[Python-checkins] r60487 - in python/trunk/Lib: rational.py test/test_rational.py

Fri Feb 1 08:05:46 CET 2008

Author: jeffrey.yasskin
Date: Fri Feb 1 08:05:46 2008
New Revision: 60487
Modified:
 python/trunk/Lib/rational.py
 python/trunk/Lib/test/test_rational.py
Log:
Roll back r60248. It's useful to encourage users not to change Rational
instances.
Modified: python/trunk/Lib/rational.py
==============================================================================

--- python/trunk/Lib/rational.py	(original)
+++ python/trunk/Lib/rational.py	Fri Feb 1 08:05:46 2008
@@ -43,7 +43,7 @@
 
 """
 
- __slots__ = ('numerator', 'denominator')
+ __slots__ = ('_numerator', '_denominator')
 
 # We're immutable, so use __new__ not __init__
 def __new__(cls, numerator=0, denominator=1):
@@ -93,8 +93,8 @@
 raise ZeroDivisionError('Rational(%s, 0)' % numerator)
 
 g = gcd(numerator, denominator)
- self.numerator = int(numerator // g)
- self.denominator = int(denominator // g)
+ self._numerator = int(numerator // g)
+ self._denominator = int(denominator // g)
 return self
 
 @classmethod
@@ -168,6 +168,14 @@
 result = new
 return result
 
+ @property
+ def numerator(a):
+ return a._numerator
+
+ @property
+ def denominator(a):
+ return a._denominator
+
 def __repr__(self):
 """repr(self)"""
 return ('Rational(%r,%r)' % (self.numerator, self.denominator))
Modified: python/trunk/Lib/test/test_rational.py
==============================================================================
--- python/trunk/Lib/test/test_rational.py	(original)
+++ python/trunk/Lib/test/test_rational.py	Fri Feb 1 08:05:46 2008
@@ -119,6 +119,17 @@
 r.__init__(2, 15)
 self.assertEquals((7, 3), _components(r))
 
+ self.assertRaises(AttributeError, setattr, r, 'numerator', 12)
+ self.assertRaises(AttributeError, setattr, r, 'denominator', 6)
+ self.assertEquals((7, 3), _components(r))
+
+ # But if you _really_ need to:
+ r._numerator = 4
+ r._denominator = 2
+ self.assertEquals((4, 2), _components(r))
+ # Which breaks some important operations:
+ self.assertNotEquals(R(4, 2), r)
+
 def testFromFloat(self):
 self.assertRaisesMessage(
 TypeError, "Rational.from_float() only takes floats, not 3 (int)",
