diff --git a/build/boost/doc/Jamfile.jam b/build/boost/doc/Jamfile.jam
index aa9762c..ab71f8d 100644
--- a/build/boost/doc/Jamfile.jam
+++ b/build/boost/doc/Jamfile.jam
@@ -50,3 +50,4 @@ compile example/customisation.cpp ;
 compile example/async_call.cpp ;
 compile example/retrieve_cref.cpp ;
 compile example/invoke_functor.cpp ;
+compile example/quick_constraint.cpp ;
diff --git a/build/boost/doc/example/quick_constraint.cpp b/build/boost/doc/example/quick_constraint.cpp
new file mode 100644
index 0000000..7cfccc3
--- /dev/null
+++ b/build/boost/doc/example/quick_constraint.cpp
@@ -0,0 +1,46 @@
+//[ quick_constraint_problem
+#define BOOST_AUTO_TEST_MAIN
+#include <boost/test/auto_unit_test.hpp>
+#include <turtle/mock.hpp>
+#include <iostream>
+
+namespace
+{
+    class my_class
+    {
+    public:
+        explicit my_class( int data )
+	    : data_( data )
+        {}
+        int data_;
+    };
+    std::ostream& operator<<( std::ostream& os, const my_class& c ) // my_class is serializable to an std::ostream
+    {
+        return os << "my_class( " << c.data_ << " )";
+    }
+
+    MOCK_CLASS( my_mock )
+    {
+        MOCK_METHOD( method, 1, void( const my_class& ) ) // how to simply write a custom constraint ?
+    };
+}
+//]
+
+//[ quick_constraint_solution
+#include <boost/lexical_cast.hpp>
+
+namespace mock // it could also be in the namespace of 'my_class'
+{
+    bool operator==( const my_class& actual, const std::string& expected ) // the trick is to compare to a string
+    {
+        return boost::lexical_cast< std::string >( actual ) == expected;
+    }
+}
+
+BOOST_AUTO_TEST_CASE( method_is_called )
+{
+    my_mock mock;
+    MOCK_EXPECT( mock.method ).once().with( "my_class( 42 )" ); // the constraint is given as a string
+    mock.method( my_class( 42 ) );
+}
+//]
diff --git a/build/boost/doc/patterns.qbk b/build/boost/doc/patterns.qbk
index c95bbfd..e87a27b 100644
--- a/build/boost/doc/patterns.qbk
+++ b/build/boost/doc/patterns.qbk
@@ -2,6 +2,7 @@
 [import example/async_call.cpp]
 [import example/retrieve_cref.cpp]
 [import example/invoke_functor.cpp]
+[import example/quick_constraint.cpp]
 
 This section highlights not-so-obvious features of the library gathered from real use cases.
 
@@ -41,4 +42,16 @@ Solution :
 
 [endsect]
 
+[section Quickly writing a custom constraint for a serializable type]
+
+Problem :
+
+[quick_constraint_problem]
+
+Solution :
+
+[quick_constraint_solution]
+
+[endsect]
+
 [endsect]