Re: [Haskell-beginners] Folders and sub-folders

26 Feb 2016


      Thanks.


I sweated it  bit more and got


isOk FilePath -> Bool
isOk  = not . isPrefixOf "."  

folders :: FilePath -> IO [FilePath]
folders fp  = do
    all <- getDirectoryContents fp
    z' <- filterM doesDirectoryExist $ map (fp ) (filter isOk all)
    x' <- mapM (\x -> folders x) z'
    return $ z' ++ (concat x') ::

which seems to work.
...
On 25 Feb 2016, at 19:07, Imants Cekusins  wrote:
Hello Mike,
below code find all files recursively from a starting point. It works.
You'd need to tweak it to find folders instead.
import System.Directory
import Data.List
findAllFiles::FilePath -> IO [FilePath]
findAllFiles base0 = gd1 base0
...
...
= \list1 -> concatMap' recurse3 list1
    where gd1 d1 = filter f2 <$> (getDirectoryContents d1)
          f2 "." = False
          f2 ".." = False
          f2 _ = True
          recurse3 md3 = doesDirectoryExist md3full
= \isDir3 ->
                       if isDir3 then findAllFiles md3full
                       else pure [md3full]
                   where md3full = base0 ++ "/" ++ md3
concatMap':: (a -> IO [b]) -> [a] -> IO [b]
concatMap' m0 list0 = sequence (m0 <$> list0)
...
...
= \list2 -> pure $ concat list2

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Re: [Haskell-beginners] Folders and sub-folders

Mike Houghton