[Python-Dev] PEP 318 - generality of list; restrictions on elements

[Skip Montanaro]

    Phillip> The way I see it, left-to-right helps reading what's happening
    Phillip> to the function.  For example:

    Phillip> def foo(cls,...) [contract(blah), classmethod]:
    Phillip>      ...

    Phillip> clearly says that a contract wrapper is being applied to foo,
    Phillip> and then it is being made a classmethod.

On the off-chance that a default arg initializer has side effects,
left-to-right also guarantees that the side effects take place before the
decorator expression is evaluated:

    i = I(...)

    def foo(a=i.func(...), b, c) [i.w1(...), w2]:
        ...

Evaluating i.func(...) might have some effect on the execution of i.w1(...).
I don't claim that's necessarily a good property to rely on, but if reading
order matches evaluation order it makes for fewer surprises.

    Phillip> If the order were the other direction, it would force you to
    Phillip> read right-to-left in order to know what's going to happen to
    Phillip> the function.

    Phillip> So, I vote for left-to-right on the grounds of "readability
    Phillip> counts".  :)

+1.

Skip