Guido's new method definition idea

Daniel Fetchinson fetchinson at
Sat Dec 6 03:21:18 CET 2008

Hi folks,

The story of the explicit self in method definitions has been
discussed to death and we all know it will stay. However, Guido
himself acknowledged that an alternative syntax makes perfect sense
and having both (old and new) in a future version of python is a
possibility since it maintains backward compatibility. The alternative
syntax will be syntactic sugar for the old one. This blog post of his
is what I'm talking about:

The proposal is to allow this:

class C:
    def self.method( arg ):
        self.value = arg
        return self.value

instead of this:

class C:
    def method( self, arg ):
        self.value = arg
        return self.value

I.e. explicit self stays only the syntax is slightly different and may
seem attractive to some. As pointed out by Guido classmethods would
work similarly:

class C:
    def cls.method( arg ):
        cls.val = arg
        return cls.val

The fact that Guido says,

"Now, I'm not saying that I like this better than the status quo. But
I like it a lot better than [...] but it has the great advantage that
it is backward compatible, and can be evolved into a PEP with a
reference implementation without too much effort."

shows that the proposal is viable.

I'd like this new way of defining methods, what do you guys think?
Anyone ready for writing a PEP?


Psss, psss, put it down! -

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