Add Read instances

src/Picture/Data.hs

@@ -1,9 +1,11 @@
+{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE StrictData #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Picture.Data
     where
 import Geometry.Data
 
+import GHC.Generics
 import Control.Lens
 import Streaming
 data Verx = Verx
@@ -13,8 +15,7 @@ data Verx = Verx
     , _vxLayer  :: !Layer
     , _vxShadNum  :: !ShadNum
     }
-  deriving (Eq,Ord,Show)
---newtype LayNum  = LayNum  { _unLayNum :: Int }
+  deriving (Eq,Ord,Show,Generic,Read)
 
 data Layer
     = BottomLayer
@@ -23,7 +24,7 @@ data Layer
     | BloomNoZWrite
     | DebugLayer
     | FixedCoordLayer
-  deriving (Eq,Ord,Enum,Bounded,Show)
+  deriving (Eq,Ord,Enum,Bounded,Show,Generic,Read)
 
 layerNum :: Layer -> Int
 layerNum = fromEnum
@@ -31,7 +32,7 @@ numLayers :: Int
 numLayers = length [minBound::Layer .. maxBound]
 --TODO use synonyms for layer numbers
 newtype ShadNum = ShadNum { _unShadNum :: Int }
-  deriving (Eq,Ord,Show)
+  deriving (Eq,Ord,Show,Generic,Read)
 polyNum, polyzNum, bezNum, textNum, arcNum, ellNum :: ShadNum
 {-# INLINE polyNum #-}
 {-# INLINE polyzNum #-}