Python 2 namespace change? (was Re: [Python-Dev] Changing existing class instances)

[Jim Fulton]

Guido van Rossum wrote:
> 
> > I've suggested this to Guido in the past.  His
> > reasonable response is that this would be too big a
> > change for Python 1. Maybe this is something to consider
> > for Python 2?
> 
> Note: from now on the new name for Python 2 is Python 3000. :-)

I like it. 

> > The basic idea (borrowed from Smalltalk) is to have a kind
> > of dictionary that is a collection of "association"
> > objects.  An association object is simply a pairing of a
> > name with a value. Association objects can be shared among
> > multiple namespaces.
> 
> I've never liked this very much, mostly because it breaks simplicity:
> the idea that a namespace is a mapping from names to values
> (e.g. {"limit": 100, "doit": <function...>, ...}) is beautifully
> simple, while the idea of inserting an extra level of indirection, no
> matter how powerful, is much murkier.

How so? It doesn't change the mapping semantics.
 
> There's also the huge change in semantics, as you point out;
> currently,
> 
>         from foo import bar
> 
> has the same effect (on bar anyway) as
> 
>         import foo
>         bar = foo.bar           # i.e. copying an object reference
>         del foo
> 
> while under your proposal it would be more akin to changing all
> references to bar to become references to foo.bar.
> 
> Of course that's what the moral equivalent of "from ... import ..."
> does in most other languages anyway, so we might consider this for
> Python 3000;

Cool. Again, it would also make function global variable access
faster and cleaner in some ways.

> however it would break a considerable amount of old code,
> I think. 

Really? I wonder. I bet it would break alot less old
code that other recent changes.

> (Not to mention brain

It makes my brain feel much better. :)

> and book breakage. :-)

Hey, all of the books will have to be rewritten for Python 3000.

Jim

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