Since there are many useful per-line functions, do a little refactoring,
placing the following into a library:
perLine :: (String -> String) -> (String -> String)
perLine f = unlines . map f . lines
On Dec 12, 2007 12:43 PM, apfelmus
Tommy M McGuire wrote:
(Plus, interact is scary. :-D )
You have a scary feeling for a moment, then it passes. ;)
Gwern Branwen wrote:
I... I want to provide a one-liner for 'detab', but it looks impressively monstrous and I'm not sure I understand it.
On the other hand, I'm not looking for one-liners; I really want clarity as opposed to cleverness.
tabwidth = 4
-- tabstop !! (col-1) == there is a tabstop at column col -- This is an infinite list, so no need to limit the line width tabstops = map (\col -> col `mod` tabwidth == 1) [1..]
-- calculate spaces needed to fill to the next tabstop in advance tabspaces = snd $ mapAccumR addspace [] tabstops addspace cs isstop = let cs'=' ':cs in (if isstop then [] else cs',cs')
main = interact $ unlines . map detabLine . lines where detabLine = concat $ zipWith replace tabspaces replace cs '\t' = cs -- replace with adequate number of spaces replace _ char = [char] -- pass through
How about that?
Regards, apfelmus
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