsZero bool) int64 {
-	index := toInteger(indexValue).int64
+	index := indexValue.number().int64
 	if negativeIsZero {
 		if index < 0 {
 			index = 0
@@ -129,7 +129,7 @@ func rangeStartLength(source []Value, size int64) (start, length int64) {
 	lengthValue := valueOfArrayIndex(source, 1)
 	if !lengthValue.IsUndefined() {
 		// Which it is not, so get the value as an array index
-		length = toInteger(lengthValue).int64
+		length = lengthValue.number().int64
 	}
 	return
 }
diff --git a/otto_test.go b/otto_test.go
index c696887..68a811d 100644
--- a/otto_test.go
+++ b/otto_test.go
@@ -649,7 +649,7 @@ func Test_PrimitiveValueObjectValue(t *testing.T) {
 		test, _ := test()
 
 		Number11 := test(`new Number(11)`)
-		is(toFloat(Number11), 11)
+		is(Number11.float64(), 11)
 	})
 }
 
@@ -866,8 +866,8 @@ func TestDotMember(t *testing.T) {
 func Test_stringToFloat(t *testing.T) {
 	tt(t, func() {
 
-		is(stringToFloat("10e10000"), _Infinity)
-		is(stringToFloat("10e10_."), _NaN)
+		is(parseNumber("10e10000"), _Infinity)
+		is(parseNumber("10e10_."), _NaN)
 	})
 }
 
diff --git a/property.go b/property.go
index ed0fccb..c07a0e0 100644
--- a/property.go
+++ b/property.go
@@ -124,7 +124,7 @@ func toPropertyDescriptor(value Value) (descriptor _property) {
 	{
 		descriptor.mode = modeSetMask // Initially nothing is set
 		if objectDescriptor.hasProperty("enumerable") {
-			if objectDescriptor.get("enumerable").toBoolean() {
+			if objectDescriptor.get("enumerable").bool() {
 				descriptor.enumerateOn()
 			} else {
 				descriptor.enumerateOff()
@@ -132,7 +132,7 @@ func toPropertyDescriptor(value Value) (descriptor _property) {
 		}
 
 		if objectDescriptor.hasProperty("configurable") {
-			if objectDescriptor.get("configurable").toBoolean() {
+			if objectDescriptor.get("configurable").bool() {
 				descriptor.configureOn()
 			} else {
 				descriptor.configureOff()
@@ -140,7 +140,7 @@ func toPropertyDescriptor(value Value) (descriptor _property) {
 		}
 
 		if objectDescriptor.hasProperty("writable") {
-			if objectDescriptor.get("writable").toBoolean() {
+			if objectDescriptor.get("writable").bool() {
 				descriptor.writeOn()
 			} else {
 				descriptor.writeOff()
diff --git a/runtime_test.go b/runtime_test.go
index 8706d59..2510a0b 100644
--- a/runtime_test.go
+++ b/runtime_test.go
@@ -359,7 +359,7 @@ func TestComparison(t *testing.T) {
 
 		test("1 == 'Hello, World.'", false)
 
-		is(stringToFloat("-1"), -1)
+		is(parseNumber("-1"), -1)
 
 		test("0+Object", "0function Object() { [native code] }")
 	})
diff --git a/type_array.go b/type_array.go
index 2443f40..598b6a4 100644
--- a/type_array.go
+++ b/type_array.go
@@ -32,11 +32,11 @@ func objectLength(object *_object) uint32 {
 }
 
 func arrayUint32(value Value) uint32 {
-	tmp := toInteger(value)
-	if !tmp.exact() || !isUint32(tmp.int64) {
+	nm := value.number()
+	if nm.kind != numberInteger || !isUint32(nm.int64) {
 		panic(newRangeError())
 	}
-	return uint32(tmp.int64)
+	return uint32(nm.int64)
 }
 
 func arrayDefineOwnProperty(self *_object, name string, descriptor _property, throw bool) bool {
diff --git a/type_boolean.go b/type_boolean.go
index c24409d..afc45c6 100644
--- a/type_boolean.go
+++ b/type_boolean.go
@@ -5,7 +5,7 @@ import (
 )
 
 func (runtime *_runtime) newBooleanObject(value Value) *_object {
-	return runtime.newPrimitiveObject("Boolean", toValue_bool(toBoolean(value)))
+	return runtime.newPrimitiveObject("Boolean", toValue_bool(value.bool()))
 }
 
