fix: address misc issues (#84)

README.md

@@ -321,7 +321,7 @@ var States = am.Struct{
 
 - [godoc](https://godoc.org/github.com/pancsta/asyncmachine-go/pkg/machine)
 - [cookbook](/docs/cookbook.md)
-- [manual](/docs/manual.md)
+- [manual](/docs/manual.md) ([pdf](/assets/manual.pdf))
   - [Machine and States](/docs/manual.md#machine-and-states)
       - [State Clocks and Context](/docs/manual.md#state-clocks-and-context)
       - [Auto States](/docs/manual.md#auto-states)
@@ -401,13 +401,14 @@ See [`tools/cmd/am-gen`](tools/cmd/am-gen/README.md) for more info.
 ![TUI Debugger](assets/am-dbg.png)
 
 `am-dbg` is a lightweight, multi-client debugger for AM. It easily handles >100
- client machines simultaneously (and potentially many more). Some features include:
+ client machines simultaneously streaming telemetry data (and potentially many more). Some features include:
 
 - states tree
 - log view
 - time travel
 - transition steps
 - import / export
+- filters
 - matrix view
 
 See [`tools/cmd/am-dbg`](tools/cmd/am-dbg/README.md) for more info.
@@ -488,7 +489,7 @@ for more info.
 
 ### am-dbg
 
-am-dbg is a [tview](https://github.com/rivo/tview/) TUI app with a single machine consisting of:
+am-dbg is a [cview](https://code.rocket9labs.com/tslocum/cview) TUI app with a single machine consisting of:
 
 - input events (7 states)
 - external state (11 states)

Taskfile.yml

@@ -25,32 +25,33 @@ tasks:
       - task: build-telemetry
       - task: build-debugger
 
-  debugger:
+  am-dbg:
     silent: false
     cmds:
       - go run tools/cmd/am-dbg/main.go {{.CLI_ARGS}}
 
-  debugger-assets:
+  am-dbg-asset:
     silent: false
     cmds:
-      - |
-        go run tools/cmd/am-dbg/main.go \
-          --import-data assets/am-dbg-dump-sim.gob.bz2 \
+      - go run tools/cmd/am-dbg/main.go
+          --import-data assets/am-dbg-sim.gob.bz2
           {{.CLI_ARGS}}
 
-  debugger-client:
+  am-dbg-dump:
+    silent: false
     cmds:
-      - go run tools/cmd/am-dbg/main.go 
-          --log-level 2
-          --am-dbg-url localhost:9913
+      - go run tools/cmd/am-dbg/main.go
+          --import-data am-dbg-dump.gob.bz2
+          {{.CLI_ARGS}}
 
-  debugger-debugger:
+  am-dbg-dbg:
     cmds:
       - go run tools/cmd/am-dbg/main.go 
           --log-file am-dbg-dbg.log 
           --log-level 2
           --listen-on localhost:9913
           --select-connected
+          {{.CLI_ARGS}}
 
   test:
     cmds:
@@ -169,7 +170,6 @@ tasks:
 
   gen-states-file:
     desc: Generate states file for provided state names, eg "task gen-states-file -- Foo,Bar"
-    example: task gen-states-file --state-names "state1,state2,state3"
     cmds:
       - go run tools/cmd/am-gen/main.go states-file {{.CLI_ARGS}}
 

docs/cookbook.md

@@ -451,7 +451,8 @@ import (
 )
 
