What does Python fix?

[Jason Orendorff]

David Eppstein wrote:
> Tim Peters wrote:
> > This is what Smalltalk was striving for, but it failed to achieve a key
> > insight:  nameless code blocks are easier to reuse if they're 
> > named <wink>.
> 
> But (unlike the unnamed lambda-forms) named code blocks are unable to 
> access the local variables of some other code block.

I can't be 100% sure this is what you're referring to here,
but if you mean this sort of thing:

def cube_root(x):
    """ Exercise 1.8 from SICP (Abelson and Sussman) """

    def square(n):
        return n * n

    def cube(n):
        return n * n * n

    def good_enough(guess):
        # NOTE reference to outer variable x
        # and outer local function cube
        return -0.000001 < cube(guess) - x < 0.000001

    def improve_guess(y):
        # NOTE reference to outer variable x
        # and outer local function square
        return (x / square(y) + 2 * y) / 3

    guess = 1.0
    while not good_enough(guess):
        guess = improve_guess(guess)
    return guess

It works in Python 2.2.

Also works in Python 2.1 if you add "from __future__ import nested_scopes".

## Jason Orendorff    http://www.jorendorff.com/