Added new list type which can embed any slice type

ethutil/list.go

+package ethutil
+
+import "reflect"
+
+// The list type is an anonymous slice handler which can be used
+// for containing any slice type to use in an environment which
+// does not support slice types (e.g., JavaScript, QML)
+type List struct {
+	list   reflect.Value
+	Length int
+}
+
+// Initialise a new list. Panics if non-slice type is given.
+func NewList(t interface{}) *List {
+	list := reflect.ValueOf(t)
+	if list.Kind() != reflect.Slice {
+		panic("list container initialized with a non-slice type")
+	}
+
+	return &List{list, list.Len()}
+}
+
+// Get N element from the embedded slice. Returns nil if OOB.
+func (self *List) Get(i int) interface{} {
+	if self.list.Len() > i {
+		return self.list.Index(i).Interface()
+	}
+
+	return nil
+}
+
+// Appends value at the end of the slice. Panics when incompatible value
+// is given.
+func (self *List) Append(v interface{}) {
+	self.list = reflect.Append(self.list, reflect.ValueOf(v))
+	self.Length = self.list.Len()
+}
+
+// Returns the underlying slice as interface.
+func (self *List) Interface() interface{} {
+	return self.list.Interface()
+}