Add coroutines and iterators

coro/coro.go

@@ -0,0 +1,108 @@
+package coro
+
+import (
+	"slices"
+)
+
+const routineCancelled = "coroutine cancelled"
+
+type Yield func()
+
+func New(resume func(yield Yield)) *Routine[struct{}] {
+	return WithReturn(func(y YieldReturn[struct{}]) {
+		resume(func() {
+			y(struct{}{})
+		})
+	})
+}
+
+type YieldReturn[V any] func(V)
+
+func WithReturn[V any](resume func(YieldReturn[V])) *Routine[V] {
+	r := &Routine[V]{ // 1 alloc
+		resumed: make(chan struct{}), // 1 alloc
+		done:    make(chan V),        // 1 alloc
+		status:  Suspended,
+	}
+	go r.start(resume) // 3 allocs
+
+	return r
+}
+
+type Routine[V any] struct {
+	done    chan V
+	resumed chan struct{}
+	status  Status
+}
+
+func (r *Routine[V]) start(f func(YieldReturn[V])) { // 1 alloc
+	defer r.recoverAndDestroy()
+
+	_, ok := <-r.resumed // 2 allocs
+	if !ok {
+		panic(routineCancelled)
+	}
+
+	r.status = Running
+	f(r.yield)
+}
+
+func (r *Routine[V]) yield(v V) {
+	r.done <- v
+	r.status = Suspended
+	if _, ok := <-r.resumed; !ok {
+		panic(routineCancelled)
+	}
+}
+
+func (r *Routine[V]) recoverAndDestroy() {
+	p := recover()
+	if p != nil && p != routineCancelled {
+		panic("coroutine panicked")
+	}
+	r.status = Dead
+	close(r.done)
+}
+
+func (r *Routine[V]) Resume() (value V, hasMore bool) {
+	if r.status == Dead {
+		return
+	}
+
+	r.resumed <- struct{}{}
+	value, hasMore = <-r.done
+	return
+}
+
+func (r *Routine[V]) Status() Status {
+	return r.status
+}
+
+func (r *Routine[V]) Cancel() {
+	if r.status == Dead {
+		return
+	}
+
+	close(r.resumed)
+	<-r.done
+}
+
+type Status string
+
+const (
+	// Normal    Status = "normal"    // This coroutine is currently waiting in coresume for another coroutine. (Either for the running coroutine, or for another normal coroutine)
+	Running   Status = "running"   // This is the coroutine that's currently running - aka the one that just called costatus.
+	Suspended Status = "suspended" // This coroutine is not running - either it has yielded or has never been resumed yet.
+	Dead      Status = "dead"      // This coroutine has either returned or died due to an error.
+)
+
+type Routines []*Routine[struct{}]
+
+func (r Routines) ResumeAll() Routines {
+	for _, rout := range r {
+		rout.Resume()
+	}
+	return slices.DeleteFunc(r, func(r *Routine[struct{}]) bool {
+		return r.Status() == Dead
+	})
+}

coro/coro_bench_test.go

@@ -0,0 +1,78 @@
+package coro_test
+
+import (
+	"testing"
+
+	"github.com/elgopher/pi/coro"
+)
+
+func BenchmarkNew(b *testing.B) {
+	b.ReportAllocs()
+
+	var r *coro.Routine[struct{}]
+
+	for i := 0; i < b.N; i++ {
+		r = coro.New(f2) // 7 allocs :( 4us on windows :( But on linux it is 1us and 5 allocs!
+	}
+
+	_ = r
+}
+
+func BenchmarkCreate(b *testing.B) {
+	b.ReportAllocs()
+
+	var r *coro.Routine[struct{}]
+
+	for i := 0; i < b.N; i++ {
+		r = coro.WithReturn(f) // 6 allocs :( 4us on windows :( But on linux it is 1us and 5 allocs!
+	}
+
+	_ = r
+}
+
+func BenchmarkResume(b *testing.B) {
+	b.ReportAllocs()
+
+	var r *coro.Routine[struct{}]
+
+	for i := 0; i < b.N; i++ {
+		r = coro.WithReturn(f) // 6 allocs
+		r.Resume()             // 1 alloc, 0.8us :(
+	}
+	_ = r
+}
+
+func BenchmarkResumeUntilFinish(b *testing.B) {
+	b.ReportAllocs()
+
+	var r *coro.Routine[struct{}]
+
+	for i := 0; i < b.N; i++ {
+		r = coro.WithReturn(f) // 6 allocs
+		r.Resume()             // 1 alloc, 0.8us :(
+		r.Resume()             // 1 alloc, 0.8us :(
+	}
+	_ = r
+}
+
+func BenchmarkCancel(b *testing.B) {
+	b.ReportAllocs()
+
+	var r *coro.Routine[struct{}]
+
+	for i := 0; i < b.N; i++ {
+		r = coro.WithReturn(f) // 6 allocs
+		r.Cancel()             // -2 alloc????
+	}
+	_ = r
+}
+
+//go:noinline
+func f2(yield coro.Yield) {
+	yield()
+}
+
+//go:noinline
+func f(yield coro.YieldReturn[struct{}]) {
+	yield(struct{}{})
+}

examples/coroutine/coroutine.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"math/rand"
+	"net/http"
+
+	"github.com/elgopher/pi"
+	"github.com/elgopher/pi/coro"
+	"github.com/elgopher/pi/ebitengine"
+)
+
+var coroutines coro.Routines
+
+func main() {
+	go func() {
+		http.ListenAndServe("localhost:6060", nil)
+	}()
+
+	pi.Update = func() {
+		if pi.MouseBtnp(pi.MouseLeft) {
+			//r := movePixel(pi.MousePos)
+			for j := 0; j < 8000; j++ { // (~6-9KB per COROUTINE). Pico-8 has 4000 coroutines limit
+				r := coro.New(func(yield coro.Yield) {
+					sleep(10, yield)
+					moveHero(10, 120, 5, 10, yield)
+					sleep(20, yield)
+					moveHero(120, 10, 2, 10, yield)
+				})
+				coroutines = append(coroutines, r) // complexCoroutine is 2 coroutines - 12-18KB in total
+			}
+		}
+	}
+
+	pi.Draw = func() {
+		pi.Cls()
+		coroutines = coroutines.ResumeAll()
+		//devtools.Export("coroutines", coroutines)
+	}
+
+	ebitengine.Run()
+}
+
+func movePixel(pos pi.Position, yield coro.Yield) {
+	for i := 0; i < 64; i++ {
+		pi.Set(pos.X+i, pos.Y+i, byte(rand.Intn(16)))
+		yield()
+		yield()
+	}
+}
+
+func moveHero(startX, stopX, minSpeed, maxSpeed int, yield coro.Yield) {
+	anim := coro.WithReturn(randomMove(startX, stopX, minSpeed, maxSpeed))
+
+	for {
+		x, hasMore := anim.Resume()
+		pi.Set(x, 20, 7)
+		if hasMore {
+			yield()
+		} else {
+			return
+		}
+	}
+}
+
+// Reusable coroutine which returns int.
+func randomMove(start, stop, minSpeed, maxSpeed int) func(yield coro.YieldReturn[int]) {
+	pos := start
+
+	return func(yield coro.YieldReturn[int]) {
+		for {
+			speed := rand.Intn(maxSpeed - minSpeed)
+			if stop > start {
+				pos = pi.MinInt(stop, pos+speed) // move pos in stop direction by random speed
+			} else {
+				pos = pi.MaxInt(stop, pos-speed)
+			}
+
+			if pos == stop {
+				return
+			} else {
+				yield(pos)
+			}
+		}
+	}
+}
+
+func sleep(iterations int, yield coro.Yield) {
+	for i := 0; i < iterations; i++ {
+		yield()
+	}
+}