From ae59f17cb3d58de7afca7f441d8bcf9a718e024c Mon Sep 17 00:00:00 2001
From: Arnaud Bailly <arnaud@pankzsoft.com>
Date: Wed, 5 Nov 2025 09:15:46 +0100
Subject: handle defitions in untyped language

---
 lambda-calcul/haskell/src/Minilang/REPL/Run.hs | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

(limited to 'lambda-calcul/haskell/src/Minilang/REPL/Run.hs')

diff --git a/lambda-calcul/haskell/src/Minilang/REPL/Run.hs b/lambda-calcul/haskell/src/Minilang/REPL/Run.hs
index bc552cb..a98ff41 100644
--- a/lambda-calcul/haskell/src/Minilang/REPL/Run.hs
+++ b/lambda-calcul/haskell/src/Minilang/REPL/Run.hs
@@ -7,13 +7,14 @@
 module Minilang.REPL.Run where
 
 import Control.Monad.Catch
+import Data.Bifunctor (second)
 import Data.Text hiding (replicate)
 import Minilang.Lambda (loadProgram)
-import Minilang.Lambda.DeBruijn (eval, fromDeBruijn, toDeBruijn)
+import Minilang.Lambda.DeBruijn (eval, eval', fromDeBruijn, toDeBruijn)
 import Minilang.Lambda.Eval (newEnv)
 import Minilang.Lambda.Infer (infer, newContext)
 import qualified Minilang.Lambda.Infer as Infer
-import Minilang.Lambda.Parser (desugar, parse, resugar)
+import Minilang.Lambda.Parser (AST (..), desugar, parse, resugar)
 import Minilang.Lambda.Unify (Type (TyVar))
 import Minilang.REPL.Types
 
@@ -35,12 +36,25 @@ handleUserInput ::
   Text ->
   m ()
 handleUserInput txt = do
-  REPLEnv {language} <- getEnv
+  repl@REPLEnv {language, env} <- getEnv
   case parse txt of
     Left err -> output (Msg $ pack $ show err)
+    Right (Def ident body) -> do
+      let term = desugar body
+      case language of
+        Typed ->
+          case infer term of
+            Left typeError -> output (Msg $ Infer.render typeError)
+            Right typ -> do
+              setEnv $ repl {env = (ident, term) : env}
+              output (Defined ident typ)
+        Untyped -> do
+          setEnv $ repl {env = (ident, term) : env}
+          output (Defined ident (TyVar "<?>"))
     Right expr -> do
       let term = desugar expr
-          v = fromDeBruijn $ eval (toDeBruijn term)
+          env' = second toDeBruijn <$> env
+          v = fromDeBruijn $ eval' env' (toDeBruijn term)
           ast = resugar v
       case language of
         Typed ->
-- 
cgit v1.3.1