slices: add examples for iterator-related functions

Change-Id: I13e878579b51638c2c07ad3ea99be7276177875c
Reviewed-on: https://go-review.googlesource.com/c/go/+/603735
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/slices/example_test.go b/src/slices/example_test.go
index cb601ada0ade65f3b0aeb903068630b0cb4bee5f..fb93f6e79f589435a580bacc1dc45aa5d5c297de 100644 (file)
--- a/src/slices/example_test.go
+++ b/src/slices/example_test.go
@@ -385,6 +385,133 @@ func ExampleRepeat() {
        // [0 1 2 3 0 1 2 3]
 }
 
+func ExampleAll() {
+       names := []string{"Alice", "Bob", "Vera"}
+       for i, v := range slices.All(names) {
+               fmt.Println(i, ":", v)
+       }
+       // Output:
+       // 0 : Alice
+       // 1 : Bob
+       // 2 : Vera
+}
+
+func ExampleBackward() {
+       names := []string{"Alice", "Bob", "Vera"}
+       for i, v := range slices.Backward(names) {
+               fmt.Println(i, ":", v)
+       }
+       // Output:
+       // 2 : Vera
+       // 1 : Bob
+       // 0 : Alice
+}
+
+func ExampleValues() {
+       names := []string{"Alice", "Bob", "Vera"}
+       for v := range slices.Values(names) {
+               fmt.Println(v)
+       }
+       // Output:
+       // Alice
+       // Bob
+       // Vera
+}
+
+func ExampleAppendSeq() {
+       seq := func(yield func(int) bool) {
+               for i := 0; i < 10; i += 2 {
+                       if !yield(i) {
+                               return
+                       }
+               }
+       }
+
+       s := slices.AppendSeq([]int{1, 2}, seq)
+       fmt.Println(s)
+       // Output:
+       // [1 2 0 2 4 6 8]
+}
+
+func ExampleCollect() {
+       seq := func(yield func(int) bool) {
+               for i := 0; i < 10; i += 2 {
+                       if !yield(i) {
+                               return
+                       }
+               }
+       }
+
+       s := slices.Collect(seq)
+       fmt.Println(s)
+       // Output:
+       // [0 2 4 6 8]
+}
+
+func ExampleSorted() {
+       seq := func(yield func(int) bool) {
+               flag := -1
+               for i := 0; i < 10; i += 2 {
+                       flag = -flag
+                       if !yield(i * flag) {
+                               return
+                       }
+               }
+       }
+
+       s := slices.Sorted(seq)
+       fmt.Println(s)
+       fmt.Println(slices.IsSorted(s))
+       // Output:
+       // [-6 -2 0 4 8]
+       // true
+}
+
+func ExampleSortedFunc() {
+       seq := func(yield func(int) bool) {
+               flag := -1
+               for i := 0; i < 10; i += 2 {
+                       flag = -flag
+                       if !yield(i * flag) {
+                               return
+                       }
+               }
+       }
+
+       sortFunc := func(a, b int) int {
+               return cmp.Compare(b, a) // the comparison is being done in reverse
+       }
+
+       s := slices.SortedFunc(seq, sortFunc)
+       fmt.Println(s)
+       // Output:
+       // [8 4 0 -2 -6]
+}
+
+func ExampleSortedStableFunc() {
+       type Person struct {
+               Name string
+               Age  int
+       }
+
+       people := []Person{
+               {"Gopher", 13},
+               {"Alice", 20},
+               {"Bob", 5},
+               {"Vera", 24},
+               {"Zac", 20},
+       }
+
+       sortFunc := func(x, y Person) int {
+               return cmp.Compare(x.Age, y.Age)
+       }
+
+       s := slices.SortedStableFunc(slices.Values(people), sortFunc)
+       fmt.Println(s)
+       // Output:
+       // [{Bob 5} {Gopher 13} {Alice 20} {Zac 20} {Vera 24}]
+}
+
 func ExampleChunk() {
        type Person struct {
                Name string