1 files changed, 8 insertions, 2 deletions

diff --git a/format.h b/format.h
index 7fc46985..c61518be 100644
--- a/format.h
+++ b/format.h
@@ -54,13 +54,19 @@ struct format_t
   static std::auto_ptr<node_t> value_expr;
   static std::auto_ptr<node_t> total_expr;
 
-  format_t(const std::string& _format) {
-    elements = parse_elements(_format);
+  format_t(const std::string& _format) : elements(NULL) {
+    reset(_format);
   }
   ~format_t() {
     if (elements) delete elements;
   }
 
+  void reset(const std::string& _format) {
+    if (elements)
+      delete elements;
+    elements = parse_elements(_format);
+  }
+
   static element_t * parse_elements(const std::string& fmt);
 
   void format_elements(std::ostream& out, const details_t& details) const;