mirror of https://github.com/python/cpython
Improve Context construction and representation:
* Rename "trap_enablers" to just "traps". * Simplify names of "settraps" and "setflags" to just "traps" and "flags". * Show "capitals" in the context representation * Simplify the Context constructor to match its repr form so that only the set flags and traps need to be listed. * Representation can now be run through eval(). Improve the error message when the Decimal constructor is given a float. The test suite no longer needs a duplicate reset_flags method.
This commit is contained in:
Raymond Hettinger
parent
d9dfe0213f
commit
bf4406971c
|
|
@ -112,7 +112,7 @@ precision, rounding, or trap enablers:
|
|||
>>> from decimal import *
|
||||
>>> getcontext()
|
||||
Context(prec=28, rounding=ROUND_HALF_EVEN, Emin=-999999999, Emax=999999999,
|
||||
setflags=[], settraps=[])
|
||||
capitals=1, flags=[], traps=[])
|
||||
|
||||
>>> getcontext().prec = 7
|
||||
\end{verbatim}
|
||||
|
|
@ -204,10 +204,10 @@ because many of the traps are enabled:
|
|||
>>> myothercontext = Context(prec=60, rounding=ROUND_HALF_DOWN)
|
||||
>>> myothercontext
|
||||
Context(prec=60, rounding=ROUND_HALF_DOWN, Emin=-999999999, Emax=999999999,
|
||||
setflags=[], settraps=[])
|
||||
capitals=1, flags=[], traps=[])
|
||||
>>> ExtendedContext
|
||||
Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999999, Emax=999999999,
|
||||
setflags=[], settraps=[])
|
||||
capitals=1, flags=[], traps=[])
|
||||
>>> setcontext(myothercontext)
|
||||
>>> Decimal(1) / Decimal(7)
|
||||
Decimal("0.142857142857142857142857142857142857142857142857142857142857")
|
||||
|
|
@ -236,21 +236,21 @@ clear the flags before each set of monitored computations by using the
|
|||
Decimal("3.14159292")
|
||||
>>> getcontext()
|
||||
Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999999, Emax=999999999,
|
||||
setflags=['Inexact', 'Rounded'], settraps=[])
|
||||
capitals=1, flags=[Inexact, Rounded], traps=[])
|
||||
\end{verbatim}
|
||||
|
||||
The \var{setflags} entry shows that the rational approximation to
|
||||
The \var{flags} entry shows that the rational approximation to
|
||||
\constant{Pi} was rounded (digits beyond the context precision were thrown
|
||||
away) and that the result is inexact (some of the discarded digits were
|
||||
non-zero).
|
||||
|
||||
Individual traps are set using the dictionary in the \member{trap_enablers}
|
||||
Individual traps are set using the dictionary in the \member{traps}
|
||||
field of a context:
|
||||
|
||||
\begin{verbatim}
|
||||
>>> Decimal(1) / Decimal(0)
|
||||
Decimal("Infinity")
|
||||
>>> getcontext().trap_enablers[DivisionByZero] = 1
|
||||
>>> getcontext().traps[DivisionByZero] = 1
|
||||
>>> Decimal(1) / Decimal(0)
|
||||
|
||||
Traceback (most recent call last):
|
||||
|
|
@ -264,14 +264,14 @@ To turn all the traps on or off all at once, use a loop. Also, the
|
|||
|
||||
\begin{verbatim}
|
||||
>>> getcontext.clear_flags()
|
||||
>>> for sig in getcontext().trap_enablers:
|
||||
... getcontext().trap_enablers[sig] = 1
|
||||
>>> for sig in getcontext().traps:
|
||||
... getcontext().traps[sig] = 1
|
||||
|
||||
>>> getcontext().trap_enablers.update({Rounded:0, Inexact:0, Subnormal:0})
|
||||
>>> getcontext().traps.update({Rounded:0, Inexact:0, Subnormal:0})
|
||||
>>> getcontext()
|
||||
Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999999, Emax=999999999,
|
||||
setflags=[], settraps=['Clamped', 'Underflow', 'InvalidOperation',
|
||||
'DivisionByZero', 'Overflow'])
|
||||
capitals=1, flags=[], traps=[Clamped, Underflow,
|
||||
InvalidOperation, DivisionByZero, Overflow])
|
||||
\end{verbatim}
|
||||
|
||||
Applications typically set the context once at the beginning of a program
|
||||
|
|
@ -489,7 +489,7 @@ In addition, the module provides three pre-made contexts:
|
|||
In addition to the three supplied contexts, new contexts can be created
|
||||
with the \class{Context} constructor.
