Coerce with new style classes

Alex Martelli aleax at aleax.it
Mon Feb 24 09:33:49 CET 2003


Blair Hall wrote:

> I can't seem to use coerce with the new style classes,
> any suggestions?

Coercion is going away, though it may be hard to find solid information
about what's going away from where when.

See PEP 208, http://www.python.org/peps/pep-0208.html for more.

In particular, you can find some current details at:
http://www.python.org/doc/current/ref/coercion-rules.html

including:

"""
It is no longer recommended to define a coercion operation. Mixed-mode 
operations on types that don't define coercion pass the original arguments 
to the operation. 

New-style classes (those derived from object) never invoke the __coerce__() 
method in response to a binary operator; the only time __coerce__() is 
invoked is when the built-in function coerce() is called. 
"""

and you're apparently being bitten by the second of these
two points I'm quoting.


Alex





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