Add events

examples/events_and_messages/cars.py

@@ -0,0 +1,141 @@
+from __future__ import annotations
+from soil import *
+from soil import events
+from mesa.space import MultiGrid
+from enum import Enum
+
+
+@dataclass
+class Journey:
+    origin: (int, int)
+    destination: (int, int)
+    tip: float
+
+    passenger: Passenger = None
+    driver: Driver = None
+
+
+class City(EventedEnvironment):
+    def __init__(self, *args, n_cars=1, height=100, width=100,  n_passengers=10, agents=None, **kwargs):
+        self.grid = MultiGrid(width=width, height=height, torus=False)
+        if agents is None:
+            agents = []
+            for i in range(n_cars):
+                agents.append({'agent_class': Driver})
+            for i in range(n_passengers):
+                agents.append({'agent_class': Passenger})
+        super().__init__(*args, agents=agents, **kwargs)
+        for agent in self.agents:
+            self.grid.place_agent(agent, (0, 0))
+            self.grid.move_to_empty(agent)
+
+class Driver(Evented, FSM):
+    pos = None
+    journey = None
+    earnings = 0
+
+    def on_receive(self, msg, sender):
+        if self.journey is None and isinstance(msg, Journey) and msg.driver is None:
+            msg.driver = self
+            self.journey = msg
+
+    @default_state
+    @state
+    def wandering(self):
+        target = None
+        self.check_passengers()
+        self.journey = None
+        while self.journey is None:
+            if target is None or not self.move_towards(target):
+                target = self.random.choice(self.model.grid.get_neighborhood(self.pos, moore=False))
+            self.check_passengers()
+            self.check_messages() # This will call on_receive behind the scenes
+            yield Delta(30)
+        try:
+            self.journey = yield self.journey.passenger.ask(self.journey, timeout=60)
+        except events.TimedOut:
+            self.journey = None
+            return
+        return self.driving
+
+    def check_passengers(self):
+        c = self.count_agents(agent_class=Passenger)
+        self.info(f"Passengers left {c}")
+        if not c:
+            self.die()
+
+    @state
+    def driving(self):
+        #Approaching
+        while self.move_towards(self.journey.origin):
+            yield
+        while self.move_towards(self.journey.destination, with_passenger=True):
+            yield
+        self.check_passengers()
+        return self.wandering
+
+    def move_towards(self, target, with_passenger=False):
+        '''Move one cell at a time towards a target'''
+        self.info(f"Moving { self.pos } -> { target }")
+        if target[0] == self.pos[0] and target[1] == self.pos[1]:
+            return False
+
+        next_pos = [self.pos[0], self.pos[1]]
+        for idx in [0, 1]:
+            if self.pos[idx] < target[idx]:
+                next_pos[idx] += 1
+                break
+            if self.pos[idx] > target[idx]:
+                next_pos[idx] -= 1
+                break
+        self.model.grid.move_agent(self, tuple(next_pos))
+        if with_passenger:
+            self.journey.passenger.pos = self.pos  # This could be communicated through messages
+        return True
+            
+
+class Passenger(Evented, FSM):
+    pos = None
+
+    @default_state
+    @state
+    def asking(self):
+        destination = (self.random.randint(0, self.model.grid.height), self.random.randint(0, self.model.grid.width))
+        self.journey = None
+        journey = Journey(origin=self.pos,
+                          destination=destination,
+                          tip=self.random.randint(10, 100),
+                          passenger=self)
+
+        timeout = 60
+        expiration = self.now + timeout
+        self.model.broadcast(journey, ttl=timeout, sender=self, agent_class=Driver)
+        while not self.journey:
+            self.info(f"Passenger at: { self.pos }. Checking for responses.")
+            try:
+                yield self.received(expiration=expiration)
+            except events.TimedOut:
+                self.info(f"Passenger at: { self.pos }. Asking for journey.")
+                self.model.broadcast(journey, ttl=timeout, sender=self, agent_class=Driver)
+                expiration = self.now + timeout
+            self.check_messages()
+        return self.driving_home
+
+    def on_receive(self, msg, sender):
+        if isinstance(msg, Journey):
+            self.journey = msg
+            return msg
+
+    @state
+    def driving_home(self):
+        while self.pos[0] != self.journey.destination[0] or self.pos[1] != self.journey.destination[1]:
+            yield self.received(timeout=60)
+        self.info("Got home safe!")
+        self.die()
+
+
+simulation = Simulation(model_class=City, model_params={'n_passengers': 2})
+
+if __name__ == "__main__":
+    with easy(simulation) as s:
+        s.run()