Am Samstag 06 Februar 2010 13:42:40 schrieb Mark Spezzano:
Hi,
Just wondering whether I can use ShowS or tupling or Difference Lists to speed up the following code?
It's basic text processing. It takes in a list of Lines where each Line is a list of Words and intersperses " " between them then concatenates them into a longer String. Note that there is a recursive call and the ++ operator.
Thanks
Mark
-- Function: joinLines -- Joins the Words within Lines together with whitespace and newline characters -- Argument: Lines to pad with whitespace and newlines -- Evaluate: The processed and concatenated String joinLines :: [Line] -> String joinLines (l:[]) = concat (intersperse " " l) joinLines (l:ls) = (concat (intersperse " " l)) ++ ('\n':joinLines ls)
joinLines = init . unlines . map unwords joinLines = concat . intersperse "\n" . map unwords joinLines = intercalate "\n" . map unwords joinLines = intercalate "\n" . map (intercalate " ") it should be pretty good already, if that's a performance bottleneck, you might need to switch to (Lazy) ByteStrings. I don't think ShowS or difference lists would be any faster.