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# -*- coding: utf-8 -*-
# © 2016 Thomas Binsfeld
# © 2016 ACSONE SA/NV (<http://acsone.eu>)
# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
"""
Provides the AccountingNone singleton.
AccountingNone is a null value that dissolves in basic arithmetic operations,
as illustrated in the examples below. In comparisons, AccountingNone behaves
the same as zero.
>>> 1 + 1
2
>>> 1 + AccountingNone
1
>>> AccountingNone + 1
1
>>> AccountingNone + None
AccountingNone
>>> +AccountingNone
AccountingNone
>>> -AccountingNone
AccountingNone
>>> -(AccountingNone)
AccountingNone
>>> AccountingNone - 1
-1
>>> 1 - AccountingNone
1
>>> abs(AccountingNone)
AccountingNone
>>> AccountingNone - None
AccountingNone
>>> AccountingNone / 2
0.0
>>> 2 / AccountingNone
Traceback (most recent call last):
...
ZeroDivisionError
>>> AccountingNone / AccountingNone
AccountingNone
>>> AccountingNone // 2
0.0
>>> 2 // AccountingNone
Traceback (most recent call last):
...
ZeroDivisionError
>>> AccountingNone // AccountingNone
AccountingNone
>>> AccountingNone * 2
0.0
>>> 2 * AccountingNone
0.0
>>> AccountingNone * AccountingNone
AccountingNone
>>> AccountingNone * None
AccountingNone
>>> None * AccountingNone
AccountingNone
>>> str(AccountingNone)
''
>>> bool(AccountingNone)
False
>>> AccountingNone > 0
False
>>> AccountingNone < 0
False
>>> AccountingNone < 1
True
>>> AccountingNone > 1
False
>>> 0 < AccountingNone
False
>>> 0 > AccountingNone
False
>>> 1 < AccountingNone
False
>>> 1 > AccountingNone
True
>>> AccountingNone == 0
True
>>> AccountingNone == 0.0
True
>>> AccountingNone == None
True
"""
__all__ = ['AccountingNone']
class AccountingNoneType(object):
def __add__(self, other):
if other is None:
return AccountingNone
return other
__radd__ = __add__
def __sub__(self, other):
if other is None:
return AccountingNone
return -other
def __rsub__(self, other):
if other is None:
return AccountingNone
return other
def __iadd__(self, other):
if other is None:
return AccountingNone
return other
def __isub__(self, other):
if other is None:
return AccountingNone
return -other
def __abs__(self):
return self
def __pos__(self):
return self
def __neg__(self):
return self
def __div__(self, other):
if other is AccountingNone:
return AccountingNone
return 0.0
def __rdiv__(self, other):
raise ZeroDivisionError
def __floordiv__(self, other):
if other is AccountingNone:
return AccountingNone
return 0.0
def __rfloordiv__(self, other):
raise ZeroDivisionError
def __truediv__(self, other):
if other is AccountingNone:
return AccountingNone
return 0.0
def __rtruediv__(self, other):
raise ZeroDivisionError
def __mul__(self, other):
if other is None or other is AccountingNone:
return AccountingNone
return 0.0
__rmul__ = __mul__
def __repr__(self):
return 'AccountingNone'
def __str__(self):
return ''
def __nonzero__(self):
return False
def __bool__(self):
return False
def __eq__(self, other):
return other == 0 or other is None or other is AccountingNone
def __lt__(self, other):
return 0 < other
def __gt__(self, other):
return 0 > other
AccountingNone = AccountingNoneType()
if __name__ == '__main__':
import doctest
doctest.testmod()