 func booleanToString(value bool) string {
diff --git a/type_date.go b/type_date.go
index 65e822f..262e55e 100644
--- a/type_date.go
+++ b/type_date.go
@@ -180,7 +180,7 @@ func newDateTime(argumentList []Value, location *Time.Location) (epoch float64)
 		if index >= len(argumentList) {
 			return default_, false
 		}
-		value := toFloat(argumentList[index])
+		value := argumentList[index].float64()
 		if math.IsNaN(value) || math.IsInf(value, 0) {
 			return 0, true
 		}
@@ -226,10 +226,10 @@ func newDateTime(argumentList []Value, location *Time.Location) (epoch float64)
 		value := valueOfArrayIndex(argumentList, 0)
 		value = toPrimitive(value)
 		if value.IsString() {
-			return dateParse(toString(value))
+			return dateParse(value.string())
 		}
 
-		return toFloat(value)
+		return value.float64()
 	}
 
 INVALID:
diff --git a/type_error.go b/type_error.go
index 683fcf9..41bdaf6 100644
--- a/type_error.go
+++ b/type_error.go
@@ -3,7 +3,7 @@ package otto
 func (runtime *_runtime) newErrorObject(message Value) *_object {
 	self := runtime.newClassObject("Error")
 	if message.IsDefined() {
-		self.defineProperty("message", toValue_string(toString(message)), 0111, false)
+		self.defineProperty("message", toValue_string(message.string()), 0111, false)
 	}
 	return self
 }
diff --git a/type_number.go b/type_number.go
index ee7adc9..28de444 100644
--- a/type_number.go
+++ b/type_number.go
@@ -1,5 +1,5 @@
 package otto
 
 func (runtime *_runtime) newNumberObject(value Value) *_object {
-	return runtime.newPrimitiveObject("Number", toNumber(value))
+	return runtime.newPrimitiveObject("Number", value.numberValue())
 }
diff --git a/type_regexp.go b/type_regexp.go
index 5ad9138..e305d91 100644
--- a/type_regexp.go
+++ b/type_regexp.go
@@ -88,9 +88,9 @@ func execRegExp(this *_object, target string) (match bool, result []int) {
 	if this.class != "RegExp" {
 		panic(newTypeError("Calling RegExp.exec on a non-RegExp object"))
 	}
-	lastIndex := toInteger(this.get("lastIndex")).int64
+	lastIndex := this.get("lastIndex").number().int64
 	index := lastIndex
-	global := toBoolean(this.get("global"))
+	global := this.get("global").bool()
 	if !global {
 		index = 0
 	}
diff --git a/type_string.go b/type_string.go
index fd93316..ef3afa4 100644
--- a/type_string.go
+++ b/type_string.go
@@ -70,7 +70,7 @@ func stringAt(str _stringObject, index int) rune {
 }
 
 func (runtime *_runtime) newStringObject(value Value) *_object {
-	str := _newStringObject(toString(value))
+	str := _newStringObject(value.string())
 
 	self := runtime.newClassObject("String")
 	self.defineProperty("length", toValue_int(str.Length()), 0, false)
diff --git a/underscore_test.go b/underscore_test.go
index 2c58b1e..d8bf2da 100644
--- a/underscore_test.go
+++ b/underscore_test.go
@@ -36,10 +36,10 @@ func (self *_tester) underscore() {
 	}
 
 	vm.Set("assert", func(call FunctionCall) Value {
-		if !toBoolean(call.Argument(0)) {
+		if !call.Argument(0).bool() {
 			message := "Assertion failed"
 			if len(call.ArgumentList) > 1 {
-				message = toString(call.ArgumentList[1])
+				message = call.ArgumentList[1].string()
 			}
 			t := terst.Caller().T()
 			is(message, nil)
diff --git a/value.go b/value.go
index 7470ce2..a3a8153 100644
--- a/value.go
+++ b/value.go
@@ -94,14 +94,6 @@ func (value Value) isCallable() bool {
 	return false
 }
 
-func (value Value) isResult() bool {
-	return value.kind == valueResult
-}
-
-func (value Value) isReference() bool {
-	return value.kind == valueReference
-}
-
 // Call the value as a function with the given this value and argument list and
 // return the result of invocation. It is essentially equivalent to:
 //
@@ -176,7 +168,7 @@ func (value Value) IsNaN() bool {
 		return false
 	}
 
-	return math.IsNaN(toFloat(value))
+	return math.IsNaN(value.float64())
 }
 
 // IsString will return true if value is a string (primitive).
@@ -383,19 +375,11 @@ func toValue(value interface{}) Value {
 func (value Value) String() string {
 	result := ""
 	catchPanic(func() {
-		result = value.toString()
+		result = value.string()
 	})
 	return result
 }
 
-func (value Value) toBoolean() bool {
-	return toBoolean(value)
-}
-
-func (value Value) isTrue() bool {
-	return toBoolean(value)
-}
-
 // ToBoolean will convert the value to a boolean (bool).
 //
 //		ToValue(0).ToBoolean() => false
@@ -408,17 +392,16 @@ func (value Value) isTrue() bool {
 func (value Value) ToBoolean() (bool, error) {
 	result := false
 	err := catchPanic(func() {
-		result = toBoolean(value)
+		result = value.bool()
 	})
 	return result, err
 }
 
-func (value Value) toNumber() Value {
-	return toNumber(value)
-}
-
-func (value Value) toFloat() float64 {
-	return toFloat(value)
+func (value Value) numberValue() Value {
+	if value.kind == valueNumber {
+		return value
+	}
+	return Value{valueNumber, value.float64()}
 }
 
 // ToFloat will convert the value to a number (float64).
@@ -431,7 +414,7 @@ func (value Value) toFloat() float64 {
 func (value Value) ToFloat() (float64, error) {
 	result := float64(0)
 	err := catchPanic(func() {
-		result = toFloat(value)
+		result = value.float64()
 	})
 	return result, err
 }
@@ -446,15 +429,11 @@ func (value Value) ToFloat() (float64, error) {
 func (value Value) ToInteger() (int64, error) {
 	result := int64(0)
 	err := catchPanic(func() {
-		result = toInteger(value).int64
+		result = value.number().int64
 	})
 	return result, err
 }
 
