1 files changed, 18 insertions, 0 deletions
diff --git a/src/lib/util.rs b/src/lib/util.rs
index 72844d5f..f6e1327b 100644
--- a/src/lib/util.rs
+++ b/src/lib/util.rs
@@ -1,3 +1,21 @@
+tag option[T] {
+    none;
+    some(T);
+}
+
+type operator[T, U] = fn(&T) -> U;
+
+fn option_map[T, U](&operator[T, U] f, &option[T] opt) -> option[U] {
+    alt (opt) {
+        case (some[T](?x)) {
+            ret some[U](f(x));
+        }
+        case (none[T]) {
+            ret none[U];
+        }
+    }
+}
+
 fn id[T](&T x) -> T {
     ret x;
 }