guibou · December 9, 2017 23:26 · Dec 9, 2017 · Dec 9, 2017
diff --git a/Interop.hs b/Interop.hs
@@ -3,7 +3,6 @@
     - Read all folders and sub-folders with structure like below
     - store all folder and file info in State monad, 
     - at the end of the loop, print it.
-
     ├── aaa
     │   ├── b
     │   │   ├── b1
@@ -17,27 +16,30 @@
     │       └── c2
   
   Goal: to practice using State and IO monad together by leveraging liftIO and unsafePerformIO
-
   Would appreciate any correction, better way to do it or generic advices
-
 -}
 module Main where
 
-import Control.Monad.State
 import Control.Monad.State
 import System.Directory
 import System.Exit
 import System.FilePath
+import Data.Time
+
+import Control.Monad.Extra (partitionM)
 
-main :: IO ([Dir], [File], Root)
+main :: IO ([Dir], [File])
 main
  = do
-  ~(_, s@(d, f, r)) <- runStateT k ([], [], "aaa")
-  putStrLn $ "Root: " ++ r
+  let root = "/tmp/poulet"
+  s@(d, f) <- k root
+  putStrLn $ "Root: " ++ root
+
   pretty d True "DIR:"
   pretty f True "FILE:"
   return s
 
+-- | Order is arbitrary
 pretty :: Show a => [a] -> Bool -> String -> IO ()
 pretty src rev prefix = do
   putStrLn $ "\n" ++ prefix ++ "\n"
@@ -47,60 +49,48 @@ pretty src rev prefix = do
 
 data File = File
   { name :: String
-  , date :: String
+  , date :: UTCTime
   , size :: Integer
   , content :: String
   } deriving (Show)
 
 data Dir = Dir
   { dirName :: String
-  , dirDate :: String
+  , dirDate :: UTCTime
   , dirContent :: [FilePath]
   } deriving (Show)
 
-type Root = String
+k :: String -> IO ([Dir], [File])
+k root = do
+  isDir <- doesDirectoryExist root
+  unless isDir $ die "not a dir"
+  execStateT (list root) ([], [])
+
+list :: String -> StateT ([Dir], [File]) IO ()
+list path = do
+  -- walk current directory
+  dir <- liftIO $ do
+    children <- listDirectory path
+    dt <- getModificationTime path
+    return Dir {dirName = path, dirContent = children, dirDate = dt}
+  modify (\(ds, fs) -> (dir : ds, fs))
+
+  -- remove unwanted files and prepend directory name
+  let
+    fullPaths = map (path</>) (dirContent dir)
+    filteredFiles = filter (/=".DS_Store") fullPaths
+
+  -- Split between sub directories and sub files
+  (subDirs, subFiles) <- liftIO (partitionM doesDirectoryExist filteredFiles)
+
+  -- recursivly walk sub directories
+  forM_ subDirs list
 
