Re: Distinction between 1/0 and 1/Empty

["Nate Hayes" <nh@xxxxxxxxxxxxxxxxx>]

Arnold Neumaier wrote:
> Nate Hayes wrote:
> > That's all sensible, but I don't see it constitutes an advantage: it 
> > simply trades one shortcoming for another.
> >
> > I would support adding a new decoration, i.e., expanding the total number 
> > of decorations from five to six:
> >
> >    D4 = safe (defined, continuous, bounded)
> >    D3 = everywhere defined
> >    D2 = somewhere defined, somewhere undefined
> >    D1 = everywhere undefined on real inputs (e.g., 1/0)
> >    D0 = everywhere undefined on empty input (e.g., 1/Empty)
> >    DX = ill-formed (bug)
> >
> > Newbie-friendly functions such as isUndefined() can simply return TRUE if
> > the decoration is D1 or D0, and DX is then reserved as you and Jurgen 
> > would
> > like as special case for things such as invalid constructions and/or 
> > uninitialized data, etc.
>
> My proposal allows to split decorations; but the splitting should not be 
> made mandatory. So the standard should not distinguish between 1/0 and 
> 1/Empty, but implementations that care for finer information are free to 
> split it.
>
> Thus both you and I can be satisfied.


Well, our proposal allows splitting of decorations, as well, so I could say 
the same to you. But something tells me you wouldn't be satisfied with that 
for the same reasons I wouldn't be satisfied with what you just mentioned. 
;-)

No, I think the six decorations should be standardized. At least, that is 
something I would finally vote yes for.

Nate