|
||||
|
||||
\begin{classdesc}{Context}{prec=None, rounding=None, trap_enablers=None,
|
||||
\begin{classdesc}{Context}{prec=None, rounding=None, traps=None,
|
||||
flags=None, Emin=None, Emax=None, capitals=1}
|
||||
Creates a new context. If a field is not specified or is \constant{None},
|
||||
the default values are copied from the \constant{DefaultContext}. If the
|
||||
|
|
@ -508,7 +508,7 @@ with the \class{Context} constructor.
|
|||
\constant{ROUND_HALF_UP} (away from zero), or
|
||||
\constant{ROUND_UP} (away from zero).
|
||||
|
||||
The \var{trap_enablers} and \var{flags} fields are mappings from signals
|
||||
The \var{traps} and \var{flags} fields are mappings from signals
|
||||
to either \constant{0} or \constant{1}.
|
||||
|
||||
The \var{Emin} and \var{Emax} fields are integers specifying the outer
|
||||
|
|
@ -839,7 +839,7 @@ be a race condition with threads calling \function{getcontext()}. For example:
|
|||
# Set applicationwide defaults for all threads about to be launched
|
||||
DefaultContext.prec=12
|
||||
DefaultContext.rounding=ROUND_DOWN
|
||||
DefaultContext.trap_enablers=dict.fromkeys(Signals, 0)
|
||||
DefaultContext.traps=dict.fromkeys(Signals, 0)
|
||||
setcontext(DefaultContext)
|
||||
|
||||
# Now start all of the threads
|
||||
|
|
|
|||
|
|
@ -70,7 +70,7 @@ NaN
|
|||
-Infinity
|
||||
>>> print dig / 0
|
||||
Infinity
|
||||
>>> getcontext().trap_enablers[DivisionByZero] = 1
|
||||
>>> getcontext().traps[DivisionByZero] = 1
|
||||
>>> print dig / 0
|
||||
Traceback (most recent call last):
|
||||
...
|
||||
|
|
@ -78,12 +78,12 @@ Traceback (most recent call last):
|
|||
...
|
||||
DivisionByZero: x / 0
|
||||
>>> c = Context()
|
||||
>>> c.trap_enablers[InvalidOperation] = 0
|
||||
>>> c.traps[InvalidOperation] = 0
|
||||
>>> print c.flags[InvalidOperation]
|
||||
0
|
||||
>>> c.divide(Decimal(0), Decimal(0))
|
||||
Decimal("NaN")
|
||||
>>> c.trap_enablers[InvalidOperation] = 1
|
||||
>>> c.traps[InvalidOperation] = 1
|
||||
>>> print c.flags[InvalidOperation]
|
||||
1
|
||||
>>> c.flags[InvalidOperation] = 0
|
||||
|
|
@ -98,7 +98,7 @@ InvalidOperation: 0 / 0
|
|||
>>> print c.flags[InvalidOperation]
|
||||
1
|
||||
>>> c.flags[InvalidOperation] = 0
|
||||
>>> c.trap_enablers[InvalidOperation] = 0
|
||||
>>> c.traps[InvalidOperation] = 0
|
||||
>>> print c.divide(Decimal(0), Decimal(0))
|
||||
NaN
|
||||
>>> print c.flags[InvalidOperation]
|
||||
|
|
@ -495,7 +495,11 @@ class Decimal(object):
|
|||
self._int = value._int
|
||||
return
|
||||
|
||||
raise TypeError("Can't convert %r" % value)
|
||||
if isinstance(value, float):
|
||||
raise TypeError("Cannot convert float to Decimal. " +
|
||||
"First convert the float to a string")
|
||||
|
||||
raise TypeError("Cannot convert %r" % value)
|
||||
|
||||
def _convert_other(self, other):
|
||||
"""Convert other to Decimal.
|
||||
|
|
@ -2096,7 +2100,7 @@ class Context(object):
|
|||
prec - precision (for use in rounding, division, square roots..)
|
||||
rounding - rounding type. (how you round)
|
||||
_rounding_decision - ALWAYS_ROUND, NEVER_ROUND -- do you round?
|
||||
trap_enablers - If trap_enablers[exception] = 1, then the exception is
|
||||
traps - If traps[exception] = 1, then the exception is
|
||||
raised when it is caused. Otherwise, a value is
|
||||
substituted in.
|
||||
flags - When an exception is caused, flags[exception] is incremented.
