Hello,

So I've been trying to print some information in a file. I have two versions of the same function: one of them doesn't work and I don't understand why.

Here are the functions:

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

-- This one works as intended when called from ghci

renderTrackInfosToFile :: FilePath -> String -> IO [TrackInfos] -> IO ()

renderTrackInfosToFile filename sep ls = do nls <- ls

writeFile filename (intercalate "\n" $ map (renderTrackInfo sep) nls)

return ()

-- This one does nothing when called from ghci

renderTrackInfosToFile2 :: FilePath -> String -> [TrackInfos] -> IO ()

renderTrackInfosToFile2 filename sep ls = writeFile filename (intercalate "\n" $ map (renderTrackInfo sep) ls)

renderTrackInfo :: String -> TrackInfos -> String

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Both functions load in ghci, and the following commands are issued:

> -- c :: IO [TrackInfos]

> liftM (renderTrackInfosToFile2 "blabla.txt" "|") c -- this command seems to do absolutely nothing

> renderTrackInfosToFile "blabla.txt" "|" c -- this one works as intended

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

And this is not the first time I have this sort of problem using liftM. I now that I'm missing something important here,

can anyone explain me my mistake?

Much thanks,

Guillaume Basse