Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

implement IsNil() bool for those types that can be nil. most of them, anyway.

Browse source 
R=rsc
DELTA=97  (96 added, 0 deleted, 1 changed)
OCL=28596
CL=28702
This commit is contained in:
Rob Pike 2009-05-12 14:57:44 -07:00
parent c6da3e5a69
commit a8f6e38bce
2 changed files with 97 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

62
src/lib/reflect/all_test.go
View file

@ -507,3 +507,65 @@ func TestAlignment(t *testing.T) {
x1 := T2{T2inner{2, 3}, 17};
check2ndField(x1, uintptr(unsafe.Pointer(&x1.f)) - uintptr(unsafe.Pointer(&x1)), t);
}
type Nillable interface {
IsNil() bool
}
func Nil(a interface{}, t *testing.T) {
n := NewValue(a).(Nillable);
if !n.IsNil() {
t.Errorf("%v should be nil", a)
}
}
func NotNil(a interface{}, t *testing.T) {
n := NewValue(a).(Nillable);
if n.IsNil() {
t.Errorf("value of type %v should not be nil", NewValue(a).Type().String())
}
}
func TestIsNil(t *testing.T) {
// These do not implement IsNil
doNotNil := []string{"int", "float32", "struct { a int }"};
// These do implement IsNil
doNil := []string{"*int", "interface{}", "map[string]int", "func() bool", "chan int", "[]string"};
for i, ts := range doNotNil {
ty := reflect.ParseTypeString("", ts);
v := reflect.NewInitValue(ty);
if nilable, ok := v.(Nillable); ok {
t.Errorf("%s is nilable; should not be", ts)
}
}
for i, ts := range doNil {
ty := reflect.ParseTypeString("", ts);
v := reflect.NewInitValue(ty);
if nilable, ok := v.(Nillable); !ok {
t.Errorf("%s is not nilable; should be", ts)
}
}
// Check the implementations
var pi *int;
Nil(pi, t);
pi = new(int);
NotNil(pi, t);
var si []int;
Nil(si, t);
si = make([]int, 10);
NotNil(si, t);
// TODO: map and chan don't work yet
var ii interface {};
Nil(ii, t);
ii = pi;
NotNil(ii, t);
var fi func(t *testing.T);
Nil(fi, t);
fi = TestIsNil;
NotNil(fi, t);
}