1 files changed, 6 insertions, 0 deletions
diff --git a/build/rule-map b/build/rule-map
index 0ef0036..0ce49e7 100644
--- a/build/rule-map
+++ b/build/rule-map
@@ -52,6 +52,9 @@ namespace build
       return map_.size () > oid ? &map_[oid] : nullptr;
     }
 
+    bool
+    empty () const {return map_.empty ();}
+
   private:
     std::vector<target_type_rule_map> map_;
   };
@@ -92,6 +95,9 @@ namespace build
     explicit
     rule_map (meta_operation_id mid = perform_id): mid_ (mid) {}
 
+    bool
+    empty () const {return map_.empty () && next_ == nullptr;}
+
   private:
     meta_operation_id mid_;
     operation_rule_map map_;