Python function composition with a dot operator

composable.py

class Composable(object):
  ''' A function decorator that allows you to use Haskell style dot notation for function composition '''
    fns = {}

    def __init__(self, fn):
        self.fn = fn
        Composable.fns[fn.__name__] = fn

    def __call__(self, *args, **kwargs):
      ''' simply calls the function '''
        return self.fn(*args, **kwargs)

    def __getattr__(self, other):
      ''' The returned function will only be able to be on the left of a composition, for now '''
        return Composable(compose(self.fn, self.fns[other]))

# Examples:
@Composable
def add_17(x):
    return x + 17
    
@Composable
def subtract_7(x):
    return x - 17
    
add_17 . subtract_7 (10) == 20  # True
Composable(lambda x: x * 2) . add_17 . add_17 . subtract_7 == 54  # True

# Limitations
# - Anonymous functions can only be on the left hand side of a composition (because they don't have names)

# Ideas:
# - Get the module name and scope when creating a Composable
#   - This will allow you to have a function with the same name from two different modules
#   - It will also allow you to lookup unknown functions in the module it is being called from