[New-bugs-announce] [issue23201] Decimal(0)**0 is an error, 0**0 is 1, but Decimal(0) == 0

[Devin Jeanpierre]

New submission from Devin Jeanpierre:

>>> import decimal
>>> x = 0
>>> y = float(x)
>>> z = decimal.Decimal(x)
>>> x == y == z == x
True
>>> x ** x
1
>>> y**y
1.0
>>> z**z
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/decimal.py", line 2216, in __pow__
    return context._raise_error(InvalidOperation, '0 ** 0')
  File "/usr/lib/python2.7/decimal.py", line 3872, in _raise_error
    raise error(explanation)
decimal.InvalidOperation: 0 ** 0

This is PHP-like and confusing, and maybe not justified just by standards compliance. If it is justified by standards compliance, this deserves to be spelled out in big red letters in the documentation for the decimal module, along with any other inconsistencies.

----------
components: Library (Lib)
messages: 233711
nosy: Devin Jeanpierre
priority: normal
severity: normal
status: open
title: Decimal(0)**0 is an error, 0**0 is 1, but Decimal(0) == 0
versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4, Python 3.5, Python 3.6

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue23201>
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