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Merged revisions 61404-61407 via svnmerge from 

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r61404 | raymond.hettinger | 2008-03-15 21:02:04 +0100 (Sat, 15 Mar 2008) | 17 lines

  Removed Exact/Inexact after discussion with Yasskin.

  Unlike Scheme where exactness is implemented as taints, the Python
  implementation associated exactness with data types.  This created
  inheritance issues (making an exact subclass of floats would result
  in the subclass having both an explicit Exact registration and an
  inherited Inexact registration).  This was a problem for the
  decimal module which was designed to span both exact and inexact
  arithmetic.  There was also a question of use cases and no examples
  were found where ABCs for exactness could be used to improve code.
  One other issue was having separate tags for both the affirmative
  and negative cases.  This is at odds with the approach taken
  elsewhere in the Python (i.e. we don't have an ABC both Hashable
  and Unhashable).
........
  r61405 | raymond.hettinger | 2008-03-15 21:37:50 +0100 (Sat, 15 Mar 2008) | 1 line

  Zap one more use of Exact/Inexact.
........
  r61406 | neal.norwitz | 2008-03-15 23:03:18 +0100 (Sat, 15 Mar 2008) | 9 lines

  Add a warning for code like:
    assert (0, 'message')

  An empty tuple does not create a warning.  While questionable usage:
    assert (), 'message'

  should not display a warning.  Tested manually.
  The warning message could be improved.  Feel free to update it.
........
  r61407 | neal.norwitz | 2008-03-15 23:36:01 +0100 (Sat, 15 Mar 2008) | 1 line

  Handle memory allocation failure.  Found by Adam Olsen
........
This commit is contained in:
Christian Heimes 2008-03-16 00:32:36 +00:00
parent dd15f6c315
commit 08976cb696
5 changed files with 17 additions and 64 deletions
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2
Lib/decimal.py
View File

@ -504,7 +504,7 @@ def localcontext(ctx=None):
##### Decimal class #######################################################
class Decimal(_numbers.Real, _numbers.Inexact):
class Decimal(_numbers.Real):
"""Floating point class for decimal arithmetic."""
__slots__ = ('_exp','_int','_sign', '_is_special')

59
Lib/numbers.py
View File

@ -7,10 +7,7 @@ TODO: Fill out more detailed documentation on the operators."""
from abc import ABCMeta, abstractmethod, abstractproperty
__all__ = ["Number", "Exact", "Inexact",
"Complex", "Real", "Rational", "Integral",
]
__all__ = ["Number", "Complex", "Real", "Rational", "Integral"]
class Number(metaclass=ABCMeta):
"""All numbers inherit from this class.
@ -20,59 +17,13 @@ class Number(metaclass=ABCMeta):
"""
class Exact(Number):
"""Operations on instances of this type are exact.
As long as the result of a homogenous operation is of the same
type, you can assume that it was computed exactly, and there are
no round-off errors. Laws like commutativity and associativity
hold.
"""
Exact.register(int)
class Inexact(Number):
"""Operations on instances of this type are inexact.
Given X, an instance of Inexact, it is possible that (X + -X) + 3
== 3, but X + (-X + 3) == 0. The exact form this error takes will
vary by type, but it's generally unsafe to compare this type for
equality.
"""
Inexact.register(complex)
Inexact.register(float)
# Inexact.register(decimal.Decimal)
## Notes on Decimal
## ----------------
## Decimal has all of the methods specified by the Real abc, but it should
## not be registered as a Real because decimals do not interoperate with
## binary floats.
##
## Decimal has some of the characteristics of Integrals. It provides
## logical operations but not as operators. The logical operations only apply
## to a subset of decimals (those that are non-negative, have a zero exponent,
## and have digits that are only 0 or 1). It does provide __long__() and
## a three argument form of __pow__ that includes exactness guarantees.
## It does not provide an __index__() method.
##
## Depending on context, decimal operations may be exact or inexact.
##
## When decimal is run in a context with small precision and automatic rounding,
## it is Inexact. See the "Floating point notes" section of the decimal docs
## for an example of losing the associative and distributive properties of
## addition.
##
## When decimal is used for high precision integer arithmetic, it is Exact.
## When the decimal used as fixed-point, it is Exact.
## When it is run with sufficient precision, it is Exact.
## When the decimal.Inexact trap is set, decimal operations are Exact.
## For an example, see the float_to_decimal() recipe in the "Decimal FAQ"
## section of the docs -- it shows an how traps are used in conjunction
## with variable precision to reliably achieve exact results.
## binary floats (i.e. Decimal('3.14') + 2.71828 is undefined). But,
## abstract reals are expected to interoperate (i.e. R1 + R2 should be
## expected to work if R1 and R2 are both Reals).
class Complex(Number):
"""Complex defines the operations that work on the builtin complex type.
@ -308,7 +259,7 @@ class Real(Complex):
Real.register(float)
class Rational(Real, Exact):
class Rational(Real):
""".numerator and .denominator should be in lowest terms."""
@abstractproperty

7
Lib/test/test_abstract_numbers.py
View File

@ -4,7 +4,6 @@ import math
import operator
import unittest
from numbers import Complex, Real, Rational, Integral
from numbers import Exact, Inexact
from numbers import Number
from test import test_support
@ -12,8 +11,6 @@ class TestNumbers(unittest.TestCase):
def test_int(self):
self.failUnless(issubclass(int, Integral))
self.failUnless(issubclass(int, Complex))
self.failUnless(issubclass(int, Exact))
self.failIf(issubclass(int, Inexact))
self.assertEqual(7, int(7).real)
self.assertEqual(0, int(7).imag)
@ -24,8 +21,6 @@ class TestNumbers(unittest.TestCase):
def test_float(self):
self.failIf(issubclass(float, Rational))
self.failUnless(issubclass(float, Real))
self.failIf(issubclass(float, Exact))
self.failUnless(issubclass(float, Inexact))
self.assertEqual(7.3, float(7.3).real)
self.assertEqual(0, float(7.3).imag)
@ -34,8 +29,6 @@ class TestNumbers(unittest.TestCase):
def test_complex(self):
self.failIf(issubclass(complex, Real))
self.failUnless(issubclass(complex, Complex))
self.failIf(issubclass(complex, Exact))
self.failUnless(issubclass(complex, Inexact))
c1, c2 = complex(3, 2), complex(4,1)
# XXX: This is not ideal, but see the comment in math_trunc().

8
Python/compile.c
View File

@ -2223,6 +2223,14 @@ compiler_assert(struct compiler *c, stmt_ty s)
if (assertion_error == NULL)
return 0;
}
if (s->v.Assert.test->kind == Tuple_kind &&
asdl_seq_LEN(s->v.Assert.test->v.Tuple.elts) > 0) {
const char* msg =
"assertion is always true, perhaps remove parentheses?";
if (PyErr_WarnExplicit(PyExc_SyntaxWarning, msg, c->c_filename,
c->u->u_lineno, NULL, NULL) == -1)
return 0;
}
VISIT(c, expr, s->v.Assert.test);
end = compiler_new_block(c);
if (end == NULL)

5
Python/symtable.c
View File

@ -33,8 +33,9 @@ PySTEntry_New(struct symtable *st, identifier name, _Py_block_ty block,
k = PyLong_FromVoidPtr(key);
if (k == NULL)
goto fail;
ste = (PySTEntryObject *)PyObject_New(PySTEntryObject,
&PySTEntry_Type);
ste = PyObject_New(PySTEntryObject, &PySTEntry_Type);
if (ste == NULL)
goto fail;
ste->ste_table = st;
ste->ste_id = k;
ste->ste_tmpname = 0;