backmp11: Improve serializer interface #197
Description
The serializer interface in backmp11 is defined as a generic friend declaration without providing an implementation.
While this allows different user-provided serializer implementations, it requires users to understand implementation details of the back-end and potentially breaks when the implementation details change.
Consider potential improvements to decouple the user-provided serializer implementation from backmp11 implementation details.
Idea collection:
Idea 1: Adapt the interface to require generic operators on the serializer that only gets builtins as input
In place of a friend declaration we define a function that forwards its members on the archive argument. Example:
template<typename T, typename A0, typename A1, typename A2>
void serialize(T& archive, state_machine_base<A0, A1, A2>& sm)
{
archive & sm.member_1;
archive & sm.member_2;
...
}The serialization methods should be chosen in a way to support a generic way of integrating different serialization frameworks.
The more frameworks are supported out-of-the-box the better. In case the methods don't match, an adapter pattern shall be possible to implement the needed syntax for the framework.
Existing serialization frameworks
Boost.Serialization:
132 stars on GitHub but probably a widely used library. Stars for Boost libraries have limited significance.
- bidirectional syntax:
operator&on the archive - Input/output syntax:
operator>>,operator<<on the archive
cereal:
4.6k stars on GitHub, seems widespread. Inspired by Boost.Serialization, said to be a moremodern alternative.
- bidirectional syntax:
operator()on the archive with support for variadic arguments - Alternatively supports the Boost.Serlization operators for compatibility reasons
zpp_bits:
1k stars on GitHub.
- bidirectional syntax:
operator()on the archive with support for variadic arguments
bitsery:
1.2k stars on GitHub. Claims to be very efficient.
- bidirectional syntax: Custom methods of the archive depending on the phyiscal layout
- examples:
archive.value1b(sm.m_event_processing);
- examples:
Requires library-specific adapter code due to the custom methods.
nlohman/json:
49.3k stars on GitHub.
Does not work with binary streams, all state machine members must be passed with keys for identification.
Possiblity for support needs to be investigated. It would be a nice feature for easy introspection into a state machine.