Extract

Template metafunction for extracting types from tuple structures.

template <
  class ... _1>
struct Extract;

template <
  class T,
  class ... Ts>
struct Extract<
  Tuple< T, Ts... >>;

The Extract template provides a mechanism to apply a type transformation (Extractor) to each element type in a tuple, producing a new tuple with the transformed types.

This is useful for type-level transformations such as adding const qualifiers, extracting nested types, or applying other template metafunctions to tuple elements.