Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

Work through several open todos: 

* Added test for pickling contexts
* Renamed ExceptionList to Signals (to match wording in the spec)
* Simplified Context constructor by allowing flags=None to automatically
  generate a zeroed-out flags dictionary.
* inlined _convertString() which was used only once
* _rounding_decision is private, so excluded its contants from __all__.
* added an XXX comment with concerns about subclassing signals results in
  a deviation from the spec (maybe important, maybe not).
* Taught the test_suite to determine its own directory (modeled after code
  in regrtest.py).  Enables it to be run when the current directory is not
  the test directory.
* Added a clear_flags() method to the Context API to make it easier to do
  a common operation with flags.
* Fixed the trap_enablers defaults in BasicDefaultContext to match the spec.
This commit is contained in:
Raymond Hettinger 2004-07-03 10:02:28 +00:00
parent 41d13f61d2
commit d9c0a7ae94
2 changed files with 55 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
Lib/decimal.py
View File

@ -9,13 +9,8 @@
# Todo:
# Add deepcopy and pickle support for contexts
# Consider having a SimpleDecimal subclass implementing X3.274 semantics
# Improve the Context API
# Especially with respect to setting flags and traps
# Consider adding a clear_flags() method to Context
# Provide a clean way of attaching monetary format representations
# Review all exposed constants for utility vs. namespace clutter
# Make tests independent of DefaultContext.prec == 9
"""
@ -139,8 +134,7 @@ __all__ = [
# Constants for use in setting up contexts
'ROUND_DOWN', 'ROUND_HALF_UP', 'ROUND_HALF_EVEN', 'ROUND_CEILING',
'ROUND_FLOOR', 'ROUND_UP', 'ROUND_HALF_DOWN',
'NEVER_ROUND', 'ALWAYS_ROUND',
'ExceptionList', # <-- Used for building trap/flag dictionaries
'Signals', # <-- Used for building trap/flag dictionaries
# Functions for manipulating contexts
'setcontext', 'getcontext',
@ -244,6 +238,12 @@ class InvalidOperation(DecimalException):
return Decimal( (args[1]._sign, args[1]._int, 'n') )
return NaN
# XXX Is there a logic error in subclassing InvalidOperation?
# Setting the InvalidOperation trap to zero does not preclude ConversionSyntax.
# Also, incrementing Conversion syntax flag will not increment InvalidOperation.
# Both of these issues interfere with cross-language portability because
# code following the spec would not know about the Python subclasses.
class ConversionSyntax(InvalidOperation):
"""Trying to convert badly formed string.
@ -410,8 +410,8 @@ def _filterfunc(obj):
except TypeError:
return False
#ExceptionList holds the exceptions
ExceptionList = filter(_filterfunc, globals().values())
#Signals holds the exceptions
Signals = filter(_filterfunc, globals().values())
del _filterfunc
@ -492,7 +492,10 @@ class Decimal(object):
self._sign = sign
self._int = tuple(map(int, diag)) #Diagnostic info
return
self._convertString(value, context)
try:
self._sign, self._int, self._exp = _string2exact(value)
except ValueError:
self._sign, self._int, self._exp = context._raise_error(ConversionSyntax)
return
# tuple/list conversion (possibly from as_tuple())
@ -594,19 +597,6 @@ class Decimal(object):
return other
return 0
def _convertString(self, value, context=None):
"""Changes self's value to that in a string.
A bad string causes a ConversionSyntax error.
"""
if context is None:
context = getcontext()
try:
self._sign, self._int, self._exp = _string2exact(value)
except ValueError:
self._sign, self._int, self._exp = context._raise_error(ConversionSyntax)
return
def __nonzero__(self):
"""Is the number non-zero?
@ -1433,8 +1423,6 @@ class Decimal(object):
def __int__(self):
"""Converts self to a int, truncating if necessary."""
# XXX This should be implemented in terms of tested
# functions in the standard
if self._isnan():
context = getcontext()
return context._raise_error(InvalidContext)
@ -2115,6 +2103,8 @@ class Decimal(object):
return self # My components are also immutable
return self.__class__(str(self))
##### Context class ###########################################
# get rounding method function:
rounding_functions = [name for name in Decimal.__dict__.keys() if name.startswith('_round_')]
@ -2152,6 +2142,8 @@ class Context(object):
Emin=DEFAULT_MIN_EXPONENT, Emax=DEFAULT_MAX_EXPONENT,
capitals=1, _clamp=0,
_ignored_flags=[]):
if flags is None:
flags = dict.fromkeys(Signals, 0)
DefaultLock.acquire()
for name, val in locals().items():
if val is None:
@ -2161,13 +2153,17 @@ class Context(object):
DefaultLock.release()
del self.self
def clear_flags(self):
"""Reset all flags to zero"""
for flag in self.flags:
self.flag = 0
def copy(self):
"""Returns a copy from self."""
nc = Context(self.prec, self.rounding, self.trap_enablers, self.flags,
self._rounding_decision, self.Emin, self.Emax,
self.capitals, self._clamp, self._ignored_flags)
return nc
__copy__ = copy
def _raise_error(self, error, explanation = None, *args):
"""Handles an error
@ -2192,7 +2188,7 @@ class Context(object):
def _ignore_all_flags(self):
"""Ignore all flags, if they are raised"""
return self._ignore_flags(*ExceptionList)
return self._ignore_flags(*Signals)
def _ignore_flags(self, *flags):
"""Ignore the flags, if they are raised"""
@ -2959,20 +2955,16 @@ def isnan(num):
##### Setup Specific Contexts ################################
def _zero_exceptions():
"Helper function mapping all exceptions to zero."
d = {}
for exception in ExceptionList:
d[exception] = 0
return d
_basic_traps = dict.fromkeys(Signals, 1)
_basic_traps.update({Inexact:0, Rounded:0, Subnormal:0})
# The default context prototype used by Context()
# Is mutable, so than new contexts can have different default values
DefaultContext = Context(
prec=SINGLE_PRECISION, rounding=ROUND_HALF_EVEN,
trap_enablers=_zero_exceptions(),
flags=_zero_exceptions(),
trap_enablers=dict.fromkeys(Signals, 0),
flags=None,
_rounding_decision=ALWAYS_ROUND,
)
@ -2981,25 +2973,22 @@ DefaultContext = Context(
# contexts and be able to reproduce results from other implementations
# of the spec.
_basic_traps = _zero_exceptions()
_basic_traps.update({Inexact:1, Rounded:1, Subnormal:1})
BasicDefaultContext = Context(
prec=9, rounding=ROUND_HALF_UP,
trap_enablers=_basic_traps,
flags=_zero_exceptions(),
flags=None,
_rounding_decision=ALWAYS_ROUND,
)
ExtendedDefaultContext = Context(
prec=SINGLE_PRECISION, rounding=ROUND_HALF_EVEN,
trap_enablers=_zero_exceptions(),
flags=_zero_exceptions(),
trap_enablers=dict.fromkeys(Signals, 0),
flags=None,
_rounding_decision=ALWAYS_ROUND,
)
##### Useful Constants (internal use only######################
##### Useful Constants (internal use only) ####################
#Reusable defaults
Inf = Decimal('Inf')

