[Haskell-cafe] Exception handling when using STUArray
Denis Bueno
dbueno at gmail.com
Sat Mar 8 09:31:15 EST 2008
On Sat, Mar 8, 2008 at 12:29 AM, Xiao-Yong Jin <xj2106 at columbia.edu> wrote:
> 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?
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.html).
But you must catch exceptions in the IO monad.
> my question is, what the best way to do exception handling
> in STUArray is. Plus, it would be helpful if I can also
> raise an exception in ST monad, but how?
I think what I noted in the last paragraph solves this problem.
--
Denis
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