from types import ModuleType, FunctionType
from collections import ChainMap
class _NSChainedDict(ChainMap, dict):
pass
class Namespace(type):
def __new__(meta, name, bases, dict):
mod = ModuleType(name, dict.get("__doc__"))
for key, obj in dict.items():
if isinstance(obj, FunctionType):
obj = meta.chained_function(meta, obj, mod)
mod.__dict__[key] = obj
return mod
def chained_function(meta, func, mod):
d = _NSChainedDict(mod.__dict__, func.__globals__)
newfunc = FunctionType(func.__code__, d)
newfunc.__doc__ = func.__doc__
newfunc.__defaults__ = func.__defaults__
newfunc.__kwdefaults__ = func.__kwdefaults__
return newfunc
# === Test code ===
a = 999
b = 4
def spam(n=None):
raise RuntimeError('no spam for you!')
class meals(metaclass=Namespace):
a = 2
def repeat(word, count):
return ' '.join([word]*count)
def ham(n=1):
return repeat('ham', n)
def spam(n=3):
return repeat('spam', n)
def breakfast():
"""Return yummy and nutritious breakfast"""
template = "%s with a fried egg on toast and %s"
return template % (spam(), spam(1))
def lunch():
"""Return delicious and healthy lunch"""
template = "cheese, tomato and %s sandwiches"
return template % spam(a)
def dinner():
"""Return tasty and wholesome dinner"""
template = "roast %s garnished with %s"
return template % (ham(), spam(b))
assert meals.breakfast() == 'spam spam spam with a fried egg on toast and spam'
assert meals.lunch() == 'cheese, tomato and spam spam sandwiches'
assert meals.dinner() == 'roast ham garnished with spam spam spam spam'
