FIND_DECAY and FIND_MCDECAY functor

Create two functor named FIND_DECAY and FIND_MC_DECAY that implements respectively the algorithms DecayFinder (new, see !3091 (merged)) and MCDecayFinder.

To be used in composition with other functors to get information about particles belonging to the decay chain.

FIND_DECAY (FIND_MC_DECAY) is MAP of _FIND_DECAY (_FIND_MC_DECAY), functor accepting const LHCb::Particle* (const LHCb::MCParticle*) or const LHCb::Particle& (const LHCb::MCParticle&) and returning a const LHCb::Particle* (const LHCb::MCParticle*).

TODO:

• Fix test;
• Adapt the functor to support MCParticles.

Perhaps related to issue: #356

Example in the DV MR DaVinci!781 (merged)

cc: @amathad

Phys/FunctorCore/tests/src/InstantiateFunctors.cpp

@@ -335,8 +335,9 @@ using npvs_func_type = decltype( npvs_func.prepare( EventContext{}, Functors::To
 using npvs_func_res_type = std::invoke_result_t<npvs_func_type, bool, LHCb::RecSummary const&>;
 using inmuon_1           = std::invoke_result_t<FT::InAcceptance, LHCb::Particle const&>;
 
+
 // Create an instance for FIND_DECAY functor
-using find_decay_func = Functors::chain(
+auto find_decay_func = Functors::chain(
     ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ), ::FC::Rho_Coordinate{},
     ::FT::ThreeMomentum{}, ::FF::Front{},
     ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{"[B0->K+ pi-]CC"} ),
@@ -347,8 +348,8 @@ using find_decay_func_type = decltype( find_decay_func.prepare( EventContext{},
 // The bool needs to be there since it is a mask to be passed to prepared functor
 // Then the actual input is passed forwarding the arguments (LHCb::Particle const ref).
 using find_decay_func_result_type = std::invoke_result_t<find_decay_func_type, bool, LHCb::Particle const&>;
-// Check no.2: instead of using a dummy tes location, trying passing directly a std::vector<LHCb::Particle const&>
-using find_decay_func2 = Functors::chain( ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ),
+// Test no.2: instead of using a dummy tes location, trying passing directly a std::vector<LHCb::Particle const&>
+auto find_decay_func2 = Functors::chain( ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ),
                                           ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FF::Front{},
                                           ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{
                                               "[B0->K+ pi-]CC"} ) );