[Python-ideas] Why is nan != nan?

[Stephen J. Turnbull]

Marcin 'Qrczak' Kowalczyk writes:

 > The original problem with NaN is a consequence of an unfortunate
 > decision to unify numeric equality with object equivalence. If they
 > were distinguished, their behavior would be obvious:
 >   NaN != NaN
 >   NaN eq NaN

What do you mean by that?  NaN is a class, not an instance!

 >   0.0 == -0.0
 >   0.0 ne -0.0
 >   42 == 42.0
 >   42 ne 42.0

As for the other examples, I can only sigh, 'Ah, the joys of "general
abstract nonsense".'[1]  I have some (abstract) sympathy for Mark's
proposal for a with_nonstop_arithmetic context manager, but isn't it
really a YAGNI for the Python language?  (As opposed to high
performance modules like numpy.)

Footnotes: 
[1]  I refer to Bourbaki's(?) name for category theory.