Verbesserungen nach Testatversuch

go/TrafficLights/TrafficLight.go

@@ -1,5 +1,11 @@
 package main
 
+import (
+	"fmt"
+)
+
+var debuggingAllowed = true
+
 type CardinalDirection string
 
 const (
@@ -13,28 +19,12 @@ var Directions = []CardinalDirection{
 	north, south, east, west,
 }
 
-func nextDirection(currentDirection CardinalDirection) CardinalDirection {
-	switch currentDirection {
-	case north:
-		return east
-	case south:
-		return west
-	case east:
-		return south
-	case west:
-		return north
-	default:
-		return north
-		//TODO: dont return this here, return nil instead
-	}
-}
-
 type Colour string
 
 const (
-	red    = Colour("Red")
-	green  = Colour("Green")
-	yellow = Colour("Yellow")
+	red    = Colour("\u001B[31m Red \u001B[0m")
+	green  = Colour("\u001B[33m Green \u001B[0m")
+	yellow = Colour("\u001B[32m Yellow \u001B[0m")
 )
 
 var Colours = []Colour{
@@ -55,35 +45,53 @@ func nextColour(currentColour Colour) Colour {
 }
 
 func main() {
-	var directionChannel = make(chan CardinalDirection)
-	var colourChannel = make(chan Colour)
-	var waitChannel = make(chan string)
+	var quitChannel = make(chan string)
 
-	for _, direction := range Directions {
-		go TrafficLight(direction, directionChannel, colourChannel, waitChannel)
-	}
+	var northColour = make(chan Colour, 2)
+	var southColour = make(chan Colour, 2)
+	var eastColour = make(chan Colour, 2)
+	var westColour = make(chan Colour, 2)
 
-	directionChannel <- north
-	directionChannel <- south
+	var northDirection = make(chan string, 4)
+	var southDirection = make(chan string, 4)
+	var eastDirection = make(chan string, 4)
+	var westDirection = make(chan string, 4)
 
+	go TrafficLight(north, northColour, southColour, northDirection, eastDirection, southDirection)
+	go TrafficLight(south, southColour, northColour, southDirection, westDirection, northDirection)
+	go TrafficLight(east, eastColour, westColour, eastDirection, southDirection, westDirection)
+	go TrafficLight(west, westColour, eastColour, westDirection, northDirection, eastDirection)
+
+	<-quitChannel
 }
 
-func TrafficLight(direction CardinalDirection, directionChannel chan CardinalDirection, colourChannel chan Colour, waitChannel chan string) {
-	var colour Colour
+func TrafficLight(direction CardinalDirection, currentColour <-chan Colour, oppositeColour chan<- Colour, currentDirection <-chan string, nextDirection chan<- string, oppositeDirection chan<- string) {
+	var colour = red
+
+	if direction != north && direction != south {
+		nextDirection <- "go"
+	}
+
 	for {
-		switch msg := <-waitChannel; {
-		case msg == "proceed":
-			directionChannel <- nextDirection(direction)
+		show(direction, colour)
 
+		oppositeColour <- nextColour(colour)
+		select {
+		case msg := <-currentColour:
+			if msg == nextColour(colour) {
+				colour = msg
+			}
 		}
-		switch msg := <-directionChannel; {
-		case msg == direction:
 
-		}
-		colourChannel <- nextColour(colour)
-		switch msg := <-colourChannel; {
-		case msg == nextColour(colour):
-
-		}
+	}
+}
+
+func show(direction CardinalDirection, colour Colour) {
+	fmt.Println(string(direction), " : ", string(colour))
+}
+
+func debug(message string) {
+	if debuggingAllowed {
+		fmt.Println("Debug:", message)
 	}
 }

mCRL2/TrafficLights/v2/v2_spec.mcrl2

@@ -3,6 +3,22 @@
 sort
 	CardinalDirection = struct north | east | south | west;
 
+map
+	nextDirection: CardinalDirection -> CardinalDirection;
+	oppositeDirection : CardinalDirection -> CardinalDirection;
+
+eqn
+
+	nextDirection(north) = east;
+	nextDirection(east) = south;
+	nextDirection(south) = west;
+	nextDirection(west) = north;
+
+	oppositeDirection(north) = south;
+	oppositeDirection(south) = north;
+	oppositeDirection(east) = west;
+	oppositeDirection(west) = east;
+
 
 %-----------------------------------------------------------------------
 
@@ -40,7 +56,19 @@ sort
 map
 	combinations: Map;
 
+%------------------------------------------------------------------------
 
+map
+	unsafe : Map # CardinalDirection -> Bool;
+
+var
+	status: Map;
+	direction: CardinalDirection;
+
+eqn
+	unsafe(status, direction) = ((status(direction) in {green, yellow} || status(oppositeDirection(direction)) in {green, yellow})
+				 && (status(nextDirection(direction)) in {green, yellow}
+				|| status(oppositeDirection(nextDirection(direction))) in {green, yellow}));
 
