pretty: Print arguments of open expression

1 files changed, 12 insertions, 3 deletions

diff --git a/src/AST/Pretty.hs b/src/AST/Pretty.hs
index 604133b..da4f391 100644
--- a/src/AST/Pretty.hs
+++ b/src/AST/Pretty.hs
@@ -10,8 +10,9 @@
 module AST.Pretty (pprintExpr, ppExpr, ppSTy, ppTy, PrettyX(..)) where
 
 import Control.Monad (ap)
-import Data.List (intersperse)
+import Data.List (intersperse, intercalate)
 import Data.Functor.Const
+import qualified Data.Functor.Product as Product
 import Data.String (fromString)
 import Prettyprinter
 import Prettyprinter.Render.String
@@ -67,8 +68,16 @@ genNameIfUsedIn = genNameIfUsedIn' "x"
 pprintExpr :: (KnownEnv env, PrettyX x) => Expr x env t -> IO ()
 pprintExpr = putStrLn . ppExpr knownEnv
 
-ppExpr :: PrettyX x => SList f env -> Expr x env t -> String
-ppExpr senv e = render $ fst (runM (mkVal senv >>= \val -> ppExpr' 0 val e) 1)
+ppExpr :: PrettyX x => SList STy env -> Expr x env t -> String
+ppExpr senv e = render $ fst . flip runM 1 $ do
+  val <- mkVal senv
+  e' <- ppExpr' 0 val e
+  let lam = "λ" ++ intercalate " " (reverse (unSList (\(Product.Pair (Const name) ty) -> "(" ++ name ++ " : " ++ ppSTy 0 ty ++ ")") (slistZip val senv))) ++ "."
+  return $ group $ flatAlt
+    (hang 2 $
+       ppString lam
+       <> hardline <> e')
+    (ppString lam <+> e')
   where
     mkVal :: SList f env -> M (SVal env)
     mkVal SNil = return SNil