-k :: StateT ([Dir], [File], Root) IO ()
-k = do
-  (_, _, root) <- get
-  liftIO $ do
-    isDir <- doesDirectoryExist root
-    unless isDir $ die "not a dir"
-  list root
-  where
-    list :: String -> StateT ([Dir], [File], Root) IO ()
-    list path = do
-      dir <-
-        liftIO $
-         do
-          children <- withCurrentDirectory path $ listDirectory "."
-          dt <- getModificationTime path
-          return Dir {dirName = path, dirContent = children, dirDate = show dt}
-      _ <- withStateT (\(ds, fs, root) -> (dir : ds, fs, root)) get
-      n <-
-        liftIO $
-        foldM
-          (\acc@(dirs, files) f -> do
-             let fullPath = path </> f
-             if (f == ".DS_Store")
-               then return acc
-               else do
-                 bool <- doesDirectoryExist fullPath
-                 if bool
-                   then return (dirs ++ [fullPath], files)
-                   else return (dirs, files ++ [fullPath]))
-          ([], []) -- acc, ([dirs], [files])
-         $
-        dirContent dir
-      forM_ (fst n) list
-      files <-
-        liftIO $
-        mapM
-          (\f -> do
-             s <- getFileSize f
-             dt <- getModificationTime f
-             c <- readFile f
-             return File {name = f, date = show dt, size = s, content = c})
-          (snd n)
-      _ <- withStateT (\(ds, fs, root) -> (ds, files ++ fs, root)) get
-      return ()
+  -- handle files in the current directory
+  forM_ subFiles $ \f -> do
+         file <- liftIO $ do
+           s <- getFileSize f
+           dt <- getModificationTime f
+           c <- readFile f
+           return File {name = f, date = dt, size = s, content = c}
+         modify (\(ds, fs) -> (ds, file:fs))
diff --git a/Interop.hs b/Interop.hs
@@ -0,0 +1,106 @@
+{-
+  Functionality: 
+    - Read all folders and sub-folders with structure like below
+    - store all folder and file info in State monad, 
+    - at the end of the loop, print it.
+
+    ├── aaa
+    │   ├── b
+    │   │   ├── b1
+    │   │   │   ├── b1-1
+    │   │   │   └── b1-2
+    │   │   └── b2
+    │   │       └── 2-1
+    │   │           └── b2-1-1
+    │   └── c
+    │       ├── c1
+    │       └── c2
+  
+  Goal: to practice using State and IO monad together by leveraging liftIO and unsafePerformIO
+
+  Would appreciate any correction, better way to do it or generic advices
+
+-}
+module Main where
+
+import Control.Monad.State
+import Control.Monad.State
+import System.Directory
+import System.Exit
+import System.FilePath
+
+main :: IO ([Dir], [File], Root)
+main
+ = do
+  ~(_, s@(d, f, r)) <- runStateT k ([], [], "aaa")
+  putStrLn $ "Root: " ++ r
+  pretty d True "DIR:"
+  pretty f True "FILE:"
+  return s
+
+pretty :: Show a => [a] -> Bool -> String -> IO ()
+pretty src rev prefix = do
+  putStrLn $ "\n" ++ prefix ++ "\n"
+  if rev
+    then mapM_ print $ reverse src
+    else mapM_ print src
+
+data File = File
+  { name :: String
+  , date :: String
+  , size :: Integer
+  , content :: String
+  } deriving (Show)
+
+data Dir = Dir
+  { dirName :: String
+  , dirDate :: String
+  , dirContent :: [FilePath]
+  } deriving (Show)
+
+type Root = String
+
+k :: StateT ([Dir], [File], Root) IO ()
+k = do
+  (_, _, root) <- get
+  liftIO $ do
+    isDir <- doesDirectoryExist root
+    unless isDir $ die "not a dir"
+  list root
+  where
+    list :: String -> StateT ([Dir], [File], Root) IO ()
+    list path = do
+      dir <-
+        liftIO $
+         do
+          children <- withCurrentDirectory path $ listDirectory "."
+          dt <- getModificationTime path
+          return Dir {dirName = path, dirContent = children, dirDate = show dt}
+      _ <- withStateT (\(ds, fs, root) -> (dir : ds, fs, root)) get
+      n <-
+        liftIO $
+        foldM
+          (\acc@(dirs, files) f -> do
+             let fullPath = path </> f
+             if (f == ".DS_Store")
+               then return acc
+               else do
+                 bool <- doesDirectoryExist fullPath
+                 if bool
+                   then return (dirs ++ [fullPath], files)
+                   else return (dirs, files ++ [fullPath]))
+          ([], []) -- acc, ([dirs], [files])
+         $
+        dirContent dir
+      forM_ (fst n) list
+      files <-
+        liftIO $
+        mapM
+          (\f -> do
+             s <- getFileSize f
+             dt <- getModificationTime f
+             c <- readFile f
+             return File {name = f, date = show dt, size = s, content = c})
+          (snd n)
+      _ <- withStateT (\(ds, fs, root) -> (ds, files ++ fs, root)) get
+      return ()
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