Fix Async actions from evaluating too early

Author: garyb

src/Node/FS/Async.purs

@@ -72,7 +72,13 @@ foreign import fs "var fs = require('fs');" ::
   , readFile :: forall a opts. Fn3 FilePath { | opts } (JSCallback a) Unit
   , writeFile :: forall a opts. Fn4 FilePath a { | opts } (JSCallback Unit) Unit
   , appendFile :: forall a opts. Fn4 FilePath a { | opts } (JSCallback Unit) Unit
+  , exists :: forall a. Fn2 FilePath (Boolean -> a) Unit
   }
+  
+foreign import mkEff
+  "function mkEff(action) {\
+  \  return action;\
+  \}" :: forall eff a. (Unit -> a) -> Eff eff a
 
 -- |
 -- Type synonym for callback functions.
@@ -87,7 +93,7 @@ rename :: forall eff. FilePath
                    -> Callback eff Unit
                    -> Eff (fs :: FS | eff) Unit
 
-rename oldFile newFile cb = return $ runFn3
+rename oldFile newFile cb = mkEff $ \_ -> runFn3
   fs.rename oldFile newFile (handleCallback cb)
 
 -- |
@@ -98,7 +104,7 @@ truncate :: forall eff. FilePath
                      -> Callback eff Unit
                      -> Eff (fs :: FS | eff) Unit
 
-truncate file len cb = return $ runFn3
+truncate file len cb = mkEff $ \_ -> runFn3
   fs.truncate file len (handleCallback cb)
 
 -- |
@@ -110,7 +116,7 @@ chown :: forall eff. FilePath
                   -> Callback eff Unit
                   -> Eff (fs :: FS | eff) Unit
 
-chown file uid gid cb = return $ runFn4
+chown file uid gid cb = mkEff $ \_ -> runFn4
   fs.chown file uid gid (handleCallback cb)
 
 -- |
@@ -121,7 +127,7 @@ chmod :: forall eff. FilePath
                   -> Callback eff Unit
                   -> Eff (fs :: FS | eff) Unit
 
-chmod file mode cb = return $ runFn3
+chmod file mode cb = mkEff $ \_ -> runFn3
   fs.chmod file mode (handleCallback cb)
 
 -- |
@@ -131,7 +137,7 @@ stat :: forall eff. FilePath
                  -> Callback eff Stats
                  -> Eff (fs :: FS | eff) Unit
 
-stat file cb = return $ runFn2
+stat file cb = mkEff $ \_ -> runFn2
   fs.stat file (handleCallback $ cb <<< (<$>) Stats)
 
 -- |
@@ -142,7 +148,7 @@ link :: forall eff. FilePath
                  -> Callback eff Unit
                  -> Eff (fs :: FS | eff) Unit
 
-link src dst cb = return $ runFn3
+link src dst cb = mkEff $ \_ -> runFn3
   fs.link src dst (handleCallback cb)
 
 -- |
@@ -154,7 +160,7 @@ symlink :: forall eff. FilePath
                     -> Callback eff Unit
                     -> Eff (fs :: FS | eff) Unit
 
-symlink src dest ty cb = return $ runFn4
+symlink src dest ty cb = mkEff $ \_ -> runFn4
   fs.symlink src dest (show ty) (handleCallback cb)
 
 -- |
@@ -164,7 +170,7 @@ readlink :: forall eff. FilePath
                      -> Callback eff FilePath
                      -> Eff (fs :: FS | eff) Unit
 
-readlink path cb = return $ runFn2
+readlink path cb = mkEff $ \_ -> runFn2
   fs.readlink path (handleCallback cb)
 
 -- |
@@ -174,7 +180,7 @@ realpath :: forall eff. FilePath
                      -> Callback eff FilePath
                      -> Eff (fs :: FS | eff) Unit
 
-realpath path cb = return $ runFn3
+realpath path cb = mkEff $ \_ -> runFn3
   fs.realpath path {} (handleCallback cb)
 
 -- |
@@ -186,7 +192,7 @@ realpath' :: forall eff cache. FilePath
                             -> Callback eff FilePath
                             -> Eff (fs :: FS | eff) Unit
 
