type classes and generality

Alexander V. Voinov [email protected]
Mon, 09 Jul 2001 18:28:23 -0700


Hi All,

Lennart Augustsson wrote:
> > Each pseudorandom generator generates a countable sequence of values,
> > which is isomorphic to a sequence of integers. In good old (Turbo)C we
> > got something between 0 and MAXINT and then divided by (double)MAXINT.
> > Can't _this_ be done in Haskell?
> 
> Of course it can be done, but not in class Real, you have to be in Fractional.
> I'm not sure why Real would be the class of choice for this problem anyway.
> I'd think that Fractional or RealFrac would be more appropriate.

I apologize for ignorance, I probably did not read this part of the doc
attentively. But informally, the word 'Real' is widely used to denote a
completely ordered field, and there is a theorem to change 'a' to 'the'. 
It's counterintuitive to use Real in any other meaning, I think.

Alexander