 func main() {
-    m := am.New(nil, ss.States, nil)
+    ctx := context.Background()
+    m := am.New(ctx, ss.States, nil)
     err := m.VerifyStates(ss.Names)
     if err != nil {
         print(err)
@@ -549,7 +550,6 @@ func Msg(msgTx *Msg) {
     // enqueue
     queue = append(queue, msgTx)
 }
-
 ```
 
 ### Switch a state group

examples/nfa/nfa_test.go

@@ -155,10 +155,10 @@ func (t *Regexp) input1(mach *am.Machine) {
 
 // example
 
-func TestRegexp(t *testing.T) {
+func TestNFA(t *testing.T) {
 	var err error
 	mach := am.New(context.Background(), states, &am.Opts{
-		ID:                   "regexp",
+		ID:                   "nfa",
 		DontPanicToException: true,
 		DontLogID:            true,
 		LogLevel:             am.LogChanges,

pkg/history/history.go

@@ -12,6 +12,8 @@ import (
 )
 
 type History struct {
+	*am.NoOpTracer
+
 	Entries []Entry
 	// LastActivated is a map of state names to the last time they were activated
 	LastActivated map[string]time.Time
@@ -22,27 +24,15 @@ type History struct {
 	maxEntries int
 }
 
-func (h *History) TransitionInit(transition *am.Transition) {}
-func (h *History) HandlerStart(transition *am.Transition, emitter string,
-	handler string) {
-}
-
-func (h *History) HandlerEnd(transition *am.Transition, emitter string,
-	handler string) {
-}
-func (h *History) End()                                   {}
-func (h *History) MachineInit(mach *am.Machine)           {}
-func (h *History) NewSubmachine(parent, mach *am.Machine) {}
 func (h *History) Inheritable() bool {
 	return false
 }
-func (h *History) MachineDispose(machID string) {}
-func (h *History) QueueEnd(mach *am.Machine)    {}
 
 func (h *History) TransitionEnd(tx *am.Transition) {
 	if !tx.Accepted {
 		return
 	}
+
 	mut := tx.Mutation
 	match := false
 	for _, name := range h.States {
@@ -54,6 +44,7 @@ func (h *History) TransitionEnd(tx *am.Transition) {
 	if !match {
 		return
 	}
+
 	// rotate TODO optimize rotation
 	if len(h.Entries) >= h.maxEntries {
 		cutFrom := len(h.Entries) - h.maxEntries
@@ -169,12 +160,14 @@ func Track(mach *am.Machine, states am.S, maxEntries int) *History {
 		States:        states,
 		maxEntries:    maxEntries,
 	}
+
 	// mark active states as activated to reflect the current state
 	for _, name := range states {
 		if mach.Is1(name) {
 			history.LastActivated[name] = time.Now()
 		}
 	}
 	mach.Tracers = append(mach.Tracers, history)
+
 	return history
 }

pkg/machine/machine.go

@@ -1,15 +1,8 @@
 // Package machine is a general purpose state machine for managing complex
 // async workflows in a safe and structured way.
 //
-// It can be used as a lightweight in-memory Temporal [1] alternative, worker
-// for Asynq [2], or to write simple consensus engines, stateful firewalls,
-// telemetry, bots, etc.
-//
-// The project itself is a minimal implementation of AsyncMachine in Golang
+// It's a dependency-free implementation of AsyncMachine in Golang
 // using channels and context. It aims at simplicity and speed.
-//
-// [1]: https://github.com/temporalio/temporal
-// [2]: https://github.com/hibiken/asynq
 package machine // import "github.com/pancsta/asyncmachine-go/pkg/machine"
 
 import (
@@ -29,7 +22,7 @@ import (
 // Machine represent states, provides mutation methods, helpers methods and
 // info about the current and scheduled transitions (if any).
 type Machine struct {
-	// Unique ID of this machine. Default: random ID.
+	// Unique ID of this machine. Default: random ID. Read-only.
 	ID string
 	// Time for a handler to execute. Default: time.Second
 	HandlerTimeout time.Duration
