diff --git a/src/abstract_tree/map_node.rs b/src/abstract_tree/map_node.rs
index d32b5f3..71fd221 100644
--- a/src/abstract_tree/map_node.rs
+++ b/src/abstract_tree/map_node.rs
@@ -80,6 +80,12 @@ impl AbstractTree for MapNode {
     fn run(&self, _source: &str, _context: &Context) -> Result<Value, RuntimeError> {
         let mut map = Map::new();
 
+        for (key, (statement, _)) in &self.properties {
+            let value = statement.run(_source, _context)?;
+
+            map.set(key.clone(), value);
+        }
+
         Ok(Value::Map(map))
     }
 }
diff --git a/tests/value.rs b/tests/value.rs
index 8ec6ef0..5789a9b 100644
--- a/tests/value.rs
+++ b/tests/value.rs
@@ -144,13 +144,6 @@ fn function() {
     assert_eq!(&Type::Boolean, function.return_type());
 }
 
-#[test]
-fn option() {
-    let result = interpret("x <option(int)> = some(1); x").unwrap();
-
-    assert_eq!(Value::Option(Some(Box::new(Value::Integer(1)))), result);
-}
-
 #[test]
 fn range() {
     assert_eq!(interpret("0..100"), Ok(Value::range(0, 100)));