Be careful, though. This only works if there's a single constructor
for your exception type. If there are multiple, you should write it
like this:
thing_to_try `catch` \(e :: MyErrorType) -> case e of MyError1 _ ->
..; MyError2 _ -> ...
If you write `catch` (MyError1 ...) and a MyError2 is thrown, you will
get a pattern match error exception.
If you want to catch multiple exceptions (of different type) at once,
use the "catches" combinator.
2008/11/22 Ross Mellgren
I think catch is now basically what catchJust was -- you can just do
thing_to_try `catch` (\ (ErrorCall s) -> putStrLn s)
and it will only catch ErrorCall exceptions.
-Ross
David F. Place wrote:
Hi, All.
I am trying to understand the new exceptions package in base-4 Control.Exceptions. The documentation for catchJust is the same as in Control.OldException including this example:
result <- catchJust errorCalls thing_to_try handler
Control.OldException provides the predicate errorCalls, but the new one does not. I don't see how to write it.
Thanks for reading.
Cheers, David
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