More fixes.

tensorflow-queue/tests/QueueTest.hs

@@ -20,9 +20,8 @@ module Main where
 
 import Control.Monad.IO.Class (liftIO)
 import Data.Int (Int64)
-import Data.Functor.Identity (Identity(..))
 import Google.Test (googleTest)
-import TensorFlow.Types (ListOf(..), Scalar(..))
+import TensorFlow.Types (ListOf(..), Scalar(..), (|:|))
 import TensorFlow.Ops (scalar)
 import TensorFlow.Queue
 import TensorFlow.Session
@@ -44,11 +43,16 @@ testBasic = testCase "testBasic" $ runSession $ do
     q :: Queue [Int64, BS.ByteString] <- build $ makeQueue 1 ""
     buildAnd run_ $ enqueue q $ 42 :| scalar "Hi" :| Nil
     x <- buildAnd run (dequeue q)
-    liftIO $ (Identity (Scalar 42) :| Identity (Scalar "Hi") :| Nil) @=? x
+    liftIO $ (Scalar 42 |:| Scalar "Hi" |:| Nil) @=? x
 
     buildAnd run_ $ enqueue q $ 56 :| scalar "Bar" :| Nil
     y <- buildAnd run (dequeue q)
-    let expected = Identity (Scalar 56) :| Identity (Scalar "Bar") :| Nil
+    -- Note: we use explicit "Scalar" here to specify the type that was
+    -- fetched.  Equivalently we could write
+    -- 56 |:| "Bar" |:| Nil :: List [Scalar Int64, Scalar BS.ByteString]
+    -- or else allow the types to be determined by future use of the fetched
+    -- value.
+    let expected = Scalar 56 |:| Scalar "Bar" |:| Nil
     liftIO $ expected @=? y
 
 -- | Test queue pumping.
@@ -64,7 +68,7 @@ testPump = testCase "testPump" $ runSession $ do
     run_ (pump, pump)
 
     (x, y) <- run (deq, deq)
-    let expected = Identity (Scalar 31) :| Identity (Scalar "Baz") :| Nil
+    let expected = Scalar 31 |:| Scalar "Baz" |:| Nil
     liftIO $ expected @=? x
     liftIO $ expected @=? y
 
@@ -77,7 +81,7 @@ testAsync = testCase "testAsync" $ runSession $ do
     -- Pumps the queue until canceled by runSession exiting.
     asyncProdNodes pump
     -- Picks up a couple values and verifies they are as expected.
-    let expected = Identity (Scalar 10) :| Identity (Scalar "Async") :| Nil
+    let expected = Scalar 10 |:| Scalar "Async" |:| Nil
     run deq >>= liftIO . (expected @=?)
     run deq >>= liftIO . (expected @=?)
 

tensorflow/src/TensorFlow/BuildOp.hs

@@ -30,7 +30,6 @@ import Control.Monad (replicateM)
 import Control.Monad.Reader (ReaderT, runReaderT, ask)
 import Control.Monad.State.Strict (State, runState, get, put)
 import Data.Int (Int64)
-import Data.Proxy (Proxy(..))
 import Lens.Family2 ((&), (<>~), (^.))
 
 import TensorFlow.Build

tensorflow/src/TensorFlow/Types.hs

@@ -42,6 +42,7 @@ module TensorFlow.Types
     -- * Lists
     , ListOf(..)
     , List
+    , (|:|)
     , TensorTypeProxy(..)
     , TensorTypes(..)
     , TensorTypeList
@@ -60,7 +61,7 @@ module TensorFlow.Types
     , AllTensorTypes
     ) where
 
-import Data.Functor.Identity (Identity)
+import Data.Functor.Identity (Identity(..))
 import Data.Complex (Complex)
 import Data.Default (def)
 import Data.Int (Int8, Int16, Int32, Int64)
@@ -421,6 +422,12 @@ instance All Show (Map f as) => Show (ListOf f as) where
 
 type List = ListOf Identity
 
+-- | Equivalent of ':|' for lists.
+(|:|) :: a -> List as -> List (a ': as)
+(|:|) = (:|) . Identity
+
+infixr 5 |:|
+
 -- | A 'Constraint' specifying the possible choices of a 'TensorType'.
 --
 -- We implement a 'Constraint' like @OneOf '[Double, Float] a@ by turning the