diff --git a/example/ex1/ex1.cpp b/example/ex1/ex1.cpp
index 19dddc82..5c12a4b1 100644
--- a/example/ex1/ex1.cpp
+++ b/example/ex1/ex1.cpp
@@ -1,14 +1,34 @@
 /** @file ex1.cpp **/
 
 #include "xo/expression/Constant.hpp"
+#include "xo/expression/Primitive.hpp"
 #include <iostream>
+#include <cmath>
 
 int
 main() {
     using xo::ast::make_constant;
+    using xo::ast::make_primitive;
+    using std::cout;
+    using std::endl;
 
-    auto expr = make_constant(7);
+    {
+        auto expr = make_constant(7);
+    }
+
+    {
+        auto expr = make_primitive("sqrt", &::sqrt);
+
+        auto expr_td = expr->value_td();
+
+        cout << "expr_td: " << expr_td->short_name() << endl;
+        cout << "expr_td->is_function(): " << expr_td->is_function() << endl;
+        cout << "expr_td->fn_retval(): " << expr_td->fn_retval()->short_name() << endl;
+        cout << "expr_td->n_fn_arg(): " << expr_td->n_fn_arg() << endl;
+        for (uint32_t i = 0; i < expr_td->n_fn_arg(); ++i)
+            cout << "expr_td->fn_arg(" << i << "): " << expr_td->fn_arg(i)->short_name() << endl;
+        cout << "expr_td->fn_is_noexcept(): " << expr_td->fn_is_noexcept() << endl;
+    }
 }
 
-
 /** end ex1.cpp **/