Method operator|

extlibs/catch/include/catch/catch.hpp:9330–9332

    template<typename DerivedT>
    template<typename T>
    auto ComposableParserImpl<DerivedT>::operator|( T const &other ) const -> Parser {
        return Parser() | static_cast<DerivedT const &>( *this ) | other;
    }
} // namespace detail

// A Combined parser