Merge pull request #851 from devlights/add-ring-index-example

examples/singleapp/ring_index/Taskfile.yml

@@ -0,0 +1,8 @@
+# https://taskfile.dev
+
+version: '3'
+
+tasks:
+  default:
+    cmds:
+      - go run .

examples/singleapp/ring_index/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+)
+
+type (
+	ring struct {
+		curr int
+		last int
+		next int
+	}
+)
+
+func newRing() *ring {
+	return &ring{curr: 0, last: 2, next: 1}
+}
+
+func (me *ring) rotate() {
+	me.curr = (me.curr + 1) % 3
+	me.last = (me.last + 1) % 3
+	me.next = (me.next + 1) % 3
+}
+
+func (me *ring) String() string {
+	return fmt.Sprintf("(curr=%d,last=%d,next=%d)", me.curr, me.last, me.next)
+}
+
+func main() {
+	log.SetFlags(0)
+
+	ctx := context.Background()
+	if err := run(ctx); err != nil {
+		log.Panic(err)
+	}
+}
+
+func run(ctx context.Context) error {
+	var (
+		r = newRing()
+	)
+
+	for range 10 {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
+		log.Println(r)
+		r.rotate()
+	}
+
+	return nil
+}