feat!: support negative indices

example_test.go

@@ -149,6 +149,15 @@ func ExampleSlice_Delete() {
 	// [two five]
 }
 
+func ExampleSlice_Delete_last() {
+	s := slice.FromRaw([]int{1, 2, 3, 4, 5})
+	s.Delete(-1 /* index */, 1 /* length */)
+
+	fmt.Println(s)
+
+	// Output: [1 2 3 4]
+}
+
 func ExampleSlice_Insert() {
 	s := slice.FromRaw([]string{"one", "four"})
 	s.Insert(1, "two", "three")
@@ -167,6 +176,15 @@ func ExampleSlice_Replace() {
 	// [one two three four five]
 }
 
+func ExampleSlice_Replace_last() {
+	s := slice.FromRaw([]int{1, 2, 3, 4, 4})
+	s.Replace(-1, 5)
+	fmt.Println(s)
+
+	// Output:
+	// [1 2 3 4 5]
+}
+
 func ExampleSlice_Replace_false() {
 	s := slice.FromRaw([]string{"one", "two", "two", "two"})
 
@@ -185,7 +203,7 @@ func ExampleSlice_Insert_false() {
 	fmt.Println(s.Insert(1, "one")) // the highest possible index to insert == len(s)
 
 	s = slice.FromRaw([]string{"zero", "one", "two"})
-	fmt.Println(s.Insert(-1, "minus one")) // index MUST be >= 0
+	fmt.Println(s.Insert(-100, "minus one")) // invalid index
 
 	// Output:
 	// false

slice.go

@@ -102,6 +102,8 @@ func (s *Slice[T]) DeleteOne(index int) (ok bool) {
 //	s.Delete(1, 3)
 //	fmt.Println(s) [1 5]
 func (s *Slice[T]) Delete(index int, length int) (ok bool) {
+	index = s.solveIndex(index)
+
 	if index < 0 || *s == nil || index+length > len(*s) {
 		return false
 	}
@@ -120,6 +122,8 @@ func (s *Slice[T]) Delete(index int, length int) (ok bool) {
 //	s.Insert(1 "two", "three")
 //	fmt.Println(s) // ["one", "two", "three", "four"]
 func (s *Slice[T]) Insert(index int, v ...T) (ok bool) {
+	index = s.solveIndex(index)
+
 	if index < 0 || index > len(*s) {
 		return false
 	}
@@ -144,6 +148,8 @@ func (s *Slice[T]) Insert(index int, v ...T) (ok bool) {
 //	s.Replace(2, "three", "four", "five")
 //	fmt.Println(s) // [one two three four five]
 func (s *Slice[T]) Replace(index int, v ...T) (ok bool) {
+	index = s.solveIndex(index)
+
 	if index < 0 || index+len(v) > len(*s) {
 		return false
 	}
@@ -201,9 +207,7 @@ func (s *Slice[T]) Filter(keep func(index int, val T) bool) {
 //	val, ok := x.Get(-1)
 //	fmt.Println(val) // 5
 func (s *Slice[T]) Get(index int) (_ T, ok bool) {
-	if index < 0 {
-		index += len(*s)
-	}
+	index = s.solveIndex(index)
 
 	if index < 0 || index >= len(*s) {
 		var r T
@@ -240,3 +244,11 @@ func (s *Slice[T]) Shuffle(randIntN func(n int) int) {
 		(*s)[i], (*s)[j] = (*s)[j], (*s)[i]
 	}
 }
+
+func (s *Slice[T]) solveIndex(i int) int {
+	if i < 0 {
+		i += len(*s)
+	}
+
+	return i
+}