🚀 Functions

a1/src/APL/Eval_Tests.hs

@@ -7,28 +7,28 @@ import Test.Tasty.HUnit (testCase, (@?=))
 
 -- -- Consider this example when you have added the necessary constructors.
 -- -- The Y combinator in a form suitable for strict evaluation.
--- yComb :: Exp
--- yComb =
---   Lambda "f" $
---     Apply
---       (Lambda "g" (Apply (Var "g") (Var "g")))
---       ( Lambda
---           "g"
---           ( Apply
---               (Var "f")
---               (Lambda "a" (Apply (Apply (Var "g") (Var "g")) (Var "a")))
---           )
---       )
+yComb :: Exp
+yComb =
+  Lambda "f" $
+    Apply
+      (Lambda "g" (Apply (Var "g") (Var "g")))
+      ( Lambda
+          "g"
+          ( Apply
+              (Var "f")
+              (Lambda "a" (Apply (Apply (Var "g") (Var "g")) (Var "a")))
+          )
+      )
 
--- fact :: Exp
--- fact =
---   Apply yComb $
---     Lambda "rec" $
---       Lambda "n" $
---         If
---           (Eql (Var "n") (CstInt 0))
---           (CstInt 1)
---           (Mul (Var "n") (Apply (Var "rec") (Sub (Var "n") (CstInt 1))))
+fact :: Exp
+fact =
+  Apply yComb $
+    Lambda "rec" $
+      Lambda "n" $
+        If
+          (Eql (Var "n") (CstInt 0))
+          (CstInt 1)
+          (Mul (Var "n") (Apply (Var "rec") (Sub (Var "n") (CstInt 1))))
 
 tests :: TestTree
 tests =
@@ -90,7 +90,17 @@ tests =
               (Add (CstInt 2) (CstInt 3))
               (Let "x" (CstBool True) (Var "x"))
           )
-          @?= Right (ValBool True)
-          --
-          -- TODO - add more
+          @?= Right (ValBool True),
+      testCase "Lambda" $
+        eval
+          envEmpty
+          (
+            Lambda "y" (Var "y")
+          )
+          @?= Right (ValFun [] "y" (Var "y")),
+      testCase "Apply" $
+        eval [] (Apply (Let "x" (CstInt 2) (Lambda "y" (Add (Var "x") (Var "y")))) (CstInt 3))
+        @?= Right (ValInt 5),
+      testCase "Apply (fact)" $
+        eval envEmpty (Apply fact (CstInt 5)) @?= Right (ValInt 120)
     ]