slice: remove the Split function

slice/example_test.go

@@ -18,20 +18,6 @@ func ExamplePartition() {
 	// [3 1 9 5 7]
 }
 
-func ExampleSplit() {
-	vs := []int{1, 2, 3, 4, 5, 6, 7, 8}
-
-	fmt.Println("input:", vs)
-	first3, tail := slice.Split(vs, 3)
-	head, last3 := slice.Split(vs, -3)
-	fmt.Println("first3:", first3, "tail:", tail)
-	fmt.Println("last3:", last3, "head:", head)
-	// Output:
-	// input: [1 2 3 4 5 6 7 8]
-	// first3: [1 2 3] tail: [4 5 6 7 8]
-	// last3: [6 7 8] head: [1 2 3 4 5]
-}
-
 func ExampleMatchingKeys() {
 	vs := map[string]int{"red": 3, "yellow": 6, "blue": 4, "green": 5}
 

slice/slice.go

@@ -109,18 +109,6 @@ func MapKeys[T comparable, U any](m map[T]U) []T {
 	return keys
 }
 
-// Split returns two subslices of ss, the first containing the elements prior
-// to index i, the second containing the elements from index i to the end.
-// If i < 0, offsets are counted backward from the end.  If i is out of range,
-// Split will panic.
-func Split[T any, Slice ~[]T](ss Slice, i int) (lhs, rhs Slice) {
-	b, ok := sliceCheck(i, len(ss))
-	if !ok {
-		panic("index out of range")
-	}
-	return ss[:b], ss[b:]
-}
-
 func sliceCheck(i, n int) (int, bool) {
 	if i < 0 {
 		i += n

slice/slice_test.go

@@ -103,42 +103,6 @@ func TestMapKeys(t *testing.T) {
 	}
 }
 
-func TestSplit(t *testing.T) {
-	tests := []struct {
-		input    string
-		i        int
-		lhs, rhs []string
-	}{
-		{"", 0, nil, nil},
-		{"a", 0, nil, []string{"a"}},
-		{"a", 1, []string{"a"}, nil},
-		{"a b c", 0, nil, []string{"a", "b", "c"}},
-		{"a b c", 1, []string{"a"}, []string{"b", "c"}},
-		{"a b c", 2, []string{"a", "b"}, []string{"c"}},
-		{"a b c", 3, []string{"a", "b", "c"}, nil},
-		{"a b c d", -1, []string{"a", "b", "c"}, []string{"d"}},
-		{"a b c d", -2, []string{"a", "b"}, []string{"c", "d"}},
-		{"a b c d", -3, []string{"a"}, []string{"b", "c", "d"}},
-		{"a b c d", -4, nil, []string{"a", "b", "c", "d"}},
-	}
-	for _, tc := range tests {
-		input := strings.Fields(tc.input)
-		lhs, rhs := slice.Split(input, tc.i)
-		if diff := cmp.Diff(tc.lhs, lhs, cmpopts.EquateEmpty()); diff != "" {
-			t.Errorf("Split %q %d lhs (-want, +got):\n%s", input, tc.i, diff)
-		}
-		if diff := cmp.Diff(tc.rhs, rhs, cmpopts.EquateEmpty()); diff != "" {
-			t.Errorf("Split %q %d rhs (-want, +got):\n%s", input, tc.i, diff)
-		}
-	}
-	t.Run("Range", func(t *testing.T) {
-		mtest.MustPanic(t, func() { slice.Split([]string(nil), 1) })
-		mtest.MustPanic(t, func() { slice.Split([]string(nil), -1) })
-		mtest.MustPanic(t, func() { slice.Split([]int{1, 2, 3}, 4) })
-		mtest.MustPanic(t, func() { slice.Split([]int{1, 2, 3}, -4) })
-	})
-}
-
 func TestMatchingKeys(t *testing.T) {
 	even := func(z int) bool { return z%2 == 0 }
 	big := func(z int) bool { return z > 10 }