Re: [pure-lang-users] complex 0

[Eddie R. <er...@bm...>]

On Tue, 2008-09-09 at 13:00 +0200, Albert Graef wrote:

> Yes, you are, I'm afraid. :) The Scheme way doesn't make much sense 
> there because log is always an inexact operation.

What about ln 1? Scheme has a different philosophy from Pure: all
operations *try* to return an exact value if the operation's argument(s)
are exact. 

(log 1) => 0 ; an exact 0 not an approximated 0.0
(sin 0) => 0
(cos 0) => 1 ; an exact 1
(sqrt 4) => 2 ; an exact 2
(sqrt -4) => 0+2i ; no approximations on the img part.
(/ 1 3) => 1/3 
(expt 16 1/2) => 4 
(expt 8 1/3) => 2.0 ; uh oh? My Casio gives the exact value of 2 here.
What does you HP give?

I'm not disagreeing with your reasoning that Pure should promote its
argument(s) to inexact values like C does though. I think I've totally
chased the rabbit away from my original question which was about
consistency for which you found the answer in a later post. My arm is
getting tired of flogging. I'll shut up and go back to work now ;-) 

e.r.