Anyone care to explain why? I also tested a slightly changed program pasted below, and am very confused.
main = do -- This call doesn't terminate, why? print $ nonTermination "a" -- Comment the above line to test the rest of the code -- RTS detects the loop and bails out print $ process "abc" -- Comment the above line to test the rest of the code inp <- readFile "input" -- I'm guessing (process inp) throws an exception, -- and the handler closes all files, making a second close fail? writeFile "output" $ process inp
process :: String -> String process xs = blackhole where blackhole = tail blackhole
nonTermination :: String -> String nonTermination _ = blackhole where blackhole = blackhole
On Thu, Aug 12, 2010 at 3:38 PM, Simon Marlow
On 12/08/10 15:09, Yitzchak Gale wrote:
The file "error_puzzle.hs" begins like this:
main = do inp<- readFile "input" writeFile "output" $ process inp
process :: String -> String
When compiled with GHC 6.12.3 and run, it gives the following result:
$ ./error_puzzle error_puzzle: output: hClose: illegal operation (handle is finalized)
process xs = blackhole where blackhole = tail blackhole
Cheers, Simon _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe