diff --git a/example/x3/calc/calc7/expression_def.hpp b/example/x3/calc/calc7/expression_def.hpp
index dc73c288ce..69fb947e05 100644
--- a/example/x3/calc/calc7/expression_def.hpp
+++ b/example/x3/calc/calc7/expression_def.hpp
@@ -64,7 +64,7 @@ namespace client
 {
     calculator_grammar::expression_type expression()
     {
-        return calculator_grammar::expression;
+        return {"expression"};
     }
 }
 
diff --git a/example/x3/calc/calc8/expression.hpp b/example/x3/calc/calc8/expression.hpp
index d619510cd7..528a6f9a6f 100644
--- a/example/x3/calc/calc8/expression.hpp
+++ b/example/x3/calc/calc8/expression.hpp
@@ -20,7 +20,7 @@ namespace client
         BOOST_SPIRIT_DECLARE(expression_type);
     }
     
-    parser::expression_type const& expression();
+    parser::expression_type expression();
 }
 
 #endif
diff --git a/example/x3/calc/calc8/expression_def.hpp b/example/x3/calc/calc8/expression_def.hpp
index fe9eaee98b..bd08f361af 100644
--- a/example/x3/calc/calc8/expression_def.hpp
+++ b/example/x3/calc/calc8/expression_def.hpp
@@ -82,9 +82,9 @@ namespace client { namespace parser
 
 namespace client
 {
-    parser::expression_type const& expression()
+    parser::expression_type expression()
     {
-        return parser::expression;
+        return {"expression"};
     }
 }
 
diff --git a/example/x3/calc/calc8/statement.hpp b/example/x3/calc/calc8/statement.hpp
index 7b8973d0da..ac6e58ec7c 100644
--- a/example/x3/calc/calc8/statement.hpp
+++ b/example/x3/calc/calc8/statement.hpp
@@ -20,7 +20,7 @@ namespace client
         BOOST_SPIRIT_DECLARE(statement_type);
     }
     
-    parser::statement_type const& statement();
+    parser::statement_type statement();
 }
 
 #endif
diff --git a/example/x3/calc/calc8/statement_def.hpp b/example/x3/calc/calc8/statement_def.hpp
index 8772c76fe3..c5f87bf961 100644
--- a/example/x3/calc/calc8/statement_def.hpp
+++ b/example/x3/calc/calc8/statement_def.hpp
@@ -39,7 +39,7 @@ namespace client { namespace parser
     variable_type const variable = "variable";
 
     // Import the expression rule
-    namespace { auto const& expression = client::expression(); }
+    namespace { auto expression = client::expression(); }
 
     auto const statement_list_def =
         +(variable_declaration | assignment)
@@ -75,7 +75,7 @@ namespace client { namespace parser
 
 namespace client
 {
-    parser::statement_type const& statement()
+    parser::statement_type statement()
     {
         return parser::statement;
     }
diff --git a/example/x3/calc/calc9/expression.hpp b/example/x3/calc/calc9/expression.hpp
index f9fa1cc3b2..07bede71ae 100644
--- a/example/x3/calc/calc9/expression.hpp
+++ b/example/x3/calc/calc9/expression.hpp
@@ -20,7 +20,7 @@ namespace client
         BOOST_SPIRIT_DECLARE(expression_type);
     }
     
-    parser::expression_type const& expression();
+    parser::expression_type expression();
 }
 
 #endif
diff --git a/example/x3/calc/calc9/expression_def.hpp b/example/x3/calc/calc9/expression_def.hpp
index 251fb840df..5556db5617 100644
--- a/example/x3/calc/calc9/expression_def.hpp
+++ b/example/x3/calc/calc9/expression_def.hpp
@@ -36,54 +36,55 @@ namespace client { namespace parser
     x3::symbols<ast::optoken> unary_op;
     x3::symbols<> keywords;
 
-    void add_keywords()
+    namespace
     {
-        static bool once = false;
-        if (once)
-            return;
-        once = true;
-
-        logical_op.add
-            ("&&", ast::op_and)
-            ("||", ast::op_or)
-            ;
-
-        equality_op.add
-            ("==", ast::op_equal)
-            ("!=", ast::op_not_equal)
-            ;
-
-        relational_op.add
-            ("<", ast::op_less)
-            ("<=", ast::op_less_equal)
-            (">", ast::op_greater)
-            (">=", ast::op_greater_equal)
-            ;
-
-        additive_op.add
-            ("+", ast::op_plus)
-            ("-", ast::op_minus)
-            ;
-
-        multiplicative_op.add
-            ("*", ast::op_times)
-            ("/", ast::op_divide)
-            ;
-
-        unary_op.add
-            ("+", ast::op_positive)
-            ("-", ast::op_negative)
-            ("!", ast::op_not)
-            ;
-
-        keywords.add
-            ("var")
-            ("true")
-            ("false")
-            ("if")
-            ("else")
-            ("while")
-            ;
+        struct add_keywords
+        {
+            add_keywords() {
+                logical_op.add
+                    ("&&", ast::op_and)
+                    ("||", ast::op_or)
+                    ;
+
+                equality_op.add
+                    ("==", ast::op_equal)
+                    ("!=", ast::op_not_equal)
+                    ;
+
+                relational_op.add
+                    ("<", ast::op_less)
+                    ("<=", ast::op_less_equal)
+                    (">", ast::op_greater)
+                    (">=", ast::op_greater_equal)
+                    ;
+
+                additive_op.add
+                    ("+", ast::op_plus)
+                    ("-", ast::op_minus)
+                    ;
+
+                multiplicative_op.add
+                    ("*", ast::op_times)
+                    ("/", ast::op_divide)
+                    ;
+
+                unary_op.add
+                    ("+", ast::op_positive)
+                    ("-", ast::op_negative)
+                    ("!", ast::op_not)
+                    ;
+
+                keywords.add
+                    ("var")
+                    ("true")
+                    ("false")
+                    ("if")
+                    ("else")
+                    ("while")
+                    ;
+            }
+            
+        } init_helper;
     }
 
     ////////////////////////////////////////////////////////////////////////////
@@ -172,10 +173,9 @@ namespace client { namespace parser
 
 namespace client
 {
-    parser::expression_type const& expression()
+    parser::expression_type expression()
     {
-        parser::add_keywords();
-        return parser::expression;
+        return {"expression"};
     }
 }
 
diff --git a/example/x3/calc/calc9/statement.hpp b/example/x3/calc/calc9/statement.hpp
index d0c3f514fc..e6a752016a 100644
--- a/example/x3/calc/calc9/statement.hpp
+++ b/example/x3/calc/calc9/statement.hpp
@@ -21,7 +21,7 @@ namespace client
         BOOST_SPIRIT_DECLARE(statement_type);
     }
     
-    parser::statement_type const& statement();
+    parser::statement_type statement();
 }
 
 #endif
diff --git a/example/x3/calc/calc9/statement_def.hpp b/example/x3/calc/calc9/statement_def.hpp
index 84355caa6f..f09f9ab6ef 100644
--- a/example/x3/calc/calc9/statement_def.hpp
+++ b/example/x3/calc/calc9/statement_def.hpp
@@ -39,7 +39,7 @@ namespace client { namespace parser
     variable_type const variable("variable");
 
     // Import the expression rule
-    namespace { auto const& expression = client::expression(); }
+    namespace { auto expression = client::expression(); }
 
     auto const statement_list_def =
         +(variable_declaration | assignment)
@@ -75,9 +75,10 @@ namespace client { namespace parser
 
 namespace client
 {
-    parser::statement_type const& statement()
+    parser::statement_type statement()
     {
-        return parser::statement;
+        //return parser::statement;
+        return {"statement"};
     }
 }