if/elif chain with assignment expressions

[Paul Rubin]

"Neil Hodgson" <nhodgson at bigpond.net.au> writes:
> Pruning the possible cause tree is extremely valuable and Python
> cooperates with a well thought out set of restrictions.

If you're trying to add restrictions to prune a cause tree, how about
starting with private instance variables in classes and modules
instead of the silly underscore name mangling hack.  Maybe you can
also do something about scoping madness:

    def f():
        p = 3
        def g():
            p = 4
            print 'g',p
        g()
        print 'f',p

    f()

There's no way in g to set f's variable called 'p', which defeats the
purpose of nested functions as generally used since the days of Algol-60.

> Being able to depend on the absence of assignments in if and while
> statements is a benefit when fixing Python code over C/C++.

Not if it makes the code more complicated and bug-prone.