Take a look at the monad-loops package. Cheers, Greg On 12/13/2010 06:15 AM, Jacek Generowicz wrote:
-- Is it possible to rewrite code written in this style
untilQuit = do text <- getLine report text if text == "quit" then return () else untilQuit
-- in a style using higher order functions for abstract iteration? For -- example, something along these lines:
untilQuit' = (fmap (takeWhile (/= "quit"))) (sequence $ map (>>= report) (repeat getLine))
-- The latter version shows the report, but it doesn't stop at the -- appropriate place, so I'm guessing that I'm being bitten by my -- ignorance about the interaction of actions and lazyness.
-- For completeness, here's a definition of report report text = do putStrLn $ "You wrote " ++ text return text
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