Re: [Haskell-beginners] Re: Iterating through a list of char...

I understand that higher-order functions are incredibly powerful, and that you can do essentially anything you might ever want while using only 'map' and 'foldl'. However, I have trouble believing that even experienced programmers wold find such HOF-oriented code to be more readable than Mr Akgun's solution: foo :: (a -> a -> a) -> [a] -> [a] foo f (x:y:rest) = f x y : foo f (y:rest) foo f _ = [] It seems to me that 'foo', as defined here, is a direct restatement of the original program specification (the english one). Basically no translation required. If anyone here is enough of a veteran to prefer a map/fold implementation of this spec, I would be interested to hear about the thought processes you undertake when writing such code. Thanks. On Thu, Apr 29, 2010 at 10:22, David Virebayre

wrote:

On Thu, Apr 29, 2010 at 3:52 PM, jean verdier wrote:

...

I may have missed it in this thread, but if not, why didn't anyone suggest:

trans [] = [] trans [x] = [x] trans ('a':_:xs) = 'a' : 'A' : trans xs trans (x:xs) = x : trans xs

While as a beginner (I still am !) I would come up with a solution like this one, on the long run it helps trying to solve those problem with maps, folds, filters, and zips: Eventually, you'll find the code more readable, easier to write, and there's perhaps a better chance that it can be optimised by ghc.

David. _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners

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