Created
October 26, 2010 09:09
-
-
Save zerko/646574 to your computer and use it in GitHub Desktop.
for habr
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import unittest | |
import logging | |
logging.basicConfig(level = logging.DEBUG) | |
log = logging.getLogger("messaged.expression") | |
class MessagedExpression(object): | |
def __init__(self, val, msg): | |
self.msg = msg | |
self.val = val | |
self.bool = None | |
def __nonzero__(self): | |
return self.__bool__() | |
def __bool__(self): | |
if self.bool is not None: | |
return self.bool | |
if callable(self.val): | |
log.debug("%s evaluated" % self.val) | |
self.val = self.val() | |
return bool(self.val) | |
def __and__(self, other): | |
if bool(self) == False: | |
return self | |
self.bool = bool(other) | |
self.msg = other.msg | |
return self | |
def __or__(self, other): | |
if bool(self) == True: | |
return self | |
else: | |
if not bool(other): | |
if self.msg.__class__ is not list: | |
self.msg = [self.msg,] | |
self.msg.append(other.msg) | |
self.bool = bool(other) | |
return self | |
_me = MessagedExpression | |
def calculate_me(): | |
log.debug("hardcore calculations") | |
class Test(unittest.TestCase): | |
def test(self): | |
result = _me("123","first") & _me(False, "second") & _me(calculate_me,"calculated") | |
self.assertEqual(result.msg,"second") | |
result = _me("123","first") & _me(False, "second") | _me(calculate_me,"calculated") | |
self.assertEqual(result.msg,["second","calculated"]) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment