Boost C++ Libraries

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Struct template unpack_expr<Tag, Domain, Sequence>

boost::proto::result_of::unpack_expr<Tag, Domain, Sequence> — Metafunction that computes the return type of the proto::unpack_expr() function, within the specified domain.

Synopsis

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

template<typename Tag, typename Domain, typename Sequence> 
struct unpack_expr<Tag, Domain, Sequence> {
  // types
  typedef 
    typename proto::result_of::make_expr<
      Tag,
      Domain,
      typename fusion::result_of::value_at_c<S, 0>::type,
      ...
      typename fusion::result_of::value_at_c<S, N-1>::type
    >::type
   type;  // Where S is a RandomAccessSequence equivalent to Sequence, and N is the size of S.
};

Description

Computes the return type of the proto::unpack_expr() function.