util/set: add Of variant of SetOf that takes variadic parameter

set.Of(1, 2, 3) is prettier than set.SetOf([]int{1, 2, 3}).

I was going to change the signature of SetOf but then I noticed its
name has stutter anyway, so I kept it for compatibility. People can
prefer to use set.Of for new code or slowly migrate.

Also add a lazy Make method, which I often find myself wanting,
without having to resort to uglier mak.Set(&set, k, struct{}{}).

Updates #cleanup

Change-Id: Ic6f3870115334efcbd65e79c437de2ad3edb7625
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/12019/head
Brad Fitzpatrick 6 months ago committed by Brad Fitzpatrick
parent 80decd83c1
commit 1a963342c7

@ -14,6 +14,11 @@ type Set[T comparable] map[T]struct{}
// SetOf returns a new set constructed from the elements in slice.
func SetOf[T comparable](slice []T) Set[T] {
return Of(slice...)
}
// Of returns a new set constructed from the elements in slice.
func Of[T comparable](slice ...T) Set[T] {
s := make(Set[T])
s.AddSlice(slice)
return s
@ -41,6 +46,13 @@ func (s Set[T]) AddSet(es Set[T]) {
}
}
// Make lazily initializes the map pointed to by s to be non-nil.
func (s *Set[T]) Make() {
if *s == nil {
*s = make(Set[T])
}
}
// Slice returns the elements of the set as a slice. The elements will not be
// in any particular order.
func (s Set[T]) Slice() []T {

@ -53,7 +53,7 @@ func TestSet(t *testing.T) {
}
func TestSetOf(t *testing.T) {
s := SetOf[int]([]int{1, 2, 3, 4, 4, 1})
s := Of(1, 2, 3, 4, 4, 1)
if s.Len() != 4 {
t.Errorf("wrong len %d; want 4", s.Len())
}
@ -74,20 +74,20 @@ func TestEqual(t *testing.T) {
tests := []test{
{
"equal",
SetOf([]int{1, 2, 3, 4}),
SetOf([]int{1, 2, 3, 4}),
Of(1, 2, 3, 4),
Of(1, 2, 3, 4),
true,
},
{
"not equal",
SetOf([]int{1, 2, 3, 4}),
SetOf([]int{1, 2, 3, 5}),
Of(1, 2, 3, 4),
Of(1, 2, 3, 5),
false,
},
{
"different lengths",
SetOf([]int{1, 2, 3, 4, 5}),
SetOf([]int{1, 2, 3, 5}),
Of(1, 2, 3, 4, 5),
Of(1, 2, 3, 5),
false,
},
}
@ -100,7 +100,7 @@ func TestEqual(t *testing.T) {
}
func TestClone(t *testing.T) {
s := SetOf[int]([]int{1, 2, 3, 4, 4, 1})
s := Of(1, 2, 3, 4, 4, 1)
if s.Len() != 4 {
t.Errorf("wrong len %d; want 4", s.Len())
}
@ -122,8 +122,8 @@ func TestSetJSONRoundTrip(t *testing.T) {
}{
{"empty", make(Set[string]), make(Set[int])},
{"nil", nil, nil},
{"one-item", SetOf([]string{"one"}), SetOf([]int{1})},
{"multiple-items", SetOf([]string{"one", "two", "three"}), SetOf([]int{1, 2, 3})},
{"one-item", Of("one"), Of(1)},
{"multiple-items", Of("one", "two", "three"), Of(1, 2, 3)},
}
for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
@ -158,3 +158,12 @@ func TestSetJSONRoundTrip(t *testing.T) {
})
}
}
func TestMake(t *testing.T) {
var s Set[int]
s.Make()
s.Add(1)
if !s.Contains(1) {
t.Error("missing 1")
}
}

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