dave at zednenem.com
Sat Apr 8 03:02:50 EDT 2006
John Meacham writes:
> On Fri, Apr 07, 2006 at 10:00:21AM -0500, John Goerzen wrote:
> > But here's my concern. Let's say that I wanted to, for some
> > reason, create a MultiplyByZero exception. It should be broadly
> > considered an ArithException, and any code that catches an
> > ArithException should be able to catch my MultiplyByZero exception.
> > But the ArithException type is limited to storing errors that are
> > defined by Control.Exception.ArithException. My MultiplyByZero is
> > not defined there, so I am out of luck. The best I could do is
> > define a new MultiplyByZero, and catch it in my own code. But any
> > code that others have written to catch ArithExceptions would be
> > blind to MultiplyByZero.
> newtype ArithException a = ArithException a
> data DivideByZero
> throw (ArithException DivideByZero)
> your code:
> data MultiplyByZero
> throw (ArithException MultiplyByZero)
How would you use this to write a handler that captures any
David Menendez <zednenem at psualum.com> | "In this house, we obey the laws
<http://www.eyrie.org/~zednenem> | of thermodynamics!"
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