I'm reading Lutz & Ascher - Learn Python and I found this as a solution to one of the exercises:
class Lunch:
def __init__(self):
self.cust = Customer()
self.empl = Employee()
def order(self, foodName):
# start a Customer order simulation
self.cust.placeOrder(foodName, self.empl)
def result(self):
# ask the Customer what kind of Food it has
self.cust.printFood()
class Customer:
def __init__(self):
# initialize my food to None
self.food = None
def placeOrder(self, foodName, employee):
# place order with an Employee
self.food = employee.takeOrder(foodName)
def printFood(self):
# print the name of my food
print self.food.name
class Employee:
def takeOrder(self, foodName):
# return a Food, with requested name
return Food(foodName)
class Food:
def __init__(self, name):
# store food name
self.name = name
if __name__ == '__main__':
x = Lunch()
x.order('burritos')
x.result()
x.order('pizza')
x.result()`
What I don't understand is how the definition of the method placeOrder inside the customer class works, more specifically, there is no class employee (just Employee) whose method placeOrder could be used.
def placeOrder(self, foodName, employee):
# place order with an Employee
self.food = employee.takeOrder(foodName)
you may need to read a little bit about object oriented programming, and dynamic typing to grasp this. So basically, employee is an argument which will be passed at runtime, its type will be determined after the call to placeOrder. if you call PlaceOrder and put an instance of Employee or any class that has method takeOrder(), it will work. Imho, you should try to code an example from the beginning and test out what you learn, it will help you learn Python faster
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