At 11:17 +0100 2001/11/02, Lennart Augustsson wrote: >Are you using projective or affine infinity?
At 10:26 +0000 2001/11/02, Simon Marlow wrote: >I have absolutely no idea. Which one should we be using? How do we >find out which one we are using? My guess is that by "affine infinity" Lennart means +oo/-oo, but what you are using in GHCi is what the FPU is producing, probably a NaN for every computation it cannot perform. This NaN roughly corresponds to saying that there has been an exception without specifying what it consist of (think of the exception monad!). I think the best approach would be to throw an exception by every computation can cannot be computed, with an additional information of what type the problem is (like divide by zero, square root of negative, etc). Then on top of that can build new types with the desired behavior. -- Thus, the basic floating point type should not have any infinities or such (but throw an exception, or treat NaN as a thrown exception). Hans Aberg _______________________________________________ Hugs-Bugs mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/hugs-bugs
