homepage

Hi Mark,
I thought that this had all been fixed, but it seems not.
Consider the following:
class xcomplex( complex ):
 def __new__(cls,*args,**kwargs):
 return complex.__new__(cls,*args,**kwargs)
 def __add__(self,x):
 return xcomplex( complex.__add__(self,x) )
 def __radd__(self,x):
 print "larg: ", type(x),"returning: ",
 return xcomplex( complex.__radd__(self,x) )
class xfloat(float):
 def __new__(cls,*args,**kwargs):
 return float.__new__(cls,*args,**kwargs)
 def __add__(self,x):
 return xfloat( float.__add__(self,x) )
 def __radd__(self,x):
 print "larg: ", type(x),"returning: ",
 return xfloat( float.__radd__(self,x) )
z = 1j
xz = xcomplex(1j)
f = 1.0
xf = xfloat(1.0)
print
print "-----------"
print "expect xcomplex:", type(z + xz)
print "expect xcomplex:", type(f + xz)
print "expect xfloat:", type(f + xf)
print "expect ???:", type(z + xf)
When this runs, the first three conversions are fine, the last is not: there
is no call to xfloat.__radd__. It seems that the builtin complex type simply
thinks it is dealing with a float. Here is the output
-----------
expect xcomplex: larg: <type 'complex'> returning: <class
'__main__.xcomplex'>
expect xcomplex: larg: <type 'float'> returning: <class
'__main__.xcomplex'>
expect xfloat: larg: <type 'float'> returning: <class '__main__.xfloat'>
expect ???: <type 'complex'>
The last line shows that no call to __radd__ occurred.
Is there anything that can be done now about this now, or is it just too
late?
Regards
Blair
At 01:13 a.m. 31/05/2010, you wrote:
Mark Dickinson <dickinsm@gmail.com> added the comment:
r78280 didn't remove the implicit coercion for rich comparisons; that's now
been done in r81606.
----------
_______________________________________
Python tracker <report@bugs.python.org>
<http://bugs.python.org/issue5211>
_______________________________________Python tracker <
report@bugs.python.org>