[Python-Dev] Re: Deprecating locals() (was Re: nested scopes and global: some corner cases)

[Ka-Ping Yee]

On Sun, 11 Mar 2001, Tim Peters wrote:
> OK by me.  Note that we agreed long ago that if nested scopes ever made it
> in, we would need to supply a way to get a "namespace mapping" object so that
> stuff like:
> 
>     print "The value of i is %(i)s and j %(j)s" % locals()
> 
> could be replaced by:
> 
>     print "The value of i is %(i)s and j %(j)s" % namespace_map_object()

I remarked to Jeremy at Python 9 that, given that we have new
variable lookup rules, there should be an API to perform this
lookup.  I suggested that a new method on frame objects would
be a good idea, and Jeremy & Barry seemed to agree.

I was originally thinking of frame.lookup('whatever'), but if
that method happens to be tp_getitem, then i suppose

    print "i is %(i)s and j is %(j)s" % sys.getframe()

would work.  We could call it something else, but one way or
another it's clear to me that this object has to follow lookup
rules that are completely consistent with whatever kind of
scoping is in effect (i.e. throw out *both* globals() and
locals() and provide one function that looks up the whole set
of visible names, rather than just one scope's contents).


-- ?!ng

"Computers are useless.  They can only give you answers."
    -- Pablo Picasso