feat(skiplist): iterator

skiplists/example_iter_test.go

@@ -0,0 +1,30 @@
+//go:build goexperiment.rangefunc
+
+package skiplists_test
+
+import (
+	"fmt"
+
+	"github.com/houz42/abstract/skiplists"
+)
+
+func ExampleSkipList_All() {
+	list := skiplists.New[string]()
+
+	list.Insert("Hello")
+	list.Insert("gopher")
+	list.Insert("Go")
+	list.Insert("is")
+	list.Insert("fun")
+
+	for i, v := range list.All() {
+		fmt.Println(i, v)
+	}
+
+	// Output:
+	// 0 Go
+	// 1 Hello
+	// 2 fun
+	// 3 gopher
+	// 4 is
+}

skiplists/skiplists_iter.go

@@ -0,0 +1,20 @@
+//go:build goexperiment.rangefunc
+
+package skiplists
+
+import "iter"
+
+// All returns an iterator that yields all the ordered elements in the SkipList.
+func (sl *SkipList[V]) All() iter.Seq2[int, V] {
+	return func(yield func(int, V) bool) {
+		node := sl.head.next[0]
+		i := 0
+		for node != nil {
+			if !yield(i, node.val) {
+				return
+			}
+			i++
+			node = node.next[0]
+		}
+	}
+}