namespaces and eval

[Arnaud Delobelle]

dave.g1234 at gmail.com writes:

> Sorry for the repost, didnt' quite finish
>
> Suppose I have a function in module X that calls eval e.g,
>
> X.py
> _______
> Def foo(bar):
>         Eval(bar)
> _______
>
> Now eval will be called using the default eval(bar,globals(),locals())
> and globals will pull in anything in module X.
>
> Now I have module Y that calls bar like so
> Y.py
> ________
> from x import *
> def biz():
>         print "Im a silly example!"
> Foo("biz()")
> _______
>
> Python will complain that it cannot find biz because it's not the X
> module.
>
> My question - is there any way to a) get a listing of active namespaes
> search ALL active namespaces for a particular variable

sys.modules gives you all the live modules.

> b) get the namespace of the caller withing passing it in (here, Y)

sys._getframe(1).f_globals (resp. sys._getframe(1).f_locals) gives you
the caller's globals (resp. locals).

> c) do anything else to get biz without passing
> foo("biz()",locals(),globals()) or hacking biz into the __builtin__
> namespace(don't know if it's even possible, but it defeats the
> purpose of what I'm trying to do) ?

Functions in Python are objects like any other, and can be passed as
parameters.  I.e:

x.py
----------
def foo(bar):
    bar()

>>> from x import foo
>>> def biz(): print "Boo!"
>>> foo(biz)
Boo!
>>>
 

> I realize this is here for a reason, but I'm working on something
> that's kind of a hack already
>
> Thanks
> dave
>
>
> More gratuitous context. Long story I'm trying to write a hack for a
> concise way of adding arbitrary methods to objects for JPA/JQuery like
> chaning eg.
>
> def foo(self):
>     print "foo"
>     return self;
>
> wrap(x).foo().foo().foo().foo() etc....

What about a composition function instead? I.e.

compose(foo, foo, foo, foo)(x)

Here's one that I made earlier:
http://www.marooned.org.uk/~arno/python/compose.html

[snip]

-- 
Arnaud