New submission from Mark Dickinson <dicki...@gmail.com>:
http://speleotrove.com/decimal/daexcep.html specifies a precedence for decimal
exceptional conditions (scroll right to the bottom of the page):
"""The Clamped, Inexact, Rounded, and Subnormal conditions can coincide with
each other or with other conditions. In these cases then any trap enabled for
another condition takes precedence over (is handled before) all of these, any
Subnormal trap takes precedence over Inexact, any Inexact trap takes precedence
over Rounded, and any Rounded trap takes precedence over Clamped."""
Currently the decimal module doesn't follow this. For example, the following
should raise decimal.Overflow, not decimal.Inexact:
Python 3.2a0 (py3k:80609, Apr 29 2010, 11:46:22)
[GCC 4.2.1 (SUSE Linux)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from decimal import *
>>> getcontext().traps[Inexact] = True
>>> Decimal('1e100').exp()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/dickinsm/Source/py3k/Lib/decimal.py", line 3002, in exp
ans = ans._fix(context)
File "/home/dickinsm/Source/py3k/Lib/decimal.py", line 1658, in _fix
context._raise_error(Inexact)
File "/home/dickinsm/Source/py3k/Lib/decimal.py", line 3866, in _raise_error
raise error(explanation)
decimal.Inexact: None
It's also not clear to me exactly which flags should be set in a case like this.
----------
assignee: mark.dickinson
messages: 104484
nosy: mark.dickinson
priority: normal
severity: normal
status: open
title: decimal module doesn't respect precedence rules for exceptional
conditions
type: behavior
versions: Python 2.6, Python 2.7, Python 3.1, Python 3.2
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue8567>
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