Hello, The documentation of BOOST_FUSION_DEFINE_STRUCT says it should be used at global scope. Why can't this function be used at namespace scope, and, especially, at class scope? Not being able to use it at namespace scope is just as annoyance because it means the current namespace(s) have to be closed before the macro and re-opened after it; but not being able to use it at class scope means that it cannot be used to declare nested structures which are fusion sequences at all. Is there another device that allows us to declare nested structure that are fusion sequences? Thanks, Nate.