[Python-ideas] Re: CPP Namespaces For Python

Oct. 7, 2020

      I have no idea if this is a good idea, but Python already has modules to be
namespaces for a collection of functions and values.

And while a class decorator is *supposed* to return a class, it can, in
fact, return anything. So you can make a decorator that converts a class
definition to a module object:

In [47]: def make_mod(cls):
    ...:     mod = imp.new_module(cls.__name__)
    ...:     for name, attr in vars(cls).items():
    ...:         if not name.startswith("_"):
    ...:             setattr(mod, name, attr)
    ...:     return mod
    ...:

In [48]: @make_mod
    ...: class Fake:
    ...:     an_attribute = "this"
    ...:     def a_function(a,b):
    ...:         print("a_function:", a, b)
    ...:

In [49]: Fake.an_attribute
Out[49]: 'this'

In [50]: Fake.a_function(3, 4)
a_function: 3 4

In [51]: type(Fake)
Out[51]: module

In [52]: vars(Fake)
Out[52]:
{'__name__': 'Fake',
 '__doc__': None,
 '__package__': None,
 '__loader__': None,
 '__spec__': None,
 'an_attribute': 'this',
 'a_function': <function __main__.Fake.a_function(a, b)>}

I expect this will give your functions a very odd globals()  though ;-)

But this made me think -- we already have modules, so if we do want a
"namespace" type of some sort, why not simply have syntax for making a
module inline:

new_module:
    def this():
        pass
    x = 4

It would be kind of nice to be able to make anew module without having to
have an actual file (or fake one)

-CHB

-CHB

On Tue, Oct 6, 2020 at 11:02 PM Greg Ewing <greg.ewing@canterbury.ac.nz>
wrote:
...
On 7/10/20 2:45 pm, Random832 wrote:
...
I think the feature should allow for the functions to directly access
each other from the namespace's scope without requiring an attribute
lookup.
That got me thinking, and I came up with this:
def submodule(f):
   return type(f.__name__, (), f())
@submodule
def Stuff():
def f1():
     print("First function")
     f2()
def f2():
     print("Second function")
return locals()
Stuff.f1()
The only ugly part is the need for the 'return locals()', but that could
probably be alleviated with a bit of bytecode hacking.
--
Greg
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