Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of Boost. Click here to view this page for the latest version.

Struct template if_else_

boost::proto::if_else_ — A metafunction for generating ternary conditional expression types, a grammar element for matching ternary conditional expressions, and a PrimitiveTransform that dispatches to the proto::pass_through<> transform.


// In header: <boost/proto/traits.hpp>

template<typename T, typename U, typename V> 
struct if_else_ :  proto::transform< if_else_<T, U, V> > {
  // types
  typedef proto::expr< proto::tag::if_else_, proto::list3< T, U, V > >       type;         
  typedef proto::basic_expr< proto::tag::if_else_, proto::list3< T, U, V > > proto_grammar;

  // member classes/structs/unions
  template<typename Expr, typename State, typename Data> 
  struct impl :
     proto::pass_through<if_else_>::template impl<Expr, State, Data>