[Haskell] Literal for Infinity

Frederik Eaton frederik at a5.repetae.net
Sun Oct 2 09:46:29 EDT 2005

I've previously mentioned that I would like to see an 'instance
Bounded Double' etc., as part of the standard, which would use 1/0 for
maxBound, or the largest possible value (there must be one!) for
platforms where that is not possible. I don't see a problem with
looking at Double values as if they were bounded by -infinity and

On Thu, Sep 29, 2005 at 09:11:25PM +0300, Yitzchak Gale wrote:
> Hi Jacques,
> Thanks also to you for a most interesting reply.
> This same discussion has taken place on the
> discussion list of every modern general-purpose
> programming language.
> The same points are always raised and argued, and
> the conclusion is always the same: floating point
> exceptions should raise exceptions.  Programs that
> are so sensitive that the tiny overhead makes a
> difference should use numeric libraries, unboxed
> types, FFI, and the like.
> In Haskell also, it looks like the infrastructure
> was already laid in the Control.Exception module.
> I hope we will soon be using it.
> I personally would like also to see alternative
> functions that return values in the Error monad.
> Regards,
> Yitz
> On Thu, Sep 29, 2005 at 03:13:27PM +0300, Jacques Carette wrote:
> > The IEEE 754 standard says (fairly clearly) that +1.0 / +0.0 is one of 
> > the most 'stable'  definitions  of Infinity (in  Float at least).  
> > Throwing an exception is also regarded as a possibility in IEEE 754, but 
> > it is expected that that is not the default, as experience shows that 
> > that is a sub-optimal default.  Mathematical software (Maple, 
> > Mathematica, Matlab) have generally moved in that direction.
> > 
> > Almost all hardware implementations of float arithmetic now default to 
> > IEEE 754 arithmetic.  Having the arithmetic do 'something else' involves 
> > more CPU cycles, so users should generally complain if their system's 
> > arithmetic differs from IEEE 754 arithmetic without some deep reason to 
> > do so [there are some; read and understand William Kahan's papers for 
> > these].
> > 
> > Jacques
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