[Python-Dev] Scoping vs augmented assignment vs sets (Re: 'fast locals' in Python 2.5)

[Boris Borcic]

Josiah Carlson wrote:

> The closure/class example is merely a method of encapsulating state,
> which I find easier to define, describe, and document than the closure
> version.

In the case of the code discussed, eg the actual model of

def solve(problem) :
     freebits = set(range(N))
     def search(data) :
         ....
         freebits ^= swap
     ...
     search(initial_data)
     ...

the closure isn't used to encapsulate state if what you mean is passing "search" 
around as an interface to said state - search() is only for internal consumption 
and in fact exists only because of a quite opposite reason. Namely, the search 
requires copying parts of the state and this is most easily expressed with a 
recursive "search" inner function whose parameters are the copied parts.

Whatever you say, it doesn't feel adequate to me nor particularly clear to reify 
such a recursive inner abstraction as an object method. Especially in Python, I 
can't help reading the methods of a class declaration as intended primarily to 
define an external interface, which is misleading in this case.

I'd say a first step in convincing me I am wrong would be to show me examples of 
object methods of the standard library that are recursive, and cut out for 
recursion.

Regards,

Boris Borcic
--
"On naît tous les mètres du même monde"