 %------------------------------------------------------------------------
 
@@ -60,7 +88,7 @@ proc
 	;
 
 	Monitor(status : Map) = 
-		((status(north) in {green, yellow} || status(south) in {green, yellow}) && (status(east) in {green, yellow} || status(west) in {green, yellow})) %ist aktueller Zustand unsicher ?
+		(unsafe(status, north)) %ist aktueller Zustand unsicher ?
 			-> crossingUnsafe(status(north), status(east), status(south), status(west)) . delta %unsicherer Zustand, deadlock
 			
 		<>%wenn aktueller Zustand sicher:

mCRL2/TrafficLights/v3/v3_spec.mcrl2

@@ -3,6 +3,22 @@
 sort
 	CardinalDirection = struct north | east | south | west;
 
+map
+	nextDirection: CardinalDirection -> CardinalDirection;
+	oppositeDirection : CardinalDirection -> CardinalDirection;
+
+eqn
+
+	nextDirection(north) = east;
+	nextDirection(east) = south;
+	nextDirection(south) = west;
+	nextDirection(west) = north;
+
+	oppositeDirection(north) = south;
+	oppositeDirection(south) = north;
+	oppositeDirection(east) = west;
+	oppositeDirection(west) = east;
+
 %-----------------------------------------------------------------------
 
 sort
@@ -38,7 +54,20 @@ sort
 map
 	combinations: Map;
 
+%------------------------------------------------------------------------
 
+map
+	unsafe : Map # CardinalDirection # Colour -> Bool;
+
+var
+	status: Map;
+	direction: CardinalDirection;
+	colour: Colour;
+
+eqn
+	unsafe(status, direction, colour) = (colour in {green, yellow} || status(oppositeDirection(direction)) in {green, yellow})
+				 && (status(nextDirection(direction)) in {green, yellow}
+				|| status(oppositeDirection(nextDirection(direction))) in {green, yellow});
 
 %------------------------------------------------------------------------
 
@@ -59,17 +88,9 @@ proc
 	Monitor(status : Map) = 
 		sum direction : CardinalDirection.(
 			sum c : Colour .
-				(c == green) ->
-					(direction == north || direction == south) ->
-						((status(east) == red && status(west) == red) ->  % sind die anderen Ampeln rot ?
-							seeColour(direction, c) . Monitor(status= status[direction -> c])) % dann darf fortgefahren werden
-					<>
-						((status(north) == red && status(south) == red) ->
-							seeColour(direction, c) . Monitor(status= status[direction -> c]))
-				<> %soll nicht grün gezeigt werden kann einfach fortgefahren werden, es wurde ja bereits überprüft
-				seeColour(direction, c) .
-						Monitor(status= status[direction -> c])
-				 	
+				(unsafe(status, direction, c))
+				-> delta
+				<> seeColour(direction, c) . Monitor(status= status[direction -> c])
 	);
 
 

mCRL2/TrafficLights/v4/v4_spec.mcrl2

@@ -40,12 +40,13 @@ act
 %------------------------------------------------------------------------
 
 proc
-	TrafficLight(direction : CardinalDirection) = TL(direction, red, true);
+	TrafficLight(direction : CardinalDirection) =
+		(direction == north || direction == south)
+		-> TL(direction, red)
+		<> changeDirection(direction) . TL(direction, red)
+	;
 
-	TL(direction : CardinalDirection, colour : Colour, firstStart : Bool) =
-		(firstStart) %beim ersten Start nur das Licht umschalten
-		-> changeDirection(direction) . TL(direction, colour, false)
-		<> %ansonsten
+	TL(direction : CardinalDirection, colour : Colour) =
 			show(direction, colour) . %aktuellen Zustand zeigen
 			(colour == red) %wenn rot
 				-> wait . ChangeDirection(direction) %Richtungswechsel, wenn wieder zurück
@@ -61,7 +62,7 @@ proc
 	
 	ChangeLight(direction : CardinalDirection, colour : Colour) =
 		changeLight(nextColour(colour)) %zur nächsten Farbe wechseln, wenn beide Richtungen dies autorisieren
-		. TL(direction, nextColour(colour), false) %fortfahren
+		. TL(direction, nextColour(colour)) %fortfahren
 	;
 
 	System =
@@ -83,8 +84,8 @@ proc
 		},
 		
 
-		TrafficLight(north) || TrafficLight(east) || TrafficLight(south) || TrafficLight(west) || changeDirection(north) || changeDirection(south)
-		%starten der Prozesse und auslösen des ersten Richtungswechsels
+		TrafficLight(north) || TrafficLight(east) || TrafficLight(south) || TrafficLight(west)
+		%starten der Prozesse
 	)));
 
 init