initial commit

struct-embedding/structembed.go

@@ -0,0 +1,54 @@
+package main
+
+import "fmt"
+
+
+//Go struct embedding allows for structs to be embedded into interfaces
+// to express a more seamless composition of types.
+type base struct {
+	num int
+}
+
+func (b base) describe() string{
+	return fmt.Sprintf("base with num=%v",b.num)
+}
+
+//a container embeds a base
+//an embedding looks like a field without a name
+type container struct {
+	base
+	str string
+}
+
+
+func main(){
+
+		//when creating structs with literals, we have to
+		//initalize the embedding explicitly;
+		// here the embedded types serve as the field name
+		co := container{
+		base: base {
+			num: 1,
+		},
+		str: "some name",
+	}
+
+	//we can access the base's fields directly on co, e.g. co.num
+	fmt.Printf("co={num: %v str: %v}\n", co.num, co.str)
+
+	//alternativly we can spell out the full path using the embedded type name
+	fmt.Println("also num:", co.base.num)
+	//since container embeds base, the methods of base also become the methods of container
+	//here we invoke a method that was embedded from base directly on co
+	fmt.Println("describe:", co.describe())
+
+	//Embedding structs with methods may be used
+	// to bestow interface implementations onto other structs.
+	// here we see that container now implements the describer interface because it
+	// embeds base
+	type describer interface {
+		describe() string
+	}
+	var d describer = co
+	fmt.Println("describer:", d.describe())
+}