Add more tests and references

4 files changed, 24 insertions, 8 deletions

diff --git a/lambda-calcul/README.md b/lambda-calcul/README.md
index e24a326..c37f51d 100644
--- a/lambda-calcul/README.md
+++ b/lambda-calcul/README.md
@@ -1,2 +1,3 @@
 * [on ruliology and λ-calcul](https://writings.stephenwolfram.com/2025/09/the-ruliology-of-lambdas/)
 * [typechecker zoo](https://www.stephendiehl.com/posts/typechecker_zoo/)
+* [A tale of 4 lambdas](https://raw.githubusercontent.com/steshaw/lennart-lambda/master/top.pdf)
diff --git a/lambda-calcul/haskell/test/Minilang/IOSpec.hs b/lambda-calcul/haskell/test/Minilang/IOSpec.hs
index c4ae13e..14d279d 100644
--- a/lambda-calcul/haskell/test/Minilang/IOSpec.hs
+++ b/lambda-calcul/haskell/test/Minilang/IOSpec.hs
@@ -16,7 +16,7 @@ spec = parallel $
       it "evaluates a simple MiniLang 'program' and dumps result" $ \fileName -> do
         let outputFileName = fileName <> ".out"
             program =
-              [ "((lam (x) x) y)"
+              [ "((lam (x y) x) z t)"
               ]
 
         writeFile fileName (unlines program)
@@ -27,7 +27,7 @@ spec = parallel $
 
         out <- readFile outputFileName
 
-        out `shouldBe` "Var \"y\"\n"
+        out `shouldBe` "Var \"z\"\n"
 
 withTempFile :: (String -> IO ()) -> IO ()
 withTempFile =
diff --git a/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs b/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
index df933a4..11cf394 100644
--- a/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
+++ b/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
@@ -7,9 +7,16 @@ import Test.Hspec (Spec, describe, it, shouldBe)
 
 spec :: Spec
 spec = do
-  let fix = Lam "x" (App (Var "x") (Var "x"))
+  let fix =
+        Lam
+          "f"
+          ( App
+              (Lam "x" (App (Var "f") (App (Var "x") (Var "x"))))
+              (Lam "x" (App (Var "f") (App (Var "x") (Var "x"))))
+          )
   let omega = App fix fix
   let term = App (App (Lam "x" (Lam "y" (Var "y"))) omega) (Var "z")
+  let fst' = Lam "x" (Lam "y" (Var "x"))
 
   describe "call-by-value eval" $ do
     it "evaluates 'x' as itself" $ do
@@ -18,12 +25,16 @@ spec = do
     it "evaluates '((λ x. x) y)' as 'y'" $ do
       let term = App (Lam "x" (Var "x")) (Var "y")
       eval term [] `shouldBe` Var "y"
-    it "evaluates '((λ x y. y) y z t)' as '(z t)'" $ do
+    it "evaluates '((λ x y. y) z t y)' as '(t y)'" $ do
       let snd' = Lam "x" (Lam "y" (Var "y"))
-      let term = App (App (App snd' (Var "y")) (Var "z")) (Var "t")
-      eval term [] `shouldBe` App (Var "z") (Var "t")
+      let term = App (App (App snd' (Var "z")) (Var "t")) (Var "y")
+      eval term [] `shouldBe` App (Var "t") (Var "y")
+    it "evaluates '((λ x y. x) z t)' as 'z'" $ do
+      let term = App (App fst' (Var "z")) (Var "t")
+      eval term [] `shouldBe` Var "z"
     it "diverges on evaluating argument bound to ω" $
-      shouldDiverge $ eval term []
+      shouldDiverge $
+        eval term []
 
   describe "call-by-need eval" $ do
     it "evaluates 'x' as itself" $ do
@@ -31,7 +42,8 @@ spec = do
     it "evaluates '(λ x y . y) ⊥ z' as 'z'" $ do
       evalNeed term [] `shouldBe` Var "z"
     it "diverges on evaluating ω" $
-      shouldDiverge $ evalNeed omega []
+      shouldDiverge $
+        evalNeed omega []
 
 shouldDiverge :: Term -> IO ()
 shouldDiverge t =
diff --git a/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs b/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
index d4c90bd..5d3e8ab 100644
--- a/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
+++ b/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
@@ -13,6 +13,9 @@ import Test.Hspec (Spec, parallel, shouldBe)
 import Test.Hspec.QuickCheck (prop)
 import Test.QuickCheck (Arbitrary (..), Gen, NonEmptyList (..), counterexample, elements, forAll, forAllShrink, listOf, oneof, resize, sized, (===), (==>))
 
+-- ((f x) y) --> (f x y)
+-- (lam (x) (lam (y) y)) --> (lam (x y) y)
+
 spec :: Spec
 spec = parallel $ do
   prop "parses an identifier as a variable" $ \(Identifier ident) ->