new tasks

Task/Delegates/Go/delegates.go

@@ -0,0 +1,39 @@
+package main
+import "fmt"
+
+type Delegator struct {
+    delegate interface{} // the delegate may be any type
+}
+
+// interface that represents anything that supports thing()
+type Thingable interface {
+    thing() string
+}
+
+func (self Delegator) operation() string {
+    if v, ok := self.delegate.(Thingable); ok {
+        return v.thing()
+    }
+    return "default implementation"
+}
+
+type Delegate int // any dummy type
+
+func (Delegate) thing() string {
+    return "delegate implementation"
+}
+
+func main() {
+    // Without a delegate:
+    a := Delegator{}
+    fmt.Println(a.operation()) // prints "default implementation"
+
+    // With a delegate that does not implement "thing"
+    a.delegate = "A delegate may be any object"
+    fmt.Println(a.operation()) // prints "default implementation"
+
+    // With a delegate:
+    var d Delegate
+    a.delegate = d
+    fmt.Println(a.operation()) // prints "delegate implementation"
+}