reflect: implement PtrTo

Author: aykevl

src/reflect/type.go

@@ -133,6 +133,14 @@ func TypeOf(i interface{}) Type {
 	return ValueOf(i).typecode
 }
 
+func PtrTo(t Type) Type {
+	ptrType := t<<5 | 5 // 0b0101 == 5
+	if ptrType>>5 != t {
+		panic("reflect: PtrTo type does not fit")
+	}
+	return ptrType
+}
+
 func (t Type) String() string {
 	return "T"
 }

testdata/reflect.go

@@ -265,6 +265,13 @@ func main() {
 		println("type assertion failed (but should succeed)")
 	}
 
+	if reflect.TypeOf(new(myint)) != reflect.PtrTo(reflect.TypeOf(myint(0))) {
+		println("PtrTo failed for type myint")
+	}
+	if reflect.TypeOf(new(myslice)) != reflect.PtrTo(reflect.TypeOf(make(myslice, 0))) {
+		println("PtrTo failed for type myslice")
+	}
+
 	println("\nstruct tags")
 	TestStructTag()
 }