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A monkeypatching library for python

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zodiac - unite monkey and snake
=================================

**note: this was just an experiment, and is (obviously) abandoned.**

zodiac makes monkeypatching really easy in python. It lets you weave parts of the original module with a patch module that you write. It was written for python 3, but also works in 2.7.

what?
----

let's say you are monkeypatching [socket][]. You can write a patch module, `mysocket.py`:

import socket as _real

class socket(_real.socket):
		def __init__(self, *args, **kwargs):
			print("passthrough!")
			super().__init__()

def something_new():
		print("new function")

This lets you create a patched module based on the original module, with only the parts you want overridden.

>>> from zodiac import build_patch
	>>> mysocket = build_patch('socket', 'mysocket')
	>>>	s = mysocket.socket()
	passthrough!
	>>> s
	<mysocket.socket object, fd=3, family=2, type=1, proto=0>

Other parts of the original module will also use your patch!

>>> conn = mysocket.create_connection(('python.org', 9599))
	passthrough!

Patching globally is simple.

>>> from zodiac import monkeypatch
	>>> monkeypatch('socket', 'mysocket')
	>>> import socket
	>>> s = socket.socket()
	passthrough!
	>>> socket.something_new()
	new function

Check out the tests for more examples.

why is this different?
----------------------

If you were to try monkeypatching without zodiac, you might do something like this:

import socket as _real
	create_connection = _real.create_connection #and so on

class socket(_real.socket):
		def __init__(self, *args, **kwargs):
			print("passthrough!")
			super().__init__()

But this breaks, because `create_connection` uses the socket class that was around when it was defined, and not ours:

>>> import mysocket as socket
	>>> conn = mysocket.create_connection(('python.org', 9599))
	>>> #hrm, no passthrough?

The solution (if you're not using zodiac) is to copy `create_connection` code wholesale from the system module. By redefining it, it uses our socket:

import socket as _real

class socket(_real.socket):
		def __init__(self, *args, **kwargs):
			print("passthrough!")
			super().__init__()

def create_connection(...):
		#copy pasta of python socket.create_connection code

This works, but has obvious problems. You're tied to the original code, and maintaining between different versions of system code is a nightmare.

zodiac "rebases" those functions into the namespace of the new module, which is populated with whatever you overrode in your patch. So your patches can be clean and concise.

installation
------------

zodiac requires python 2.7 or higher. Clone, cd into the directory, and then

python setup.py install

[socket]: http://docs.python.org/py3k/library/socket.html

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