1 files changed, 13 insertions, 8 deletions
diff --git a/lambda-calcul/haskell/src/Minilang/REPL/Pure.hs b/lambda-calcul/haskell/src/Minilang/REPL/Pure.hs
index 8250152..d9dbbbe 100644
--- a/lambda-calcul/haskell/src/Minilang/REPL/Pure.hs
+++ b/lambda-calcul/haskell/src/Minilang/REPL/Pure.hs
@@ -13,9 +13,9 @@ import qualified Minilang.Lambda.Unify as Type
 import Minilang.REPL.Types
 
 data PureEnv = PureEnv
-  { inputText :: [Text],
-    outputText :: [Text],
-    pureREPL :: REPLEnv
+  { inputText :: [Text]
+  , outputText :: [Text]
+  , pureREPL :: REPLEnv
   }
 
 newtype PureREPL a = PureREPL {runPure :: CatchT (State PureEnv) a}
@@ -26,25 +26,30 @@ instance MonadREPL PureREPL where
     ins <- gets inputText
     case ins of
       [] -> pure EOF
-      (t : ts) -> modify (\e -> e {inputText = ts}) >> pure (interpret t)
+      (t : ts) -> modify (\e -> e{inputText = ts}) >> pure (interpret t)
 
-  output t = modify $ \e -> e {outputText = render t : outputText e}
+  output t = modify $ \e -> e{outputText = render t : outputText e}
 
   prompt = pure ()
 
   getEnv = gets pureREPL
 
-  setEnv e' = modify $ \e -> e {pureREPL = e'}
+  setEnv e' = modify $ \e -> e{pureREPL = e'}
 
   load f = pure $ Left $ REPLError $ "cannot load file " <> f <> " in Pure interpreter"
 
 render :: Out -> Text
 render = \case
   Msg t -> t
-  Evaluated ast _term typ -> pretty ast <> " : " <> Type.pretty typ
-  Defined ident typ -> ident <> " : " <> Type.pretty typ
+  Evaluated ast _term typ -> pretty ast <> renderType typ
+  Defined ident typ -> ident <> renderType typ
   Bye -> "Bye!"
   other -> pack (show other)
 
+renderType :: Maybe Type.Type -> Text
+renderType typ = case typ of
+  Nothing -> ""
+  Just t -> " : " <> Type.pretty t
+
 instance MonadThrow PureREPL where
   throwM = throw