30
Lib/test/test_decimal.py
View File

@ -35,7 +35,12 @@ from test.test_support import TestSkipped, run_unittest, run_doctest, is_resourc
import threading
TESTDATADIR = 'decimaltestdata'
dir = os.curdir + os.sep + TESTDATADIR + os.sep
if __name__ == '__main__':
file = sys.argv[0]
else:
file = __file__
testdir = os.path.dirname(file) or os.curdir
dir = testdir + os.sep + TESTDATADIR + os.sep
skip_expected = not os.path.isdir(dir)
@ -190,7 +195,7 @@ class DecimalTest(unittest.TestCase):
quote = 0
theirexceptions = [ErrorNames[x.lower()] for x in exceptions]
for exception in ExceptionList:
for exception in Signals:
self.context.trap_enablers[exception] = 1 #Catch these bugs...
for exception in theirexceptions:
self.context.trap_enablers[exception] = 0
@ -212,7 +217,7 @@ class DecimalTest(unittest.TestCase):
funct(self.context.create_decimal(v))
except error:
pass
except ExceptionList, e:
except Signals, e:
self.fail("Raised %s in %s when %s disabled" % \
(e, s, error))
else:
@ -232,7 +237,7 @@ class DecimalTest(unittest.TestCase):
funct(*vals)
except error:
pass
except ExceptionList, e:
except Signals, e:
self.fail("Raised %s in %s when %s disabled" % \
(e, s, error))
else:
@ -242,7 +247,7 @@ class DecimalTest(unittest.TestCase):
result = str(funct(*vals))
if fname == 'same_quantum':
result = str(int(eval(result))) # 'True', 'False' -> '1', '0'
except ExceptionList, error:
except Signals, error:
self.fail("Raised %s in %s" % (error, s))
except: #Catch any error long enough to state the test case.
print "ERROR:", s
@ -263,13 +268,13 @@ class DecimalTest(unittest.TestCase):
def getexceptions(self):
L = []
for exception in ExceptionList:
for exception in Signals:
if self.context.flags[exception]:
L.append(exception)
return L
def resetflags(self):
for exception in ExceptionList:
for exception in Signals:
self.context.flags[exception] = 0
def change_precision(self, prec):
@ -1046,6 +1051,16 @@ class DecimalPythonAPItests(unittest.TestCase):
e = pickle.loads(p)
self.assertEqual(d, e)
class ContextAPItests(unittest.TestCase):
def test_pickle(self):
c = Context()
e = pickle.loads(pickle.dumps(c))
for k in vars(c):
v1 = vars(c)[k]
v2 = vars(e)[k]
self.assertEqual(v1, v2)
def test_main(arith=False, verbose=None):
""" Execute the tests.
@ -1059,6 +1074,7 @@ def test_main(arith=False, verbose=None):
DecimalUseOfContextTest,
DecimalUsabilityTest,
DecimalPythonAPItests,
ContextAPItests,
]
if arith or is_resource_enabled('decimal'):