2008/9/30 wman <[EMAIL PROTECTED]>: > I got asked how to do one particular thing in excel, which led to discssion > with "our local MSOffice expert". > During the discussion I stated that's it too much of a PITA and that I'd > rather write a script. > Long story short, I promised him a one-liner to "show the power and beauty > of Haskell". > > I got the csv package from hackage, modified the parseCSVFromFile so it's > returns IO CSV rather than IO (Either ParseError CSV), and finished with > following code > > (writeFile "output.csv") =<< (liftM printCSV $ liftM (map updateLine) $ > parseCSVFromFile "input.csv") > > Is there room for improvement ? > Could it still be made into one-liner without modifying the csv module (and > without resorting to > case parseCSVFromFile "input.csv" of { Left _ -> []; Right x -> x} > kind of tricks) ? >
I have good news for you: either :: (b ->c) (a -> c) (Either b a) -> c That type signature is from memory, but you get the idea. You pass in two functions - one to deal with the Left and the other to deal with the Right, and it sorts out your result for you. Cheers, D -- Dougal Stanton [EMAIL PROTECTED] // http://www.dougalstanton.net _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe