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

[Paul Moore]

Skip Montanaro <skip at pobox.com> writes:

>     >> What are the restrictions on list items?
>     >> 
>     >> Only a function?
>     >> Only a code object?  (I assume so)
>     >> Must the code return the original function?
>     >> Must the code return a code object?
>
>     Phillip> Any callable object.  May return anything.
>
> Must take a single argument, which itself must be a callable, right?

I work from the equivalence of

    def f [a, b, c] (args):
        ...

and

    def f(args):
        ...
    f = a(f)
    f = b(f)
    f = c(f)

Hence, all wrappers *will be called with* a single argument. That
argument may not be a callable (if a returns a non-callable, that's
what b will get) and the return value need not be a callable. Such
uses could be considered strange, however...

Paul.
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