Am Samstag, den 06.02.2010, 23:12 +1030 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)
You should use the existing library functions and leave the optimisations to their implementor: import Data.List joinLines :: [[String]] -> String joinLines = intercalate "\n" . map (intercalate " ") Now you can easily switch to the faster ByteString library by simply changing the import statement.