-func (value Value) toString() string {
-	return toString(value)
-}
-
 // ToString will convert the value to a string (string).
 //
 //		ToValue(0).ToString() => "0"
@@ -467,7 +446,7 @@ func (value Value) toString() string {
 func (value Value) ToString() (string, error) {
 	result := ""
 	err := catchPanic(func() {
-		result = toString(value)
+		result = value.string()
 	})
 	return result, err
 }
@@ -586,8 +565,8 @@ func sameValue(x Value, y Value) bool {
 	case valueUndefined, valueNull:
 		result = true
 	case valueNumber:
-		x := x.toFloat()
-		y := y.toFloat()
+		x := x.float64()
+		y := y.float64()
 		if math.IsNaN(x) && math.IsNaN(y) {
 			result = true
 		} else {
@@ -598,9 +577,9 @@ func sameValue(x Value, y Value) bool {
 			}
 		}
 	case valueString:
-		result = x.toString() == y.toString()
+		result = x.string() == y.string()
 	case valueBoolean:
-		result = x.toBoolean() == y.toBoolean()
+		result = x.bool() == y.bool()
 	case valueObject:
 		result = x._object() == y._object()
 	default:
@@ -619,17 +598,17 @@ func strictEqualityComparison(x Value, y Value) bool {
 	case valueUndefined, valueNull:
 		result = true
 	case valueNumber:
-		x := x.toFloat()
-		y := y.toFloat()
+		x := x.float64()
+		y := y.float64()
 		if math.IsNaN(x) && math.IsNaN(y) {
 			result = false
 		} else {
 			result = x == y
 		}
 	case valueString:
-		result = x.toString() == y.toString()
+		result = x.string() == y.string()
 	case valueBoolean:
-		result = x.toBoolean() == y.toBoolean()
+		result = x.bool() == y.bool()
 	case valueObject:
 		result = x._object() == y._object()
 	default:
@@ -784,7 +763,7 @@ func (self Value) exportNative() interface{} {
 func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
 	switch kind {
 	case reflect.Bool: // Bool
-		return reflect.ValueOf(value.toBoolean()), nil
+		return reflect.ValueOf(value.bool()), nil
 	case reflect.Int: // Int
 		// We convert to float64 here because converting to int64 will not tell us
 		// if a value is outside the range of int64
@@ -795,21 +774,21 @@ func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
 			return reflect.ValueOf(int(tmp)), nil
 		}
 	case reflect.Int8: // Int8
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < int64_minInt8 || tmp > int64_maxInt8 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int8", tmp, value)
 		} else {
 			return reflect.ValueOf(int8(tmp)), nil
 		}
 	case reflect.Int16: // Int16
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < int64_minInt16 || tmp > int64_maxInt16 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int16", tmp, value)
 		} else {
 			return reflect.ValueOf(int16(tmp)), nil
 		}
 	case reflect.Int32: // Int32
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < int64_minInt32 || tmp > int64_maxInt32 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to int32", tmp, value)
 		} else {
@@ -834,21 +813,21 @@ func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
 			return reflect.ValueOf(uint(tmp)), nil
 		}
 	case reflect.Uint8: // Uint8
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < 0 || tmp > int64_maxUint8 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint8", tmp, value)
 		} else {
 			return reflect.ValueOf(uint8(tmp)), nil
 		}
 	case reflect.Uint16: // Uint16
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < 0 || tmp > int64_maxUint16 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint16", tmp, value)
 		} else {
 			return reflect.ValueOf(uint16(tmp)), nil
 		}
 	case reflect.Uint32: // Uint32
-		tmp := toInteger(value).int64
+		tmp := value.number().int64
 		if tmp < 0 || tmp > int64_maxUint32 {
 			return reflect.Value{}, fmt.Errorf("RangeError: %d (%v) to uint32", tmp, value)
 		} else {
@@ -864,7 +843,7 @@ func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
 			return reflect.ValueOf(uint64(tmp)), nil
 		}
 	case reflect.Float32: // Float32
-		tmp := toFloat(value)
+		tmp := value.float64()
 		tmp1 := tmp
 		if 0 > tmp1 {
 			tmp1 = -tmp1
@@ -875,10 +854,10 @@ func (value Value) toReflectValue(kind reflect.Kind) (reflect.Value, error) {
 			return reflect.ValueOf(float32(tmp)), nil
 		}
 	case reflect.Float64: // Float64
-		value := toFloat(value)
+		value := value.float64()
 		return reflect.ValueOf(float64(value)), nil
 	case reflect.String: // String
-		return reflect.ValueOf(value.toString()), nil
+		return reflect.ValueOf(value.string()), nil
 	case reflect.Invalid: // Invalid
 	case reflect.Complex64: // FIXME? Complex64
 	case reflect.Complex128: // FIXME? Complex128
diff --git a/value_boolean.go b/value_boolean.go
index 038828e..3040f41 100644
--- a/value_boolean.go
+++ b/value_boolean.go
@@ -6,7 +6,7 @@ import (
 	"reflect"
 )
 
-func toBoolean(value Value) bool {
+func (value Value) bool() bool {
 	if value.kind == valueBoolean {
 		return value.value.(bool)
 	}
@@ -38,12 +38,3 @@ func toBoolean(value Value) bool {
 	}
 	panic(fmt.Errorf("toBoolean(%T)", value.value))
 }
-
-func stringToBoolean(value string) bool {
-	if value == "true" {
-		return true
-	} else if value == "false" {
-		return false
-	}
-	panic(fmt.Errorf("stringToBoolean(%s)", value))
-}
diff --git a/value_number.go b/value_number.go
index e41c3e3..54996c7 100644
--- a/value_number.go
+++ b/value_number.go
@@ -10,7 +10,7 @@ import (
 
 var stringToNumberParseInteger = regexp.MustCompile(`^(?:0[xX])`)
 
-func stringToFloat(value string) float64 {
+func parseNumber(value string) float64 {
 	value = strings.TrimSpace(value)
 
 	if value == "" {
@@ -41,14 +41,7 @@ func stringToFloat(value string) float64 {
 	return float64(number)
 }
 
-func toNumber(value Value) Value {
-	if value.kind == valueNumber {
-		return value
-	}
-	return Value{valueNumber, toFloat(value)}
-}
-
-func toFloat(value Value) float64 {
+func (value Value) float64() float64 {
 	switch value.kind {
 	case valueUndefined:
 		return math.NaN()
@@ -84,9 +77,9 @@ func toFloat(value Value) float64 {
 	case float64:
 		return value
 	case string:
-		return stringToFloat(value)
+		return parseNumber(value)
 	case *_object:
-		return toFloat(value.DefaultValue(defaultValueHintNumber))
+		return value.DefaultValue(defaultValueHintNumber).float64()
 	}
 	panic(fmt.Errorf("toFloat(%T)", value.value))
 }
@@ -145,7 +138,7 @@ const (
 )
 
 func toIntegerFloat(value Value) float64 {
-	float := value.toFloat()
+	float := value.float64()
 	if math.IsInf(float, 0) {
 	} else if math.IsNaN(float) {
 		float = 0
@@ -157,99 +150,88 @@ func toIntegerFloat(value Value) float64 {
 	return float
 }
 
-type _integerKind int
+type _numberKind int
 
 const (
-	integerValid    _integerKind = iota // 3.0 => 3.0
-	integerFloat                        // 3.14159 => 3.0, 1+2**63 > 2**63-1
-	integerInfinite                     // Infinity => 2**63-1
-	integerInvalid                      // NaN => 0
+	numberInteger  _numberKind = iota // 3.0 => 3.0
+	numberFloat                       // 3.14159 => 3.0, 1+2**63 > 2**63-1
+	numberInfinity                    // Infinity => 2**63-1
+	numberNaN                         // NaN => 0
 )
 
-type _integer struct {
-	kind    _integerKind
+type _number struct {
+	kind    _numberKind
 	int64   int64
 	float64 float64
 }
 
-func (self _integer) valid() bool {
-	return self.kind == integerValid || self.kind == integerFloat
-}
-
-func (self _integer) exact() bool {
-	return self.kind == integerValid
-}
-
-func (self _integer) infinite() bool {
-	return self.kind == integerInfinite
-}
-
-// Could this use some improvement?
+// FIXME
 // http://www.goinggo.net/2013/08/gustavos-ieee-754-brain-teaser.html
 // http://bazaar.launchpad.net/~niemeyer/strepr/trunk/view/6/strepr.go#L160
-func toInteger(value Value) (integer _integer) {
-	switch value := value.value.(type) {
+func (vl Value) number() (number _number) {
+	switch vl := vl.value.(type) {
 	case int8:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case int16:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case uint8:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case uint16:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case uint32:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case int:
-		integer.int64 = int64(value)
+		number.int64 = int64(vl)
 		return
 	case int64:
-		integer.int64 = value
+		number.int64 = vl
 		return
 	}
-	{
-		value := toFloat(value)
-		integer.float64 = value
-		if value == 0 {
-			return
-		}
-		if math.IsNaN(value) {
-			integer.kind = integerInvalid
-			return
-		}
-		if math.IsInf(value, 0) {
-			integer.kind = integerInfinite
-		}
-		if value >= float_maxInt64 {
-			integer.int64 = math.MaxInt64
-			integer.kind = integerFloat
-			return
-		}
-		if value <= float_minInt64 {
-			integer.int64 = math.MinInt64
-			integer.kind = integerFloat
-			return
-		}
-		{
-			value0 := value
-			value1 := float64(0)
-			if value0 > 0 {
-				value1 = math.Floor(value0)
-			} else {
-				value1 = math.Ceil(value0)
-			}
 
-			if value0 != value1 {
-				integer.kind = integerFloat
-			}
-			integer.int64 = int64(value1)
-			return
-		}
+	float := vl.float64()
+	if float == 0 {
+		return
 	}
+
+	number.kind = numberFloat
+	number.float64 = float
+
+	if math.IsNaN(float) {
+		number.kind = numberNaN
+		return
+	}
+
+	if math.IsInf(float, 0) {
+		number.kind = numberInfinity
+	}
+
+	if float >= float_maxInt64 {
+		number.int64 = math.MaxInt64
+		return
+	}
+
+	if float <= float_minInt64 {
+		number.int64 = math.MinInt64
+		return
+	}
+
+	integer := float64(0)
+	if float > 0 {
+		integer = math.Floor(float)
+	} else {
+		integer = math.Ceil(float)
+	}
+
+	if float == integer {
+		number.kind = numberInteger
+	}
+	number.int64 = int64(float)
+	return
 }
 
