88 lines
3.3 KiB
Go
88 lines
3.3 KiB
Go
// +build ignore
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package main
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import "reflect"
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import "unsafe"
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var a, b int
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var unknown bool
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func reflectIndirect() {
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ptr := &a
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// Pointer:
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print(reflect.Indirect(reflect.ValueOf(&ptr)).Interface().(*int)) // @pointsto main.a
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// Non-pointer:
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print(reflect.Indirect(reflect.ValueOf([]*int{ptr})).Interface().([]*int)[0]) // @pointsto main.a
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}
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func reflectNewAt() {
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var x [8]byte
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print(reflect.NewAt(reflect.TypeOf(3), unsafe.Pointer(&x)).Interface()) // @types *int
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}
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// @warning "unsound: main.reflectNewAt contains a reflect.NewAt.. call"
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func reflectTypeOf() {
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t := reflect.TypeOf(3)
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if unknown {
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t = reflect.TypeOf("foo")
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}
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// TODO(adonovan): make types.Eval let us refer to unexported types.
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print(t) // #@types *reflect.rtype
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print(reflect.Zero(t).Interface()) // @types int | string
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newint := reflect.New(t).Interface() // @line rtonew
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print(newint) // @types *int | *string
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print(newint.(*int)) // @pointsto <alloc in reflect.New>
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print(newint.(*string)) // @pointsto <alloc in reflect.New>
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}
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func reflectTypeElem() {
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print(reflect.Zero(reflect.TypeOf(&a).Elem()).Interface()) // @types int
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print(reflect.Zero(reflect.TypeOf([]string{}).Elem()).Interface()) // @types string
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print(reflect.Zero(reflect.TypeOf(make(chan bool)).Elem()).Interface()) // @types bool
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print(reflect.Zero(reflect.TypeOf(make(map[string]float64)).Elem()).Interface()) // @types float64
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print(reflect.Zero(reflect.TypeOf([3]complex64{}).Elem()).Interface()) // @types complex64
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print(reflect.Zero(reflect.TypeOf(3).Elem()).Interface()) // @types
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print(reflect.Zero(reflect.TypeOf(new(interface{})).Elem())) // @types interface{}
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print(reflect.Zero(reflect.TypeOf(new(interface{})).Elem()).Interface()) // @types
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}
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// reflect.Values within reflect.Values.
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func metareflection() {
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// "box" a *int twice, unbox it twice.
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v0 := reflect.ValueOf(&a)
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print(v0) // @types *int
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v1 := reflect.ValueOf(v0) // box
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print(v1) // @types reflect.Value
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v2 := reflect.ValueOf(v1) // box
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print(v2) // @types reflect.Value
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v1a := v2.Interface().(reflect.Value) // unbox
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print(v1a) // @types reflect.Value
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v0a := v1a.Interface().(reflect.Value) // unbox
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print(v0a) // @types *int
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print(v0a.Interface().(*int)) // @pointsto main.a
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// "box" an interface{} lvalue twice, unbox it twice.
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var iface interface{} = 3
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x0 := reflect.ValueOf(&iface).Elem()
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print(x0) // @types interface{}
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x1 := reflect.ValueOf(x0) // box
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print(x1) // @types reflect.Value
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x2 := reflect.ValueOf(x1) // box
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print(x2) // @types reflect.Value
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x1a := x2.Interface().(reflect.Value) // unbox
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print(x1a) // @types reflect.Value
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x0a := x1a.Interface().(reflect.Value) // unbox
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print(x0a) // @types interface{}
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print(x0a.Interface()) // @types int
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}
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func main() {
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reflectIndirect()
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reflectNewAt()
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reflectTypeOf()
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reflectTypeElem()
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metareflection()
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}
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