@@ -400,7 +393,7 @@ func (m *Machine) disposeEmitter(emitter *emitter) {
 // ctx: optional context defaults to the machine's context.
 func (m *Machine) WhenErr(ctx context.Context) <-chan struct{} {
 	// handle with a shared channel with broadcast via close
-	return m.When([]string{"Exception"}, ctx)
+	return m.When([]string{Exception}, ctx)
 }
 
 // When returns a channel that will be closed when all the passed states
@@ -444,36 +437,7 @@ func (m *Machine) When(states S, ctx context.Context) <-chan struct{} {
 	}
 
 	// dispose with context
-	// TODO extract
-	if ctx != nil {
-		go func() {
-			select {
-			case <-ch:
-				return
-			case <-m.Ctx.Done():
-				return
-			case <-ctx.Done():
-			}
-
-			// GC only if needed
-			if m.Disposed {
-				return
-			}
-
-			m.activeStatesLock.Lock()
-			defer m.activeStatesLock.Unlock()
-
-			for _, s := range states {
-				if _, ok := m.indexWhen[s]; ok {
-					if len(m.indexWhen[s]) == 1 {
-						delete(m.indexWhen, s)
-					} else {
-						m.indexWhen[s] = slicesWithout(m.indexWhen[s], binding)
-					}
-				}
-			}
-		}()
-	}
+	diposeWithCtx(m, ctx, ch, states, binding, &m.activeStatesLock, m.indexWhen)
 
 	// insert the binding
 	for _, s := range states {
@@ -996,7 +960,7 @@ func (m *Machine) queueMutation(mutationType MutationType, states S, args A) {
 	statesParsed := m.MustParseStates(states)
 	// Detect duplicates and avoid queueing them.
 	if len(args) == 0 && m.detectQueueDuplicates(mutationType, statesParsed) {
-		m.log(LogOps, "[queue:skipped] Duplicate detected for [%s] '%s'",
+		m.log(LogOps, "[queue:skipped] Duplicate detected for [%s] %s",
 			mutationType, j(statesParsed))
 		return
 	}
@@ -1158,6 +1122,7 @@ func (m *Machine) BindHandlers(handlers any) error {
 //
 // It's not supported to nest OnEvent() calls, as it would cause a deadlock.
 // Using OnEvent is recommended only in special cases, like test assertions.
+// The Tracer API is a better way to event feeds.
 func (m *Machine) OnEvent(events []string, ctx context.Context) chan *Event {
 	ch := make(chan *Event, 50)
 	if m.Disposed {
@@ -1855,7 +1820,11 @@ func (m *Machine) processEmitters(e *Event) (Result, bool) {
 			timeout: false,
 		}
 		m.handlerTimer.Reset(m.HandlerTimeout)
-		m.handlerStart <- handler
+		select {
+		case <-m.Ctx.Done():
+			break
+		case m.handlerStart <- handler:
+		}
 
 		// wait on the result / timeout / context
 		select {
@@ -1942,7 +1911,13 @@ func (m *Machine) handlerLoop() {
 				continue
 			}
 
-			m.handlerEnd <- ret
+			select {
+			case <-m.Ctx.Done():
+				// dispose with context
+				m.Dispose()
+				return
+			case m.handlerEnd <- ret:
+			}
 		}
 	}
 }
@@ -1994,9 +1969,9 @@ func (m *Machine) processWhenArgs(e *Event) {
 	}
 }
 
-// detectQueueDuplicates checks for duplicated mutations without params.
-// 1. Check if a mutation is scheduled
-// 2. Check if a counter mutation isn't scheduled later
+// detectQueueDuplicates checks for duplicated mutations
+// 1. Check if a mutation is scheduled (without params)
+// 2. Check if a counter mutation isn't scheduled later (any params)
 func (m *Machine) detectQueueDuplicates(mutationType MutationType,
 	parsed S,
 ) bool {
@@ -2332,7 +2307,7 @@ func (m *Machine) CanRemove(states S) bool {
 	panic("CanRemove not implemented; github.com/pancsta/asyncmachine-go/pulls")
 }
 
-// Clocks returns the map of specified cloks or all clocks if states is nil.
+// Clocks returns the map of specified clocks or all clocks if states is nil.
 func (m *Machine) Clocks(states S) Clocks {
 	if states == nil {
 		return maps.Clone(m.clock)