On 10/11/11 18:03, Roman Leshchinskiy wrote:
Oh, I never said it would be easy :-) But this definitely seems like the right thing to do to me.
In the context of this thread, however, it would be perfectly acceptable if NaNs just aborted the program. The original problem was that they mess up things. It is implementation-defined what happens if a computation wants to create a NaN. We could simply say that the program is aborted by default, with a way to turn off this behaviour and just create a NaN. Raising a Haskell exception would certainly be very nice but not essential for this particular problem.
That seems dangerous. This is what happens now if I use unchecked div for example: $ ghci Prelude> GHC.Base.divInt 1 0 Floating point exception $ It exits ghci immediately. Having "0/0" crash would make trusting 'safe' programs much harder. For example, I could no longer make an IRC bot for evaluating numeric expressions, and expect it to keep running. Twan