-realpath' path cache cb = return $ runFn3
+realpath' path cache cb = mkEff $ \_ -> runFn3
   fs.realpath path cache (handleCallback cb)
 
 -- |
@@ -196,7 +202,7 @@ unlink :: forall eff. FilePath
                    -> Callback eff Unit
                    -> Eff (fs :: FS | eff) Unit
 
-unlink file cb = return $ runFn2
+unlink file cb = mkEff $ \_ -> runFn2
   fs.unlink file (handleCallback cb)
 
 -- |
@@ -206,7 +212,7 @@ rmdir :: forall eff. FilePath
                    -> Callback eff Unit
                    -> Eff (fs :: FS | eff) Unit
 
-rmdir file cb = return $ runFn2
+rmdir file cb = mkEff $ \_ -> runFn2
   fs.rmdir file (handleCallback cb)
 
 -- |
@@ -226,7 +232,7 @@ mkdir' :: forall eff. FilePath
                    -> Callback eff Unit
                    -> Eff (fs :: FS | eff) Unit
 
-mkdir' file mode cb = return $ runFn3
+mkdir' file mode cb = mkEff $ \_ -> runFn3
   fs.mkdir file mode (handleCallback cb)
 
 -- |
@@ -236,7 +242,7 @@ readdir :: forall eff. FilePath
                     -> Callback eff [FilePath]
                     -> Eff (fs :: FS | eff) Unit
 
-readdir file cb = return $ runFn2
+readdir file cb = mkEff $ \_ -> runFn2
   fs.readdir file (handleCallback cb)
 
 -- |
@@ -248,7 +254,7 @@ utimes :: forall eff. FilePath
                    -> Callback eff Unit
                    -> Eff (fs :: FS | eff) Unit
 
-utimes file atime mtime cb = return $ runFn4
+utimes file atime mtime cb = mkEff $ \_ -> runFn4
   fs.utimes file
             ((toEpochMilliseconds atime) / 1000)
             ((toEpochMilliseconds mtime) / 1000)
@@ -261,7 +267,7 @@ readFile :: forall eff. FilePath
                      -> Callback eff Buffer
                      -> Eff (fs :: FS | eff) Unit
 
-readFile file cb = return $ runFn3
+readFile file cb = mkEff $ \_ -> runFn3
   fs.readFile file {} (handleCallback cb)
 
 -- |
@@ -272,7 +278,7 @@ readTextFile :: forall eff. Encoding
                          -> Callback eff String
                          -> Eff (fs :: FS | eff) Unit
 
-readTextFile encoding file cb = return $ runFn3
+readTextFile encoding file cb = mkEff $ \_ -> runFn3
   fs.readFile file { encoding: show encoding } (handleCallback cb)
 
 -- |
@@ -283,7 +289,7 @@ writeFile :: forall eff. FilePath
                       -> Callback eff Unit
                       -> Eff (fs :: FS | eff) Unit
 
-writeFile file buff cb = return $ runFn4
+writeFile file buff cb = mkEff $ \_ -> runFn4
   fs.writeFile file buff {} (handleCallback cb)
 
 -- |
@@ -295,7 +301,7 @@ writeTextFile :: forall eff. Encoding
                           -> Callback eff Unit
                           -> Eff (fs :: FS | eff) Unit
 
-writeTextFile encoding file buff cb = return $ runFn4
+writeTextFile encoding file buff cb = mkEff $ \_ -> runFn4
   fs.writeFile file buff { encoding: show encoding } (handleCallback cb)
 
 -- |
@@ -306,7 +312,7 @@ appendFile :: forall eff. FilePath
                        -> Callback eff Unit
                        -> Eff (fs :: FS | eff) Unit
 
-appendFile file buff cb = return $ runFn4
+appendFile file buff cb = mkEff $ \_ -> runFn4
   fs.appendFile file buff {} (handleCallback cb)
 
 -- |
@@ -318,5 +324,5 @@ appendTextFile :: forall eff. Encoding
                            -> Callback eff Unit
                            -> Eff (fs :: FS | eff) Unit
 
-appendTextFile encoding file buff cb = return $ runFn4
+appendTextFile encoding file buff cb = mkEff $ \_ -> runFn4
   fs.appendFile file buff { encoding: show encoding } (handleCallback cb)