reflect: add an example for Kind

Fixes #27990

Change-Id: I0f09fc6f68cec770b1c26eed2315afbf6bf6cd4d
GitHub-Last-Rev: 8486e6d501
GitHub-Pull-Request: golang/go#27991
Reviewed-on: https://go-review.googlesource.com/c/139417
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/reflect/example_test.go

@@ -13,6 +13,24 @@ import (
 	"reflect"
 )
 
+func ExampleKind() {
+	for _, v := range []interface{}{"hi", 42, func() {}} {
+		switch v := reflect.ValueOf(v); v.Kind() {
+		case reflect.String:
+			fmt.Println(v.String())
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			fmt.Println(v.Int())
+		default:
+			fmt.Printf("unhandled kind %s", v.Kind())
+		}
+	}
+
+	// Output:
+	// hi
+	// 42
+	// unhandled kind func
+}
+
 func ExampleMakeFunc() {
 	// swap is the implementation passed to MakeFunc.
 	// It must work in terms of reflect.Values so that it is possible