[Haskell-cafe] Justification for Ord inheriting from Eq?

Jacques Carette carette at mcmaster.ca
Fri Apr 7 13:47:06 EDT 2006

Robert Dockins wrote:
> On Apr 7, 2006, at 9:43 AM, Jacques Carette wrote:
> > [Lots of stuff about IEEE 754]
> Is this an H' worthy item?
It is worth taking a serious look in conjunction with completely redoing 
the Num class.  Minor tweaking of the behaviour on NaNs (which requires 
a large amount of background work) does not seem to be worthwhile on its 
own (in my not-at-all-humble-opinion, having done this before).  If 
getting the Num class "right" is in the cards for H', which probably 
presupposes that some kinds of class alias support is also 'in', then 
looking at a proper implementation of IEEE 754 is worth it.

Note that this would also need that arithmetic operators be able to 
throw signals, which can be either caught and 'handled' or turned 
(automatically) into exceptions.  While 'signals' here can be 
_completely_ independent from O/S signals, it also intersects with 
current discussions on exceptions.

Right now, I am waiting to see where the dust settles on Num, class 
aliases and exceptions.  If it looks like all these things will happen, 
then I will throw my hat in to *do* something about proper IEEE 754 
support for Float, Double, etc.


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