@@ -1,3 +1,4 @@
+packages: .
 ignore-project: False
 write-ghc-environment-files: always
 tests: True

@@ -30,14 +30,14 @@
 module ArrayFire.Data where
 
 import Control.Exception
-import Control.Monad
 import Data.Complex
 import Data.Int
 import Data.Proxy
 import Data.Word
 import Foreign.C.Types
 import Foreign.ForeignPtr
 import Foreign.Marshal hiding (void)
+import Foreign.Ptr (Ptr)
 import Foreign.Storable
 import System.IO.Unsafe
 import Unsafe.Coerce
@@ -357,20 +357,21 @@ joinMany
 :: Int
 -> [Array a]
 -> Array a
-joinMany (fromIntegral -> n) arrays = unsafePerformIO . mask_ $ do
-fptrs <- forM arrays $ \(Array fptr) -> pure fptr
-newPtr <-
-alloca $ \fPtrsPtr -> do
-forM_ fptrs $ \fptr ->
-withForeignPtr fptr (poke fPtrsPtr)
-alloca $ \aPtr -> do
-zeroOutArray aPtr
-throwAFError =<< af_join_many aPtr n nArrays fPtrsPtr
-peek aPtr
+joinMany (fromIntegral -> n) (fmap (\(Array fp) -> fp) -> arrays) = unsafePerformIO . mask_ $ do
+newPtr <- alloca $ \aPtr -> do
+zeroOutArray aPtr
+(throwAFError =<<) $
+withManyForeignPtr arrays $ \(fromIntegral -> nArrays) fPtrsPtr ->
+af_join_many aPtr n nArrays fPtrsPtr
+peek aPtr
 Array <$>
 newForeignPtr af_release_array_finalizer newPtr
+
+withManyForeignPtr :: [ForeignPtr a] -> (Int -> Ptr (Ptr a) -> IO b) -> IO b
+withManyForeignPtr fptrs action = go [] fptrs
 where
-nArrays = fromIntegral (length arrays)
+go ptrs [] = withArrayLen (reverse ptrs) action
+go ptrs (fptr:others) = withForeignPtr fptr $ \ptr -> go (ptr : ptrs) others
 
 -- | Tiles an Array according to specified dimensions
 --

@@ -32,3 +32,8 @@ spec =
 constant @(Complex Float) [1] (1.0 :+ 1.0)
 `shouldBe`
 constant @(Complex Float) [1] (1.0 :+ 1.0)
+it "Should join Arrays along the specified dimension" $ do
+join 0 (constant @Int [1, 3] 1) (constant @Int [1, 3] 2) `shouldBe` mkArray @Int [2, 3] [1, 2, 1, 2, 1, 2]
+join 1 (constant @Int [1, 2] 1) (constant @Int [1, 2] 2) `shouldBe` mkArray @Int [1, 4] [1, 1, 2, 2]
+joinMany 0 [constant @Int [1, 3] 1, constant @Int [1, 3] 2] `shouldBe` mkArray @Int [2, 3] [1, 2, 1, 2, 1, 2]
+joinMany 1 [constant @Int [1, 2] 1, constant @Int [1, 1] 2, constant @Int [1, 3] 3] `shouldBe` mkArray @Int [1, 6] [1, 1, 2, 3, 3, 3]