Circular refs

[Tim Peters]

[Tim]
> The prime thing that killed adopting lexical closures was the cyclic
> trash problem then, and Greg Ewing just bumped into that again
> recently in his implementation.

[Greg Himself]
> Er, my implementation is actually a *solution* to the
> cyclic trash problem.

1. That's nice.

2. "The cyclic trash problem" isn't limited to lexical closures.

3. At

    http://www.cosc.canterbury.ac.nz/~greg/python/lexscope.html

I read (& still do <wink>):

    It is still possible to create cycles if you're not careful. For
    instance, storing a local function or the value of a lambda
    expression in a local variable of a scope enclosing its definition
    will create a cycle.

That's precisely the flavor of cycle that killed lexical closures 3 years
ago, as that's precisely the kind of thing the Scheme camp wants to do
routinely; avoiding cycles in closures with (merely) dynamic extent isn't a
problem for you now, and wasn't a problem for Guido then.

those-who-don't-remember-history-are-doomed-to-be-beat-over-the-
    head-with-it<wink>-ly y'rs  - tim