Typelist - GerdHirsch/Cpp-VisitorFrameworkCyclicAcyclic GitHub Wiki

Typelist is a non defined template, just to specialize another templates:

template<class ...Types>
struct Typelist;

For example, MyVisitor : visits<typelist> can be used with a typelist, because of specialization:

template<class ...ToVisit>
struct visits : VisitorBase{};

template<class ...ToVisit>
struct visits<VisitorFramework::Typelist<ToVisit...>>
// delegates to primary DRY Principle
: visits<ToVisit...>{};

Both implementations of visits delegates their implementations to their base class. The specialization to the primary and the primary template to VisitorBase thereby discarding the list in case of the cyclic Repository.

Typelist is very useful and often used i.e. by Repository of the framework.