access interactive namespace from module (shared namespace?)

[Ulrich Dorda]

I've got a probably embarrassing trivial problem with namespaces, but couldn't solve it 
myself nor find an answer in the net. Hopefully one of you guys can help me.

What I want to do:
Use the interactive shell and e.g define the variable a there.
Then load a module and access a from within.

e.g file "utest.py"

def doit():
	print 2*a

in the shell:

import utest
a=3
utest.doit()  <- I want this to print 2*a, but of course obtain: <type 
exceptions.NameError'>: global name 'a' is not defined

Any change I do to a in the shell should be seen from the doit() function, any variable 
assignment I do in the doit() function should be seen in the shell. I guess it's somehow a 
namespace sharing.

Actually the function doit() will contain an eval() function that should evaluate a (via a 
gui) dynamically inserted expression.

Any one got a clue? (a clue what I try to say and how to help?!)

Thanks a lot in advance!!

Ulrich