Use Paths_ihaskell provided by cabal to get IHaskell version number

main/Main.hs

@@ -28,6 +28,7 @@ import           System.Posix.Signals
 import qualified Data.Map as Map
 import qualified Data.Text.Encoding as E
 import           Data.List (break, last)
+import           Data.Version (showVersion)
 
 -- IHaskell imports.
 import           IHaskell.Convert (convert)
@@ -46,6 +47,9 @@ import           IHaskell.IPython.Types
 import qualified IHaskell.IPython.Message.UUID as UUID
 import qualified IHaskell.IPython.Stdin as Stdin
 
+-- Cabal imports.
+import           Paths_ihaskell(version)
+
 -- GHC API imports.
 import           GHC hiding (extensions, language)
 
@@ -86,7 +90,7 @@ showDefault :: String -> [Argument] -> IO ()
 showDefault helpStr flags =
   case find (== Version) flags of
   Just _ ->
-    putStrLn VERSION_ipython_kernel
+    putStrLn (showVersion version)
   Nothing ->
     putStrLn helpStr
 
@@ -248,9 +252,9 @@ replyTo _ KernelInfoRequest{} replyHeader state =
     (state, KernelInfoReply
               { header = replyHeader
               , protocolVersion = "5.0"
-              , banner = "IHaskell " ++ VERSION_ipython_kernel ++ " GHC " ++ VERSION_ghc
+              , banner = "IHaskell " ++ (showVersion version) ++ " GHC " ++ VERSION_ghc
               , implementation = "IHaskell"
-              , implementationVersion = VERSION_ipython_kernel
+              , implementationVersion = showVersion version
               , languageInfo = LanguageInfo
                 { languageName = "haskell"
                 , languageVersion = VERSION_ghc