coloring a complex number

[Brandon K]

I'm not 100% sure about this, but from what it seems like, the reason 
method B worked, and not method a is because class foo(complex) is 
subclassing a metaclass.  So if you do this, you can't init a meta class 
(try type(complex), it equals 'type' not 'complex'.  type(complex()) 
yields 'complex'), so you use the new operator to generator a class on 
the fly which is why it works in method B.  I hope that's right.

-Brandon
> Spending the morning avoiding responsibilities, and seeing what it would
> take to color some complex numbers.
> 
> class color_complex(complex):
>         def  __init__(self,*args,**kws):
>                 complex.__init__(*args)
>                 self.color=kws.get('color', 'BLUE')
> 
>>>> a=color_complex(1,7)
>>>> print a
> (1+7j)                                                      #good so far
>>>> a=color_complex(1,7,color='BLUE') 
> Traceback (most recent call last):
>  File "<pyshell#37>", line 1, in -toplevel-
>    a=color_complex(1,7,color='BLUE')
> TypeError: 'color' is an invalid keyword argument for this function
> 
> No good... it seems that I am actually subclassing the built_in function
> 'complex' when I am hoping to have been subclassing the built_in numeric
> type - complex.
> 
> but some googling sends me to lib/test/test_descr.py
> 
> where there a working subclass of complex more in
> accordance with my intentions.
> 
> class color_complex(complex):
>    def __new__(cls,*args,**kws):
>            result = complex.__new__(cls, *args)
>            result.color = kws.get('color', 'BLUE')
>            return result
> 
>>>> a=color_complex(1,7,color='BLUE')
>>>> print a
> (1+7j)
>>>> print a.color
> BLUE
> 
> which is very good.
> 
> But on the chance that I end up pursuing this road, it would be good if
> I understood what I just did. It would certainly help with my
> documentation  ;)
> 
> Assistance appreciated.
> 
> NOTE:
> 
> The importance of the asset of the depth and breadth of Python archives
> -  for learning (and teaching) and real world production - should not be
> underestimated, IMO. I could be confident if there was an answer to
> getting the functionality I was looking for as above, it would be found
> easily enough by a google search.  It is only with the major
> technologies that one can hope to pose a question of almost any kind to
> google and get the kind of relevant hits one gets when doing a Python
> related search.  Python is certainly a major technology, in that
> respect.  As these archives serve as an extension to the documentation,
> the body of Python documentation is beyond any  normal expectation.
> 
> True, this asset is generally better for answers than explanations.
> 
> I got the answer I needed.  Pursuing here some explanation of that answer.
> 
> Art
> 
> 


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