Hi, I just feel it is not comfortable to deal with exceptions only within IO monad, so I defined
tryArith :: a -> Either ArithException a tryArith = unsafePerformIO . try . evaluate
and it works quite good as
map (tryArith . (div 5)) [2,1,0,5]
evaluates to
[Right 2,Right 5,Left divide by zero,Right 1]
However, I guess unsafePerformIO definitely has a reason for its name. As I read through the document in System.IO.Unsafe, I can't convince myself whether the use of 'tryArith' is indeed safe or unsafe. I know there have been a lot of discussion around unsafePerformIO, but I still can't figure it out by myself. Can someone share some thoughts on this particular use of unsafePerformIO? Is it safe or not? And why? Thanks, Xiao-Yong -- c/* __o/* <\ * (__ */\ <