Evaluation Question

[Hal Daume III]

For each call, I believe.  An exception might be if the call to nco is
inlined into the calling function, but this is unlikely as nco is
recursive.

So, you're probably better off with:

> nco wn = nco'
>     where wn'  = cis wn
>           nco' = 1 : map (wn'*) nco'

In which case it will only be evaluated once.

HTH.

--
Hal Daume III

 "Computer science is no more about computers    | hdaume@isi.edu
  than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

On Sat, 11 Jan 2003, Matthew Donadio wrote:

> Hi all,
> 
> I have a question about lazy evaluation.  In the following function:
> 
> > nco    :: RealFloat a => a -> [ Complex a ]
> > nco wn = 1 : map ((*) (cis wn)) (nco wn)
> 
> will the sin and cos associated with cis be evaluated once, or for each
> call?
> 
> Thanks.
> 
> -- 
> Matthew Donadio (m.p.donadio@ieee.org)
> _______________________________________________
> Haskell mailing list
> Haskell@haskell.org
> http://www.haskell.org/mailman/listinfo/haskell
>