[MATRIX-SIG] Much ado about nothingness.

[Jim Fulton]

Ted Horst wrote:
> 
> Has anybody looked at the Missing type from DigiCool ? 

(Actually, Digital Creations, aka DC :)

> It has the desired
> behavior for arithmetic operations, but doesn't work correctly for math or
> umath functions.  I have no idea how hard this would be to get working,

This would be easy.  I'm been meaning too....so little time. :-(

I'd be happy to do this if needed.

> or even
> if this is the proper approach,

Good question. There is the sticky issue that you can't actually
store one of these things in a numeric array.  You would have to 
pick a "special" numeric value and map to and from it on input and
output.  I think this is a good thing to do, but others disagree
with me.

> but somebody else is at least looking at the
> problem.  You can get it from http://www.digicool.com/releases/ExtensionClass/.

I also think it would be a good thing for the Numeric types to be 
extension classes, so that they could be subclassed in Python.
 
Jim

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