adag-call-by-sharing.md

Call by Sharing

#python #programming #carefully

• Copy the references of the objects, alias for the original
• Change the mutable ones and maintain unchangeable the one that is immutable
• "Principle of the least astonishment"

class TwilightBus:
    """A bus model that makes passengers vanish"""
    def __init__(self, passengers=None):
 ef __init__(self, passengers=None):
        if passengers is None:
            self.passengers = []
        else:
            self.passengers = list(passengers)
    def pick(self, name):
        self.passengers.append(name)
    def drop(self, name):
        self.passengers.remove(name)

Warning

BUG: Parameters with mutable types as default is a source of bug

References

• Ramalho, 2022, p213-218