reduce.hpp

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#pragma once

#include <atria/xform/detail/reduce_nested_non_empty.hpp>
#include <atria/xform/detail/is_non_empty.hpp>
#include <atria/xform/state_traits.hpp>

namespace atria {
namespace xform {

template <typename ReducingFnT,
          typename StateT,
          typename ...InputRangeTs>
auto reduce(ReducingFnT&& step, StateT&& state, InputRangeTs&& ...ranges)
  -> estd::decay_t<StateT>
{
  return detail::is_non_empty(ranges...)
    ? state_complete(
      detail::reduce_nested_non_empty(
        std::forward<ReducingFnT>(step),
        std::forward<StateT>(state),
        std::forward<InputRangeTs>(ranges)...))
    : std::forward<StateT>(state);
}

} // namespace xform
} // namespace atria