serif::dimensions::Velocity serif::dimensions::PhysicalQuantity dimensions.hpp std::string_view std::string_view serif::dimensions::Velocity::identifier identifier serif::dimensions::Velocity::identifier = "velocity" Dimension of Velocity. serif::dimensions::PhysicalQuantity serif::dimensions::Velocity serif::dimensions::PhysicalQuantity serif::dimensions::Velocity identifier std::basic_string_view< Char > std::string_view serif::dimensions::Velocityidentifier