Question

I’m trying to write a wrapper for an external module in python. The module provides a method to conjugate a verb that expects 2 arguments. I would like to wrap it into several methods and I was wondering if there was a way to do it programatically.

i.e. instead of:

class X:
  def a(self,arg):
    return module.do(arg,'a')
  def b(self,arg):
    return module.do(arg,'b')
  ...
  def z(self,arg):
    return module.do(arg,'z')

I was trying to do:

class X:
  def a(self,arg):
    return module.do(arg,__name__)
    return module.do(arg,__name__)
  def __init__(self):
    setattr(self,'b',self.a)
    ...
    setattr(self,'z',self.a)
x = X()
x.a(y)
x.b(y)
x.z(y)

The problem is that name returns the top level method, not the current.
I tried both:

from inspect import stack
stack()[0][3]
import sys
sys._getframe().f_code.co_name

But when I call b() or z() I get ‘a’.
Am I doing something wrong? Is there any other way to achieve a similar result?

Answer 1

You’re simply setting all the b to z attributes of your class to point to the a method. This means that whenever somebody accesses instance.b, it gives back the a method (which is why the co_name is always a).

You can accomplish what you want like this:

import string

class X(object):
  def __getattr__(self, name):
    if name in string.lowercase and len(name) == 1:
      def call_into_module(arg):
        return module.do(arg, name)
      return call_into_module

    return super(X, self).__getattr__(name)