fix(examples:wait_group): shared receiver; fix(runtime:funcs): sendin…

…g nil as msg caused panic;

.vscode/launch.json

@@ -1,14 +1,14 @@
 {
   "version": "0.2.0",
   "configurations": [
-    // {
-    //   "name": "Debug Compiled Go",
-    //   "type": "go",
-    //   "request": "launch",
-    //   "mode": "auto",
-    //   "program": "${workspaceFolder}/dist/main.go",
-    //   "cwd": "${workspaceFolder}/dist"
-    // },
+    {
+      "name": "Debug Compiled Go",
+      "type": "go",
+      "request": "launch",
+      "mode": "auto",
+      "program": "${workspaceFolder}/examples/dist/main.go",
+      "cwd": "${workspaceFolder}/examples"
+    },
     {
       "name": "RUN",
       "type": "go",

examples/wait_group/main.neva

@@ -1,14 +1,15 @@
 import { sync }
 
 flow Main(start) (stop) {
-  wg sync.WaitGroup
-  Println
-  ---
-  :start -> [
-    ('Hello' -> println -> wg:sig),
-    ('Neva' -> println -> wg:sig),
-    ('World!' -> println -> wg:sig)
-  ]
-  3 -> wg:count
-  wg -> :stop
-}
+	p1 Println, p2 Println, p3 Println
+	wg sync.WaitGroup
+	---
+	:start -> [
+		('Hello' -> p1),
+		('Neva' -> p2),
+		('World!' -> p3)
+	]
+	[p1, p2, p3] -> wg:sig
+	3 -> wg:count
+	wg -> :stop
+}

internal/compiler/backend/golang/tpl.go

@@ -42,7 +42,6 @@ func main() {
     if err != nil {
         panic(err)
     }
-
     defer func() {
         if err := close(); err != nil {
             panic(err)

internal/runtime/funcs/time_sleep.go

@@ -29,7 +29,7 @@ func (timeAfter) Create(io runtime.IO, _ runtime.Msg) (func(ctx context.Context)
 
 			time.Sleep(time.Duration(durMsg.Int()))
 
-			if !sigOut.Send(ctx, nil) {
+			if !sigOut.Send(ctx, emptyStruct()) {
 				return
 			}
 		}

internal/runtime/funcs/unwrap.go

@@ -32,7 +32,7 @@ func (unwrap) Create(io runtime.IO, _ runtime.Msg) (func(ctx context.Context), e
 			}
 
 			if dataMsg == nil {
-				if !noneOut.Send(ctx, nil) {
+				if !noneOut.Send(ctx, emptyStruct()) {
 					return
 				}
 				continue

internal/runtime/funcs/utils.go

@@ -22,3 +22,7 @@ func streamItem(data runtime.Msg, idx int64, last bool) runtime.StructMsg {
 		[]runtime.Msg{data, runtime.NewIntMsg(idx), runtime.NewBoolMsg(last)},
 	)
 }
+
+func emptyStruct() runtime.StructMsg {
+	return emptyStruct()
+}

internal/runtime/funcs/wait_group.go

@@ -45,7 +45,7 @@ func (waitGroup) Handle(
 				}
 			}
 
-			if !sigOut.Send(ctx, nil) {
+			if !sigOut.Send(ctx, emptyStruct()) {
 				return
 			}
 		}

internal/runtime/funcs/write_all.go

@@ -50,7 +50,7 @@ func (c writeAll) Create(rio runtime.IO, _ runtime.Msg) (func(ctx context.Contex
 				continue
 			}
 
-			if !sig.Send(ctx, nil) {
+			if !sig.Send(ctx, emptyStruct()) {
 				return
 			}
 		}

internal/runtime/interceptors.go

@@ -45,6 +45,9 @@ func (d *DebugInterceptor) Received(receiver PortSlotAddr, msg Msg) Msg {
 }
 
 func (d DebugInterceptor) formatMsg(msg Msg) string {
+	if msg.Str() != "" {
+		return fmt.Sprintf("%q", msg.Str())
+	}
 	return fmt.Sprint(msg)
 }
 

internal/runtime/runtime.go

@@ -32,7 +32,10 @@ func Run(ctx context.Context, prog Program, registry map[string]FuncCreator) err
 		close(funcsFinished)
 	}()
 
-	prog.Start.Send(ctx, &baseMsg{}) // lock until some node receive
+	prog.Start.Send(
+		ctx,
+		NewStructMsg(nil, nil),
+	)
 
 	<-funcsFinished