Pete Kazmier wrote:
import Data.ByteString.Lazy.Char8 as B hiding (map,foldr) import Data.List (map) import Data.Map as M hiding (map)
-- This will be populated from a file dict = M.singleton (B.pack "Pete") (B.pack "Kazmier")
main = B.interact $ B.unlines . map doline . B.lines where doline = B.join comma . mapIndex fixup . B.split ',' comma = B.singleton ',' fixup 3 s = M.findWithDefault s s dict fixup n s = s
-- f is supplied the index of the current element being processed mapIndex :: (Int -> ByteString -> ByteString) -> [ByteString] -> [ByteString] mapIndex f xs = m xs 0 where m [] _ = [] m (x:xs') i = f i x : (m xs' $! i+1)
How about import Data.ByteString.Lazy.Char8 as B hiding (map,foldr) import Data.List (map) import Data.Map as M hiding (map) dict = M.singleton (B.pack "Pete") (B.pack "Kazmier") main = B.interact $ B.unlines . map doline . B.lines where doline = B.join comma . zipWith ($) fixup9 . B.split ',' fixup9 = fixup 9 fixup n = replicate n id ++ [\s -> M.findWithDefault s s dict] ++ repeat id Note that fixup9 is shared intentionally across different invocations of doline. The index n starts at 0. Also note that because (compare :: (Byte)String -> ..) takes time proportional to the string length, the use of Map will inevitably introduce a constant factor. But I'm still happy you didn't use arrays or hash tables (urgh!) :) In any case, tries are *the* natural data structure for (in)finite maps in functional languages, see also Ralf Hinze. Generalizing generalized tries. Journal of Functional Programming, 10(4):327-351, July 2000 http://www.informatik.uni-bonn.de/~ralf/publications/GGTries.ps.gz Regards, apfelmus