Re: [Haskell-cafe] Exception handling when using STUArray

"Denis Bueno" writes:

On Sat, Mar 8, 2008 at 12:29 AM, Xiao-Yong Jin wrote:

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I'm using STUArray in some of my time critical number crunching code. I would like to know some way to catch the exceptions raised in the ST monad, ie. ArrayException.

I am also using STUArray from some time-critical code; however, I don't deal with ArrayException, or any exceptions for that matter. What besides an out-of-bounds read or write might throw an ArrayException? If it is out-of-bounds reading or writing, surely that indicates a bug in your program that you'd rather fix than catch the exception, no?

In my case, because I choose a index of the array according to certain value in the array, if there is NaN or Infinity in the array, the code breaks. So I guess, to fix the code, I would probably use isNaN/isInfinite and throw an exception when that happens.

Also, if you're using GHC, note that the ArrayException documentation says:

"(NOTE: GHC currently does not throw ArrayExceptions)."

...

Looking through the Control.Exception module, I understand that those functions can only be used within IO monad. So

This isn't quite true, if I understand what you mean. The function throw can be used from any code (http://haskell.org/ghc/docs/latest/html/libraries/base/Control-Exception.htm...). But you must catch exceptions in the IO monad.

Thanks for the clarification. I didn't read the documentation carefully. I'll experiment on `throw', right now. Xiao-Yong -- c/* __o/* <\ * (__ */\ <