Data.Ratio and exceptions

[Kazu Yamamoto ( 山本和彦 )]

Hello Henning,

> I know people get annoyed quickly if I start a new round of "errors
> vs. exceptions" ...

Would you explain how they get annoyed concretely?

> In Haskell there is only one undefined value and that should be
> equivalent to an infinite loop. Every distinction between 'error',
> 'undefined', infinite loop, DivideByZero is only for debugging
> purposes. Don't rely on being able to catch them! The only correct way
> to cope with division by zero is to not let it happen.

Let's define a new constructor of ArithException for debugging
purposes.

--Kazu