Re: [q-lang-users] Exponentiation operator

[Albert G. <Dr....@t-...>]

Rob Hubbard wrote:
> All the functions return a "normalised" value. Thus a simple way to 
> implement the other behaviour is to change "normalisation" to reduce to 
> Int when possible.

You will find that those cases are already treated separately (for 
optimization purposes) in the prototype stdlib rational.q that I sent 
you in private mail. So the necessary changes are in fact trivial.

> There's a chance that some of my algorithms will need 
> to be tweaked afterwards, as sometimes I assume in some private 
> functions that a value is in the form (rat N D).

Those parts of your module will end up in the separate ratutils.q module 
and thus need to be rewritten anyway, because ratutils won't have access 
to the rat constructor any more (which is private to rational.q). I've 
already checked this, the necessary changes should be rather minimal.

BTW, even if we don't decide for the "auto-simplification", I'd like to 
propose that the numerator, denominator and num_den functions should 
accept Int arguments, too, then _all_ operations in the rational base 
module would work on Rational and Int alike. This would also be 
analogous to complex.q, where 're' and 'im' are also defined on Real.

> I think that the behaviour ought to follow the style of what you do with 
> (^).

Ok, so that would mean that we never promote the result to a type less 
general that the argument types. Fair enough. That's what effectively 
happens in Haskell, too, AFAICS.

John, you argued in favour of "auto-simplification", do you think you 
can also live without it?

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag