Added demo program.

examples/demo.cpp

@@ -0,0 +1,35 @@
+#include "settable.hpp"
+
+#include <iostream>
+
+#include <boost/lexical_cast.hpp>
+
+namespace settable {
+    namespace setter {
+        namespace string2type {
+            namespace helper {
+                template<>
+                int convert<int>(const std::string &value) {
+                    return boost::lexical_cast<int>(value);
+                }
+            }
+        }
+    }
+}
+
+struct foo : settable::settable {
+    foo() {
+        register_setter<int>("x", &x);
+    }
+
+    int x;
+};
+
+int main(int argc, char *argv) {
+    foo f;
+    f.set_attribute("x", "42");
+
+    std::cout << f.x << std::endl;
+
+    return 0;
+}