package main import ( "fmt" "reflect" ) func main() { var x float64 = 3.4 fmt.Println("type:", reflect.TypeOf(x)) // STOP OMIT // TODO(proppy): test output OMIT } // STOP main OMIT func f1() { // START f1 OMIT var x float64 = 3.4 v := reflect.ValueOf(x) fmt.Println("type:", v.Type()) fmt.Println("kind is float64:", v.Kind() == reflect.Float64) fmt.Println("value:", v.Float()) // STOP OMIT } func f2() { // START f2 OMIT var x uint8 = 'x' v := reflect.ValueOf(x) fmt.Println("type:", v.Type()) // uint8. fmt.Println("kind is uint8: ", v.Kind() == reflect.Uint8) // true. x = uint8(v.Uint()) // v.Uint returns a uint64. // STOP OMIT } func f3() { // START f3 OMIT type MyInt int var x MyInt = 7 v := reflect.ValueOf(x) // START f3b OMIT y := v.Interface().(float64) // y will have type float64. fmt.Println(y) // START f3c OMIT fmt.Println(v.Interface()) // START f3d OMIT fmt.Printf("value is %7.1e\n", v.Interface()) // STOP OMIT } func f4() { // START f4 OMIT var x float64 = 3.4 v := reflect.ValueOf(x) v.SetFloat(7.1) // Error: will panic. // STOP OMIT } func f5() { // START f5 OMIT var x float64 = 3.4 v := reflect.ValueOf(x) fmt.Println("settability of v:", v.CanSet()) // STOP OMIT } func f6() { // START f6 OMIT var x float64 = 3.4 v := reflect.ValueOf(x) // START f6b OMIT v.SetFloat(7.1) // STOP OMIT } func f7() { // START f7 OMIT var x float64 = 3.4 p := reflect.ValueOf(&x) // Note: take the address of x. fmt.Println("type of p:", p.Type()) fmt.Println("settability of p:", p.CanSet()) // START f7b OMIT v := p.Elem() fmt.Println("settability of v:", v.CanSet()) // START f7c OMIT v.SetFloat(7.1) fmt.Println(v.Interface()) fmt.Println(x) // STOP OMIT } func f8() { // START f8 OMIT type T struct { A int B string } t := T{23, "skidoo"} s := reflect.ValueOf(&t).Elem() typeOfT := s.Type() for i := 0; i < s.NumField(); i++ { f := s.Field(i) fmt.Printf("%d: %s %s = %v\n", i, typeOfT.Field(i).Name, f.Type(), f.Interface()) } // START f8b OMIT s.Field(0).SetInt(77) s.Field(1).SetString("Sunset Strip") fmt.Println("t is now", t) // STOP OMIT }