On Dec 3, 2004, at 1:28 PM, Steven Huwig wrote:
I am basically a newbie at Haskell, and have been experimenting with it where typically I would use Python. ... 2) Do unravel and ravel have any other practical uses on their own? Looking at it, I think they could be used in a single function of type f :: (a->Bool) -> ([a] -> [a]) -> [a] -> [a] Can one get that function out of the Prelude in an easier manner than above? Is there a simpler way to get that functionality besides composing ravel and unravel with a map in between?
(Bad form to self-reply, I know.) The answer to that question is yes. -- mapGroups :: (a -> Bool) -> ([a] -> [a]) -> [a] -> [a] mapGroups = mapGroups' [] mapGroups' :: [a] -> (a -> Bool) -> ([a] -> [a]) -> [a] -> [a] mapGroups' acc _ _ [] = acc mapGroups' acc p f z@(x:_) | p x = mapGroups' (acc ++ f part1) p f part2 | otherwise = mapGroups' (acc ++ part1') p f part2' where (part1, part2) = span p z (part1', part2') = span (not . p) z mapWords = mapGroups (not . isSpace) initcap :: String -> String initcap (c:cs) = toUpper c:[toLower c' | c' <- cs] main = putStrLn (mapWords initcap "This\nis\t\ta test\n") -- Now I can solicit your remarks yet again :) -- Steven Huwig