draconisplusplus/include/rfl/AllOf.hpp

#ifndef RFL_ALLOF_HPP_
#define RFL_ALLOF_HPP_

#include <vector>

#include "Result.hpp"
#include "parsing/schema/ValidationType.hpp"

namespace rfl {

  /// Requires that all of the contraints C and Cs be true.
  template <class C, class... Cs>
  struct AllOf {
    template <class T>
    static rfl::Result<T> validate(T _value) noexcept {
      return validate_impl<T, C, Cs...>(_value);
    }

    template <class T>
    static parsing::schema::ValidationType to_schema() {
      using ValidationType = parsing::schema::ValidationType;
      const auto types =
        std::vector<ValidationType>({ C::template to_schema<T>(), Cs::template to_schema<T>()... });
      return ValidationType { ValidationType::AllOf { .types_ = types } };
    }

   private:
    template <class T, class Head, class... Tail>
    static rfl::Result<T> validate_impl(T _value) noexcept {
      if constexpr (sizeof...(Tail) == 0) {
        return Head::validate(_value);
      } else {
        return Head::validate(_value).and_then(validate_impl<T, Tail...>);
      }
    }
  };

} // namespace rfl

#endif