core: fix StdVectorPythonVisitor::expose API

include/eigenpy/registration_class.hpp

@@ -30,6 +30,12 @@ class registration_class {
     return *this;
   }
 
+  template <class DerivedVisitor>
+  self& def(bp::def_visitor<DerivedVisitor> const& visitor) {
+    static_cast<DerivedVisitor const&>(visitor).visit(*this);
+    return *this;
+  }
+
   /// \see boost::python::class_::def(char const* name, F f)
   template <class F>
   self& def(char const* name, F f) {

include/eigenpy/std-vector.hpp

@@ -67,7 +67,7 @@ struct build_list<vector_type, true> {
   }
 };
 
-/// \brief Change the behaviour of indexing (method __getitem__ in Python).
+/// \brief Change the behavior of indexing (method __getitem__ in Python).
 /// This is suitable for container of Eigen matrix objects if you want to mutate
 /// them.
 template <typename Container>
@@ -418,14 +418,17 @@ struct StdVectorPythonVisitor {
     expose(class_name, doc_string, EmptyPythonVisitor());
   }
 
-  template <typename Visitor>
-  static void expose(const std::string &class_name, const Visitor &visitor) {
+  template <typename DerivedVisitor>
+  static void expose(
+      const std::string &class_name,
+      const boost::python::def_visitor<DerivedVisitor> &visitor) {
     expose(class_name, "", visitor);
   }
 
-  template <typename Visitor>
-  static void expose(const std::string &class_name,
-                     const std::string &doc_string, const Visitor &visitor) {
+  template <typename DerivedVisitor>
+  static void expose(
+      const std::string &class_name, const std::string &doc_string,
+      const boost::python::def_visitor<DerivedVisitor> &visitor) {
     // Apply visitor on already registered type or if type is not already
     // registered, we define and apply the visitor on it
     auto add_std_visitor =