diff --git a/bower.json b/bower.json
index 39e9ff3..8a0687e 100644
--- a/bower.json
+++ b/bower.json
@@ -19,6 +19,7 @@
     "purescript-prelude": "^4.0.0"
   },
   "devDependencies": {
-    "purescript-effect": "^2.0.0"
+    "purescript-effect": "^2.0.0",
+    "purescript-exceptions": "^4.0.0"
   }
 }
diff --git a/src/Debug/Todo.js b/src/Debug/Todo.js
new file mode 100644
index 0000000..65a2a01
--- /dev/null
+++ b/src/Debug/Todo.js
@@ -0,0 +1,9 @@
+"use strict";
+
+// module Todo
+
+exports.crashWith = function () {
+  return function (msg) {
+    throw new Error(msg);
+  };
+};
diff --git a/src/Debug/Todo.purs b/src/Debug/Todo.purs
new file mode 100644
index 0000000..7c13d9d
--- /dev/null
+++ b/src/Debug/Todo.purs
@@ -0,0 +1,18 @@
+module Debug.Todo
+( notImplementedYet
+, (???)
+, todo
+) where
+
+import Data.Symbol (class IsSymbol, SProxy, reflectSymbol)
+import Prim.TypeError (class Warn, Beside, Text)
+
+notImplementedYet :: forall a. Warn (Text "not implemented yet") => a
+notImplementedYet = crashWith "not implemented yet"
+
+infix 5 notImplementedYet as ???
+
+todo :: forall a s. IsSymbol s => Warn (Beside (Text "TODO: ") (Text s)) => SProxy s -> a
+todo s = crashWith (reflectSymbol s)
+
+foreign import crashWith :: forall a. String -> a
diff --git a/test/Main.purs b/test/Main.purs
index b2562d7..bec260f 100644
--- a/test/Main.purs
+++ b/test/Main.purs
@@ -1,8 +1,11 @@
 module Test.Main where
 
+import Debug.Todo
 import Prelude
+
 import Debug.Trace (spy, trace, traceM)
 import Effect (Effect)
+import Effect.Exception (try)
 
 main :: Effect Unit
 main = do
@@ -25,6 +28,9 @@ main = do
   let dummy = spy "dummy" { foo: 1, bar: [1, 2] }
   traceM dummy
 
+  result :: _ String <- try (pure unit >>= \_ -> (???))
+  traceM (show result)
+
   where
   effInt :: Effect Int
   effInt = pure 0