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------------------------------------------------------------------------------ --- Library containing unsafe operations. --- These operations should be carefully used (e.g., for testing or debugging). --- These operations should not be used in application programs! --- --- @author Michael Hanus, Bjoern Peemoeller --- @version September 2013 --- @category general ------------------------------------------------------------------------------ module Unsafe ( unsafePerformIO, trace ) where import Char (isSpace) import IO (hPutStrLn, stderr) --- Performs and hides an I/O action in a computation (use with care!). unsafePerformIO :: IO a -> a unsafePerformIO external --- Prints the first argument as a side effect and behaves as identity on the --- second argument. trace :: String -> a -> a trace s x = unsafePerformIO (hPutStrLn stderr s >> return x) |