|
||||
|
|
@ -2110,13 +2114,15 @@ class Context(object):
|
|||
"""
|
||||
|
||||
def __init__(self, prec=None, rounding=None,
|
||||
trap_enablers=None, flags=None,
|
||||
traps=None, flags=[],
|
||||
_rounding_decision=None,
|
||||
Emin=None, Emax=None,
|
||||
capitals=None, _clamp=0,
|
||||
_ignored_flags=[]):
|
||||
if flags is None:
|
||||
flags = dict.fromkeys(Signals, 0)
|
||||
if not isinstance(flags, dict):
|
||||
flags = dict([(s,s in flags) for s in Signals])
|
||||
if traps is not None and not isinstance(traps, dict):
|
||||
traps = dict([(s,s in traps) for s in Signals])
|
||||
for name, val in locals().items():
|
||||
if val is None:
|
||||
setattr(self, name, copy.copy(getattr(DefaultContext, name)))
|
||||
|
|
@ -2125,11 +2131,11 @@ class Context(object):
|
|||
del self.self
|
||||
|
||||
def __repr__(self):
|
||||
"""Show the current context in readable form, not in a form for eval()."""
|
||||
"""Show the current context."""
|
||||
s = []
|
||||
s.append('Context(prec=%(prec)d, rounding=%(rounding)s, Emin=%(Emin)d, Emax=%(Emax)d' % vars(self))
|
||||
s.append('setflags=%r' % [f.__name__ for f, v in self.flags.items() if v])
|
||||
s.append('settraps=%r' % [t.__name__ for t, v in self.trap_enablers.items() if v])
|
||||
s.append('Context(prec=%(prec)d, rounding=%(rounding)s, Emin=%(Emin)d, Emax=%(Emax)d, capitals=%(capitals)d' % vars(self))
|
||||
s.append('flags=[' + ', '.join([f.__name__ for f, v in self.flags.items() if v]) + ']')
|
||||
s.append('traps=[' + ', '.join([t.__name__ for t, v in self.traps.items() if v]) + ']')
|
||||
return ', '.join(s) + ')'
|
||||
|
||||
def clear_flags(self):
|
||||
|
|
@ -2139,7 +2145,7 @@ class Context(object):
|
|||
|
||||
def copy(self):
|
||||
"""Returns a copy from self."""
|
||||
nc = Context(self.prec, self.rounding, self.trap_enablers, self.flags,
|
||||
nc = Context(self.prec, self.rounding, self.traps, self.flags,
|
||||
self._rounding_decision, self.Emin, self.Emax,
|
||||
self.capitals, self._clamp, self._ignored_flags)
|
||||
return nc
|
||||
|
|
@ -2159,7 +2165,7 @@ class Context(object):
|
|||
return error().handle(self, *args)
|
||||
|
||||
self.flags[error] += 1
|
||||
if not self.trap_enablers[error]:
|
||||
if not self.traps[error]:
|
||||
#The errors define how to handle themselves.
|
||||
return condition().handle(self, *args)
|
||||
|
||||
|
|
@ -2946,13 +2952,10 @@ def _isnan(num):
|
|||
# The default context prototype used by Context()
|
||||
# Is mutable, so than new contexts can have different default values
|
||||
|
||||
_default_traps = dict.fromkeys(Signals, 0)
|
||||
_default_traps.update({DivisionByZero:1, Overflow:1, InvalidOperation:1})
|
||||
|
||||
DefaultContext = Context(
|
||||
prec=28, rounding=ROUND_HALF_EVEN,
|
||||
trap_enablers=_default_traps,
|
||||
flags=None,
|
||||
traps=[DivisionByZero, Overflow, InvalidOperation],
|
||||
flags=[],
|
||||
_rounding_decision=ALWAYS_ROUND,
|
||||
Emax=DEFAULT_MAX_EXPONENT,
|
||||
Emin=DEFAULT_MIN_EXPONENT,
|
||||
|
|
@ -2964,20 +2967,17 @@ DefaultContext = Context(
|
|||
# contexts and be able to reproduce results from other implementations
|
||||
# of the spec.
|
||||
|
||||
_basic_traps = dict.fromkeys(Signals, 1)
|
||||
_basic_traps.update({Inexact:0, Rounded:0, Subnormal:0})
|
||||
|
||||
BasicContext = Context(
|
||||
prec=9, rounding=ROUND_HALF_UP,
|
||||
trap_enablers=_basic_traps,
|
||||
flags=None,
|
||||
traps=[DivisionByZero, Overflow, InvalidOperation, Clamped, Underflow],
|
||||
flags=[],
|
||||
_rounding_decision=ALWAYS_ROUND,
|
||||
)
|
||||
|
||||
ExtendedContext = Context(
|
||||
prec=9, rounding=ROUND_HALF_EVEN,
|
||||
trap_enablers=dict.fromkeys(Signals, 0),
|
||||
flags=None,
|
||||
traps=[],
|
||||
flags=[],
|
||||
_rounding_decision=ALWAYS_ROUND,
|
||||
)
|
||||
|
||||
|
|
|
|||
|
|
@ -38,7 +38,7 @@ import random
|
|||
# Tests are built around these assumed context defaults
|
||||
DefaultContext.prec=9
|
||||
DefaultContext.rounding=ROUND_HALF_EVEN
|
||||
DefaultContext.trap_enablers=dict.fromkeys(Signals, 0)
|
||||
DefaultContext.traps=dict.fromkeys(Signals, 0)
|
||||
setcontext(DefaultContext)
|
||||
|
||||
|
||||
|
|
@ -105,8 +105,8 @@ class DecimalTest(unittest.TestCase):
|
|||
def setUp(self):
|
||||
global dir
|
||||
self.context = Context()
|
||||
for key in DefaultContext.trap_enablers.keys():
|
||||
DefaultContext.trap_enablers[key] = 1
|
||||
for key in DefaultContext.traps.keys():
|
||||
DefaultContext.traps[key] = 1
|
||||
self.ignore_list = ['#']
|
||||
# Basically, a # means return NaN InvalidOperation.
|
||||
# Different from a sNaN in trim
|
||||
|
|
@ -120,8 +120,8 @@ class DecimalTest(unittest.TestCase):
|
|||
def tearDown(self):
|
||||
"""Cleaning up enviroment."""
|
||||
# leaving context in original state
|
||||
for key in DefaultContext.trap_enablers.keys():
|
||||
DefaultContext.trap_enablers[key] = 0
|
||||
for key in DefaultContext.traps.keys():
|
||||
DefaultContext.traps[key] = 0
|
||||
return
|
||||
|
||||
def eval_file(self, file):
|
||||
|
|
@ -205,9 +205,9 @@ class DecimalTest(unittest.TestCase):
|
|||
theirexceptions = [ErrorNames[x.lower()] for x in exceptions]
|
||||
|
||||
for exception in Signals:
|
||||
self.context.trap_enablers[exception] = 1 #Catch these bugs...
|
||||
self.context.traps[exception] = 1 #Catch these bugs...
|
||||
for exception in theirexceptions:
|
||||
self.context.trap_enablers[exception] = 0
|
||||
self.context.traps[exception] = 0
|
||||
for i, val in enumerate(valstemp):
|
||||
if val.count("'") % 2 == 1:
|
||||
quote = 1 - quote
|
||||
|
|
@ -221,7 +221,7 @@ class DecimalTest(unittest.TestCase):
|
|||
if fname in ('to_sci_string', 'to_eng_string'):
|
||||
if EXTENDEDERRORTEST:
|
||||
for error in theirexceptions:
|
||||
self.context.trap_enablers[error] = 1
|
||||
self.context.traps[error] = 1
|
||||
try:
|
||||
funct(self.context.create_decimal(v))
|
||||
except error:
|
||||
|
|
@ -231,7 +231,7 @@ class DecimalTest(unittest.TestCase):
|
|||
(e, s, error))
|
||||
else:
|
||||
self.fail("Did not raise %s in %s" % (error, s))
|
||||
self.context.trap_enablers[error] = 0
|
||||
self.context.traps[error] = 0
|
||||
v = self.context.create_decimal(v)
|
||||
else:
|
||||
v = Decimal(v)
|
||||
|
|
@ -241,7 +241,7 @@ class DecimalTest(unittest.TestCase):
|
|||
|
||||
if EXTENDEDERRORTEST and fname not in ('to_sci_string', 'to_eng_string'):
|
||||
for error in theirexceptions:
|
||||
self.context.trap_enablers[error] = 1
|
||||
self.context.traps[error] = 1
|
||||
try:
|
||||
funct(*vals)
|
||||
except error:
|
||||
|
|
@ -251,7 +251,7 @@ class DecimalTest(unittest.TestCase):
|
|||
(e, s, error))
|
||||
else:
|
||||
self.fail("Did not raise %s in %s" % (error, s))
|
||||
self.context.trap_enablers[error] = 0
|
||||
self.context.traps[error] = 0
|
||||
try:
|
||||
result = str(funct(*vals))
|
||||
if fname == 'same_quantum':
|
||||
|
|
@ -263,7 +263,7 @@ class DecimalTest(unittest.TestCase):
|
|||
raise
|
||||
|
||||
myexceptions = self.getexceptions()
|
||||
self.resetflags()
|
||||
self.context.clear_flags()
|
||||
|
||||
myexceptions.sort()
|
||||
theirexceptions.sort()
|
||||
|
|
@ -282,10 +282,6 @@ class DecimalTest(unittest.TestCase):
|
|||
L.append(exception)
|
||||
return L
|
||||
|
||||
def resetflags(self):
|
||||
for exception in Signals:
|
||||
self.context.flags[exception] = 0
|
||||
|
||||
def change_precision(self, prec):
|
||||
self.context.prec = prec
|
||||
def change_rounding_method(self, rounding):
|
||||
|
|
|
|||
Loading…
Reference in New Issue