suggestions for functional style (singleton pattern?)

[Ian Kelly]

On Mon, Mar 2, 2015 at 8:59 AM, Michael Torrie <torriem at gmail.com> wrote:
> Now I don't know of any way of implementing class-style properties on a
> module as you can do in a class, but if that were needed you would write
> a standard class and instantiate a singleton inside the module itself
> perhaps.

This works, although I'm not sure that I would do it in real code.

>>> class PropertyModule(types.ModuleType):
...     @property
...     def parrot(self):
...         return "Norwegian Blue"
...
>>> sys.modules['parrot_sketch'] = PropertyModule('parrot_sketch')
>>> import parrot_sketch
>>> parrot_sketch.parrot
'Norwegian Blue'

Note that if the user does "from parrot_sketch import parrot", then
the property is evaluated at import time and any changes won't be
reflected in the local binding, which might cause some surprises.

Also, this isn't really a singleton any longer since the user might
just create another instance of the class, but you can hide the class
and present just the module as the API.