 // ECMA 262: 9.5
@@ -264,7 +246,7 @@ func toInt32(value Value) int32 {
 			return value
 		}
 	}
-	floatValue := value.toFloat()
+	floatValue := value.float64()
 	if math.IsNaN(floatValue) || math.IsInf(floatValue, 0) {
 		return 0
 	}
@@ -298,7 +280,7 @@ func toUint32(value Value) uint32 {
 			return value
 		}
 	}
-	floatValue := value.toFloat()
+	floatValue := value.float64()
 	if math.IsNaN(floatValue) || math.IsInf(floatValue, 0) {
 		return 0
 	}
@@ -325,7 +307,7 @@ func toUint16(value Value) uint16 {
 			return value
 		}
 	}
-	floatValue := value.toFloat()
+	floatValue := value.float64()
 	if math.IsNaN(floatValue) || math.IsInf(floatValue, 0) {
 		return 0
 	}
diff --git a/value_string.go b/value_string.go
index 71e209f..0fbfd6b 100644
--- a/value_string.go
+++ b/value_string.go
@@ -10,6 +10,8 @@ import (
 
 var matchLeading0Exponent = regexp.MustCompile(`([eE][\+\-])0+([1-9])`) // 1e-07 => 1e-7
 
+// FIXME
+// https://code.google.com/p/v8/source/browse/branches/bleeding_edge/src/conversions.cc?spec=svn18082&r=18082
 func floatToString(value float64, bitsize int) string {
 	// TODO Fit to ECMA-262 9.8.1 specification
 	if math.IsNaN(value) {
@@ -28,7 +30,7 @@ func floatToString(value float64, bitsize int) string {
 }
 
 func numberToStringRadix(value Value, radix int) string {
-	float := toFloat(value)
+	float := value.float64()
 	if math.IsNaN(float) {
 		return "NaN"
 	} else if math.IsInf(float, 1) {
@@ -42,7 +44,7 @@ func numberToStringRadix(value Value, radix int) string {
 	return strconv.FormatInt(int64(float), radix)
 }
 
-func toString(value Value) string {
+func (value Value) string() string {
 	if value.kind == valueString {
 		switch value := value.value.(type) {
 		case string:
@@ -95,7 +97,7 @@ func toString(value Value) string {
 	case string:
 		return value
 	case *_object:
-		return toString(value.DefaultValue(defaultValueHintString))
+		return value.DefaultValue(defaultValueHintString).string()
 	}
-	panic(fmt.Errorf("toString(%v %T)", value.value, value.value))
+	panic(fmt.Errorf("%v.string( %T)", value.value, value.value))
 }
diff --git a/value_test.go b/value_test.go
index 1d038bc..4a9bd54 100644
--- a/value_test.go
+++ b/value_test.go
@@ -15,7 +15,7 @@ func TestValue(t *testing.T) {
 
 		is(toValue(false), false)
 		is(toValue(1), 1)
-		is(toValue(1).toFloat(), float64(1))
+		is(toValue(1).float64(), float64(1))
 	})
 }
 
@@ -87,7 +87,7 @@ func TestToValue(t *testing.T) {
 func TestToBoolean(t *testing.T) {
 	tt(t, func() {
 		is := func(left interface{}, right bool) {
-			is(toValue(left).toBoolean(), right)
+			is(toValue(left).bool(), right)
 		}
 
 		is("", false)
@@ -104,7 +104,7 @@ func TestToFloat(t *testing.T) {
 	tt(t, func() {
 		{
 			is := func(left interface{}, right float64) {
-				is(toValue(left).toFloat(), right)
+				is(toValue(left).float64(), right)
 			}
 			is("", 0)
 			is("xyzzy", math.NaN())
@@ -114,16 +114,16 @@ func TestToFloat(t *testing.T) {
 			is(NullValue(), 0)
 			//is(newObjectValue(), math.NaN())
 		}
-		is(math.IsNaN(UndefinedValue().toFloat()), true)
+		is(math.IsNaN(UndefinedValue().float64()), true)
 	})
 }
 
 func TestToString(t *testing.T) {
 	tt(t, func() {
-		is("undefined", UndefinedValue().toString())
-		is("null", NullValue().toString())
-		is("true", toValue(true).toString())
-		is("false", toValue(false).toString())
+		is("undefined", UndefinedValue().string())
+		is("null", NullValue().string())
+		is("true", toValue(true).string())
+		is("false", toValue(false).string())
 
 		is(UndefinedValue(), "undefined")
 		is(NullValue(), "null")