1 files changed, 9 insertions, 0 deletions
diff --git a/src/lang/util.clj b/src/lang/util.clj
index d9745e9ab..ec93ac27f 100644
--- a/src/lang/util.clj
+++ b/src/lang/util.clj
@@ -112,3 +112,12 @@
 (def get-state
   (fn [state]
     (return* state state)))
+
+(defn within [slot monad]
+  (fn [state]
+    (let [=return (monad (get state slot))]
+      (match =return
+        [::ok [?state ?value]]
+        [::ok [(assoc state slot ?state) ?value]]
+        _
+        =return))))