SV
class classA ;
// class_items
endclass // : classA とラベルも書ける
class classA parameter_port_list ;
class classA extends class_type ;
class classA extends class_type ( arglist );
class classA implements interface_class_type ;
virtual class classA;
class lifetime classA;
[ virtual ] class [ lifetime ] class_id [ parameter_port_list ]
[ extends class_type [ ( list_of_args ) ]
[ implements interface_class_type { , interface_class_type } ] ;
{ class_item }
endclass [ : class_id ]