From 99e2ce71faa82e7b99574895e0fe24183ba9f6c3 Mon Sep 17 00:00:00 2001
From: Arnaud Bailly <arnaud@pankzsoft.com>
Date: Wed, 5 Nov 2025 12:02:23 +0100
Subject: can parse whole programs and load them

---
 lambda-calcul/haskell/src/Minilang/Lambda.hs | 69 ++++++++++++++++++++--------
 1 file changed, 49 insertions(+), 20 deletions(-)

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

diff --git a/lambda-calcul/haskell/src/Minilang/Lambda.hs b/lambda-calcul/haskell/src/Minilang/Lambda.hs
index d2df56f..2372578 100644
--- a/lambda-calcul/haskell/src/Minilang/Lambda.hs
+++ b/lambda-calcul/haskell/src/Minilang/Lambda.hs
@@ -1,32 +1,61 @@
 module Minilang.Lambda where
 
-import Minilang.Lambda.DeBruijn (eval, fromDeBruijn, toDeBruijn)
+import Data.Bifunctor (second)
+import Minilang.Lambda.DeBruijn (eval, eval', fromDeBruijn, toDeBruijn)
 import Minilang.Lambda.Eval (Env, Term)
 import Minilang.Lambda.Infer (Context, TypeError, infer)
-import Minilang.Lambda.Parser (AST, desugar)
+import Minilang.Lambda.Parser (AST (..), desugar)
 import Minilang.Lambda.Unify (Type (..))
 import Minilang.REPL.Types (Language (..))
 
 -- | Top-level evaluator
--- Load an AST into given `Env` and `Context`, returning an extended
--- `Env` and `Context` with declarations bound
+-- Load a list of expressions into given `Env` and `Context`, returning an extended
+-- `Env` and `Context` with declarations bound and the list of evaluated top-level
+-- terms along with their types.
 loadProgram ::
   Language ->
-  AST ->
   Env ->
   Context ->
-  Either TypeError (Term, Type, Env, Context)
--- loadProgram (Let d r) ρ γ = do
---   (ρ', γ') <- checkD 0 d ρ γ
---   loadProgram r ρ' γ'
-loadProgram language expr env context =
-  let term = desugar expr
-      v = fromDeBruijn $ eval (toDeBruijn term)
-   in case language of
-        Typed ->
-          case infer term of
-            Left typeError -> Left typeError
-            Right typ ->
-              Right (v, typ, env, context)
-        Untyped ->
-          Right (v, TyVar "<?>", env, context)
+  [AST] ->
+  Either TypeError ([(Term, Type)], Env, Context)
+loadProgram language env context exprs =
+  fmap (\(res, e, c) -> (reverse res, e, c)) result
+  where
+    result =
+      foldr
+        ( \expr acc ->
+            case acc of
+              Left typeError -> Left typeError
+              Right (results, env', context') ->
+                case runExpr language expr env' context' of
+                  Left typeError -> Left typeError
+                  Right (Nothing, env'', context'') ->
+                    Right (results, env'', context'')
+                  Right (Just res, env'', context'') ->
+                    Right (res : results, env'', context'')
+        )
+        (Right ([], env, context))
+        exprs
+
+    runExpr language (Def ident body) env context =
+      let term = desugar body
+       in case language of
+            Typed ->
+              case infer term of
+                Left typeError -> Left typeError
+                Right typ ->
+                  Right (Nothing, (ident, term) : env, context)
+            Untyped ->
+              Right (Nothing, (ident, term) : env, context)
+    runExpr language expr env context =
+      let term = desugar expr
+          env' = second toDeBruijn <$> env
+          v = fromDeBruijn $ eval' env' (toDeBruijn term)
+       in case language of
+            Typed ->
+              case infer term of
+                Left typeError -> Left typeError
+                Right typ ->
+                  Right (Just (v, typ), env, context)
+            Untyped ->
+              Right (Just (v, TyVar "<?>"), env, context)
-- 
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