[Haskell-cafe] Real World Haskell Chapter 19 and GHC 6.10
mpm at alumni.caltech.edu
Wed Oct 21 05:29:53 EDT 2009
The examples in the "error handling" chapter (19) of RWH don't run under
For instance, an example might be
main = handle (\_ -> putStrLn "error") (print $ 5 `div` 0)
Trying to load this results in "amigous type variable 'e' in the
constraint: 'Exception e' arising from a use of 'handle' etc etc.
I was able to fix this via the ludicrously complex:
main2 = (handle :: (SomeException -> IO ()) -> IO () -> IO ())
(\_ -> putStrLn "Error calculating result")
(print $ 5 `div` 0)
Is there a more concise way to use "handle", or can someone point me to a
tutorial that might explain the changes in 6.10 and in a general way how to
get the RWH examples to run?
More information about the Haskell-Cafe