expressions working

Signed-off-by: Casey Lee <cplee@nektos.com>

vendor/github.com/robertkrimen/otto/value_primitive.go

@@ -0,0 +1,23 @@
+package otto
+
+func toStringPrimitive(value Value) Value {
+	return _toPrimitive(value, defaultValueHintString)
+}
+
+func toNumberPrimitive(value Value) Value {
+	return _toPrimitive(value, defaultValueHintNumber)
+}
+
+func toPrimitive(value Value) Value {
+	return _toPrimitive(value, defaultValueNoHint)
+}
+
+func _toPrimitive(value Value, hint _defaultValueHint) Value {
+	switch value.kind {
+	case valueNull, valueUndefined, valueNumber, valueString, valueBoolean:
+		return value
+	case valueObject:
+		return value._object().DefaultValue(hint)
+	}
+	panic(hereBeDragons(value.kind, value))
+}