introduced field_attributes shortcuts and added method on_base() to all processor classes

include/matador/utils/primary_key_accessor.hpp

@@ -21,6 +21,8 @@ public:
     access::process(*this, obj);
   }
 
+  template<typename BaseType>
+  static void on_base(const BaseType&) {}
   template<typename PrimaryKeyType>
   void on_primary_key(const char * /*id*/, PrimaryKeyType &pk, const primary_key_attribute & = DefaultPkAttributes) {
     const auto value = pk_.as<PrimaryKeyType>();
@@ -51,6 +53,8 @@ private:
 struct pk_unset_checker {
   bool unset{true};
 
+  template<typename BaseType>
+  static void on_base(const BaseType&) {}
   template<class PrimaryKeyType>
   void on_primary_key(const char * /*id*/, PrimaryKeyType &pk, const primary_key_attribute & = DefaultPkAttributes) {
     unset = !identifier_type_traits<PrimaryKeyType>::is_valid(pk);
@@ -73,6 +77,8 @@ struct pk_unset_checker {
 struct primary_key_getter {
   std::uint64_t value{0};
 
+  template<typename BaseType>
+  static void on_base(const BaseType&) {}
   template<class PrimaryKeyType>
   void on_primary_key(const char * /*id*/, PrimaryKeyType &pk, const primary_key_attribute & = DefaultPkAttributes) {
     pk_ = pk;