@@ -45,10 +45,22 @@
 	/*! Both objects are equal */
 	OF_ORDERED_SAME = 0,
 	/*! The left object is bigger than the right */
 	OF_ORDERED_DESCENDING = 1
 } of_comparison_result_t;
+
+#ifdef OF_HAVE_BLOCKS
+/*!
+ * @brief A comparator to compare two objects.
+ *
+ * @param left The left object
+ * @param right The right object
+ * @return The order of the objects
+ */
+typedef of_comparison_result_t (^of_comparator_t)(id _Nonnull left,
+    id _Nonnull right);
+#endif
 
 /*!
  * @brief An enum for storing endianess.
  */
 typedef enum {