text: // The MIT License (MIT)
  //
  // Copyright (c) 2018 Mateusz Pusz
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in all
  // copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  // SOFTWARE.
  
  #pragma once
  
  // IWYU pragma: begin_exports
  #include <units/symbol_text.h>
  // IWYU pragma: end_exports
  
  #include <units/quantity_cast.h>
  
  namespace units {
  
  struct one : named_unit<one, "", no_prefix> {};
  struct percent : named_scaled_unit<percent, "%", no_prefix, ratio(1, 100), one> {};
  
  /**
   * @brief Dimension one
   *
   * Dimension for which all the exponents of the factors corresponding to the base
   * dimensions are zero. Also commonly named as "dimensionless".
   */
  struct dim_one : derived_dimension<dim_one, one> {};
  
  template<typename T>
  concept Dimensionless = QuantityOf<T, dim_one>;
  
  template<UnitOf<dim_one> U, Representation Rep = double>
  using dimensionless = quantity<dim_one, U, Rep>;
  
  }  // namespace units
  