diff --git a/include/xo/parser/parser.hpp b/include/xo/parser/parser.hpp
index e4e8943a..deabaab8 100644
--- a/include/xo/parser/parser.hpp
+++ b/include/xo/parser/parser.hpp
@@ -327,6 +327,12 @@ namespace xo {
                 return exprstatetype::invalid;
             }
 
+            /** true iff parser contains state for an incomplete expression.
+             *  For this to be true,  parser must have consumed at least one token
+             *  since end of last toplevel expression
+             **/
+            bool has_incomplete_expr() const;
+
             /** put parser into state for beginning of a translation unit
              *  (i.e. input stream)
              **/
diff --git a/src/parser/parser.cpp b/src/parser/parser.cpp
index 8a60bbbd..71da1798 100644
--- a/src/parser/parser.cpp
+++ b/src/parser/parser.cpp
@@ -689,6 +689,11 @@ namespace xo {
 
         // ----- parser -----
 
+        bool
+        parser::has_incomplete_expr() const {
+            return !xs_stack_.empty();
+        }
+
         void
         parser::begin_translation_unit() {
             xs_stack_.push_exprstate