Unification of Methods and Functions

[Delaney, Timothy C (Timothy)]

Antoon Pardon wrote:

> I'm a bit sick of this argument. There is a lot om implicity
> going on in python. if obj belongs to cls then obj.method()
> is syntactic sugar for cls.method(obj). That looks like
> a big implicite way to handle things in python.

Actually, they're not strictly the same. The instance knows which class
it is an instance of - that's why the syntactic sugar can work.

What you've stated is saying:

class C:
    def f (self):
        pass

c = C()

then c.f() is identical to calling C.f(c)

Now, in the above case that's correct. However, when subclasses get
introduced that goes out the door.

class D (C):
    def f (self):
        pass

d = D()

Now, d.f() is *not* identical to C.f(d). Instead it should be D.f(d).
Without knowing the class that d is an instance of, it is not possible
to call the correct method without the syntactic sugar.

d.f() is closer to syntactic sugar for d.__class__.f(d). However, even
that's not strictly correct, because c.f and d.f are bound methods -
they know which instance they are bound to without any further reference
to that instance.

Yes - there is a lot hidden here - but what is hidden is purely
implementation details.

Tim Delaney