[Numpy-discussion] in the NA discussion, what can we agree on?

[Lluís]

Nathaniel Smith writes:
> So assignment is not destructive -- the old value is retained as the "payload".

I never assumed (and I think it is also the case for others) that the payload
was retaining the old value. In fact, AFAIR, the payloads were introduced as a
way of having more than one special value that (if wanted by the user) can be
handled differently depending on the payload.

Note that while you're assuming "IGNORED(x)" means a value that is ignoring the
"x" original value, you're never writing "MISSING(x)" to retain the original
value that is now missing.

Thus I think that decoupling the payload from the "previous value" concept makes
it all consistent regardless of the destructiveness property.

That's one of the reasons why I used the "special value" concept since the
beginning, so that no assumption can be made about its propagation and
destructiveness properties.


Lluis

-- 
 "And it's much the same thing with knowledge, for whenever you learn
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