Fixed #12390 -- `Distance` and `Area` objects now support multiplication when they are the right-hand side.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11898 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/measure.py

@@ -27,7 +27,7 @@
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 """
-Distance and Area objects to allow for sensible and convienient calculation 
+Distance and Area objects to allow for sensible and convienient calculation
 and conversions.
 
 Authors: Robert Coup, Justin Bronn
@@ -70,7 +70,7 @@ class MeasureBase(object):
     @classmethod
     def unit_attname(cls, unit_str):
         """
-        Retrieves the unit attribute name for the given unit string.  
+        Retrieves the unit attribute name for the given unit string.
         For example, if the given unit string is 'metre', 'm' would be returned.
         An exception is raised if an attribute cannot be found.
         """
@@ -165,51 +165,51 @@ class Distance(MeasureBase):
         self.m, self._default_unit = self.default_units(kwargs)
         if default_unit and isinstance(default_unit, str):
             self._default_unit = default_unit
-    
+
     def __getattr__(self, name):
         if name in self.UNITS:
             return self.m / self.UNITS[name]
         else:
             raise AttributeError('Unknown unit type: %s' % name)
-    
+
     def __repr__(self):
         return 'Distance(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
 
     def __str__(self):
         return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
-        
+
     def __cmp__(self, other):
         if isinstance(other, Distance):
             return cmp(self.m, other.m)
         else:
             return NotImplemented
-        
+
     def __add__(self, other):
         if isinstance(other, Distance):
             return Distance(default_unit=self._default_unit, m=(self.m + other.m))
         else:
             raise TypeError('Distance must be added with Distance')
-    
+
     def __iadd__(self, other):
         if isinstance(other, Distance):
             self.m += other.m
             return self
         else:
             raise TypeError('Distance must be added with Distance')
-    
+
     def __sub__(self, other):
         if isinstance(other, Distance):
             return Distance(default_unit=self._default_unit, m=(self.m - other.m))
         else:
             raise TypeError('Distance must be subtracted from Distance')
-    
+
     def __isub__(self, other):
         if isinstance(other, Distance):
             self.m -= other.m
             return self
         else:
             raise TypeError('Distance must be subtracted from Distance')
-    
+
     def __mul__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             return Distance(default_unit=self._default_unit, m=(self.m * float(other)))
@@ -217,14 +217,17 @@ class Distance(MeasureBase):
             return Area(default_unit='sq_' + self._default_unit, sq_m=(self.m * other.m))
         else:
             raise TypeError('Distance must be multiplied with number or Distance')
-    
+
     def __imul__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             self.m *= float(other)
             return self
         else:
             raise TypeError('Distance must be multiplied with number')
-    
+
+    def __rmul__(self, other):
+        return self * other
+
     def __div__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             return Distance(default_unit=self._default_unit, m=(self.m / float(other)))
@@ -251,13 +254,13 @@ class Area(MeasureBase):
         self.sq_m, self._default_unit = self.default_units(kwargs)
         if default_unit and isinstance(default_unit, str):
             self._default_unit = default_unit
-    
+
     def __getattr__(self, name):
         if name in self.UNITS:
             return self.sq_m / self.UNITS[name]
         else:
             raise AttributeError('Unknown unit type: ' + name)
-    
+
     def __repr__(self):
         return 'Area(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
 
@@ -269,46 +272,49 @@ class Area(MeasureBase):
             return cmp(self.sq_m, other.sq_m)
         else:
             return NotImplemented
-        
+
     def __add__(self, other):
         if isinstance(other, Area):
             return Area(default_unit=self._default_unit, sq_m=(self.sq_m + other.sq_m))
         else:
             raise TypeError('Area must be added with Area')
-    
+
     def __iadd__(self, other):
         if isinstance(other, Area):
             self.sq_m += other.sq_m
             return self
         else:
             raise TypeError('Area must be added with Area')
-    
+
     def __sub__(self, other):
         if isinstance(other, Area):
             return Area(default_unit=self._default_unit, sq_m=(self.sq_m - other.sq_m))
         else:
             raise TypeError('Area must be subtracted from Area')
-    
+
     def __isub__(self, other):
         if isinstance(other, Area):
             self.sq_m -= other.sq_m
             return self
         else:
             raise TypeError('Area must be subtracted from Area')
-    
+
     def __mul__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             return Area(default_unit=self._default_unit, sq_m=(self.sq_m * float(other)))
         else:
             raise TypeError('Area must be multiplied with number')
-    
+
     def __imul__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             self.sq_m *= float(other)
             return self
         else:
             raise TypeError('Area must be multiplied with number')
-    
+
+    def __rmul__(self, other):
+        return self * other
+
     def __div__(self, other):
         if isinstance(other, (int, float, long, Decimal)):
             return Area(default_unit=self._default_unit, sq_m=(self.sq_m / float(other)))
@@ -324,7 +330,7 @@ class Area(MeasureBase):
 
     def __nonzero__(self):
         return bool(self.sq_m)
-        
+
 # Shortcuts
 D = Distance
 A = Area

django/contrib/gis/tests/test_measure.py

@@ -95,6 +95,8 @@ class DistanceTest(unittest.TestCase):
 
         d3 = d1 * 2
         self.assertEqual(d3.m, 200)
+        d3 = 2 * d1
+        self.assertEqual(d3.m, 200)
         d3 *= 5
         self.assertEqual(d3.m, 1000)
         
@@ -248,6 +250,8 @@ class AreaTest(unittest.TestCase):
 
         a3 = a1 * 2
         self.assertEqual(a3.sq_m, 200)
+        a3 = 2 * a1
+        self.assertEqual(a3.sq_m, 200)
         a3 *= 5
         self.assertEqual(a3.sq_m, 1000)
         
@@ -319,7 +323,6 @@ class AreaTest(unittest.TestCase):
         self.assertEqual(repr(a1), 'Area(sq_m=100.0)')
         self.assertEqual(repr(a2), 'Area(sq_km=3.5)')
 
-        
 def suite():
     s = unittest.TestSuite()
     s.addTest(unittest.makeSuite(DistanceTest))