Should this be correct behaviour?

[Sean Kelly]

Janice Caron wrote:
> On Nov 30, 2007 12:23 AM, Sean Kelly <sean at f4.ca> wrote:
>> If NaNs compared not equal via
>> TypeInfo comparisons
> 
> They don't compare not equal even in normal use. They compare as being
> neither == nor !=.
> 
> (I know you know that. Just trying to be precise here).
> 
>> then any NaN used as an AA key would result in an
>> insertion that was lost forever.  With this in mind, I think the current
>> behavior makes the most sense as well.
> 
> There is another way of looking at it though. Using NaN as array key
> sounds like a bug to me. Should it even be permitted? Let's think this
> through - the interpretation of NaN here is either "unassigned
> variable", or "I don't know the answer" (for example, infinity divided
> by infinity). Is it even sensible to allow such a beast to be an array
> key?

Probably not.  I guess the array code could test if the value being 
inserted were equal to itself and if so, throw an exception?  Seems a 
bit of a corner case to test for explicitly though.


Sean