Dune::Hybrid::HybridFunctor< Functor > Class Template Reference

Adapter of a hybrid functor that maintains results hybrid. More...

#include <dune/common/hybridutilities.hh>

Public Member Functions
template<class... Args>
constexpr decltype(auto)	operator() (const Args &... args) const
	Adapter of a hybrid functor that keeps results hybrid. More...

Detailed Description

template<class Functor>
class Dune::Hybrid::HybridFunctor< Functor >

Adapter of a hybrid functor that maintains results hybrid.

This adapter will return an integral constant if all of the arguments are integral constants. That's helpful to maintain the hybrid nature of a variable after a transformation. For example, applying an operator + between two integral constants will promote the result to its underlying type (e.g. std::size_t). That's inconventient since the value of the result is not encoded in the type anymore, thus, losing its hybrid attribute (maybe still being constexpr).

using namespace Dune::Indices;
{ // non-hybrid transformation!
  auto i =  1 +  2;      // -> 3
  auto j =  1 + _2;      // -> 3
  auto k = _1 + _2;      // -> 3
  // depending of the context, `k` may or may not be constexpr
}
{ // hybrid transformation!
  auto plus = Hybrid::HybridFunctor<std::plus<>>{};
  auto j = plus( 1,  2); // -> 3
  auto j = plus( 1, _2); // -> 3
  auto k = plus(_1, _2); // -> Dune::Indices::_3
  // independent of the context, `k` encodes its value in the type system
}

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The documentation for this class was generated from the following file:

• dune/common/hybridutilities.hh