Ifpack2_Details_getParamTryingTypes.hpp

// @HEADER
// *****************************************************************************
//       Ifpack2: Templated Object-Oriented Algebraic Preconditioner Package
//
// Copyright 2009 NTESS and the Ifpack2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER
 
#ifndef IFPACK2_DETAILS_GETPARAMTRYINGTYPES_HPP
#define IFPACK2_DETAILS_GETPARAMTRYINGTYPES_HPP
 
#include "Ifpack2_config.h"
#include "Teuchos_TypeNameTraits.hpp"
#include "Teuchos_ParameterList.hpp"
 
namespace Ifpack2 {
namespace Details {
 
template <class... CandidateTypes>
struct GetParamTryingTypes {
  template <class ResultType>
  static void
  get(ResultType& result,
      const Teuchos::ParameterEntry& ent,
      const std::string& paramName,
      const char prefix[]);
};
 
template <>
struct GetParamTryingTypes<> {
  template <class ResultType>
  static void
  get(ResultType& /* result */,
      const Teuchos::ParameterEntry& /* ent */,
      const std::string& paramName,
      const char prefix[]) {
    using Teuchos::TypeNameTraits;
    TEUCHOS_TEST_FOR_EXCEPTION(true, std::invalid_argument, prefix << "\"" << paramName << "\" parameter exists in input ParameterList, but does not "
                                                                                           "have the right type.  The proper type is "
                                                                   << TypeNameTraits<ResultType>::name() << ".");
  }
};
 
template <class First, class... Rest>
struct GetParamTryingTypes<First, Rest...> {
  template <class ResultType>
  static void
  get(ResultType& result,
      const Teuchos::ParameterEntry& ent,
      const std::string& paramName,
      const char prefix[]) {
    if (ent.template isType<First>()) {
      result = static_cast<ResultType>(Teuchos::getValue<First>(ent));
    } else {
      using rest_type = GetParamTryingTypes<Rest...>;
      rest_type::template get<ResultType>(result, ent, paramName, prefix);
    }
  }
};
 
template <class ResultType, class... CandidateTypes>
void getParamTryingTypes(ResultType& result,
                         const Teuchos::ParameterList& params,
                         const std::string& paramName,
                         const char prefix[]) {
  using Teuchos::ParameterEntry;
  const ParameterEntry* ent = params.getEntryPtr(paramName);
  if (ent != nullptr) {
    using impl_type = GetParamTryingTypes<CandidateTypes...>;
    impl_type::template get<ResultType>(result, *ent, paramName, prefix);
  }
}
 
}  // namespace Details
}  // namespace Ifpack2
 
#endif  // IFPACK2_DETAILS_GETPARAMTRYINGTYPES_HPP