Changes to MCParticle pointer handling and new Charge() method

Event/EventBase/include/Event/FunctorDefaults.h

@@ -274,6 +274,16 @@ namespace LHCb::Event {
     return pid( *item );
   }
 
+  template <typename T>
+  auto charge( T const& item ) -> decltype( item.charge() ) {
+    return item.charge();
+  }
+  template <typename T>
+  auto charge( T const& item ) -> details::require_pointer_t<T, decltype( charge( *item ) )> {
+    details::check_null_pointer( item, __PRETTY_FUNCTION__ );
+    return charge( *item );
+  }
+
   template <typename T>
   auto decayProducts( T const& item ) -> decltype( item.decayProducts() ) {
     // return a 'range' of decay products, i.e. something

Event/MCEvent/include/Event/MCParticle.h

@@ -269,6 +269,8 @@ namespace LHCb {
 
     friend auto pid( const MCParticle& p ) { return p.particleID().pid(); }
 
+    friend auto charge( const MCParticle& p ) { return p.particleID().threeCharge() / 3; };
+
   private:
     Gaudi::LorentzVector           m_momentum{0.0, 0.0, 0.0, -1 * Gaudi::Units::GeV}; ///< 4-momentum-vector
     LHCb::ParticleID               m_particleID{0};                                   ///< Particle ID