diff --git a/a4/src/APL/InterpIO.hs b/a4/src/APL/InterpIO.hs
index 89c8d06..ba20de8 100644
--- a/a4/src/APL/InterpIO.hs
+++ b/a4/src/APL/InterpIO.hs
@@ -94,3 +94,8 @@ runEvalIO evalm = do
           runEvalIO' r db m
         Left e -> pure $ Left e
     runEvalIO' _ _ (Free (ErrorOp e)) = pure $ Left e
+    runEvalIO' r db (Free (TryCatchOp m1 m2)) = do
+      result <- runEvalIO' r db m1
+      case result of
+        Right x -> pure $ Right x
+        Left _ -> runEvalIO' r db m2
diff --git a/a4/src/APL/Interp_Tests.hs b/a4/src/APL/Interp_Tests.hs
index 0edcded..2d4d769 100644
--- a/a4/src/APL/Interp_Tests.hs
+++ b/a4/src/APL/Interp_Tests.hs
@@ -142,7 +142,23 @@ ioTests =
           getState
 
         r @?= Right [(ValInt 0, ValInt 5)],
-      --
+      ---
+      testCase "TryCatch try1" $ do
+        r <- evalIO' (TryCatch (CstInt 1) (CstInt 2))
+        r @?= Right (ValInt 1),
+      ---
+      testCase "TryCatch try2" $ do
+        r <- evalIO' (TryCatch (CstInt 1) (Div (CstInt 1) (CstInt 0)))
+        r @?= Right (ValInt 1),
+      ---
+      testCase "TryCatch catch1" $ do
+        r <- evalIO' (TryCatch (Div (CstInt 1) (CstInt 0)) (CstInt 1))
+        r @?= Right (ValInt 1),
+      ---
+      testCase "TryCatch catch2" $ do
+        r <- evalIO' (TryCatch (Div (CstInt 1) (CstInt 0)) (Div (CstInt 1) (CstInt 0)))
+        r @?= Left "Division by zero",
+      ---
       testCase "KvPutOp" $ do
         r <- evalIO' (KvPut (CstInt 1) (CstInt 2))
         r @?= Right (ValInt 2),