To disable adressof operator, just disable it in your gramamr using proto::not_

I thought about it, but the problem is that Empty has terminal as base class: struct Empty: public state<>, proto::terminal<state_tag> and thus &Empty will reproduce the problem. Or am I missing something obvious? (answer:probably ;-) ) Christophe _________________________________________________________________ Show them the way! Add maps and directions to your party invites. http://www.microsoft.com/windows/windowslive/products/events.aspx