.. _program_listing_file_dx2_beam_ops.cxx:

Program Listing for File beam_ops.cxx
=====================================

|exhale_lsh| :ref:`Return to documentation for file <file_dx2_beam_ops.cxx>` (``dx2/beam_ops.cxx``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   
   #include <dx2/beam.hpp>
   #include <dx2/beam_ops.hpp>
   #include <stdexcept>
   #include <variant>
   
   namespace beam_ops {
   
   MonochromaticBeam &require_monochromatic(Beam &beam) {
     if (auto *b = std::get_if<MonochromaticBeam>(&beam)) {
       return *b;
     }
     throw std::invalid_argument("Beam must be monochromatic");
   }
   
   const MonochromaticBeam &require_monochromatic(const Beam &beam) {
     if (auto *b = std::get_if<MonochromaticBeam>(&beam)) {
       return *b;
     }
     throw std::invalid_argument("Beam must be monochromatic");
   }
   
   PolychromaticBeam &require_polychromatic(Beam &beam) {
     if (auto *b = std::get_if<PolychromaticBeam>(&beam)) {
       return *b;
     }
     throw std::invalid_argument("Beam must be polychromatic");
   }
   
   const PolychromaticBeam &require_polychromatic(const Beam &beam) {
     if (auto *b = std::get_if<PolychromaticBeam>(&beam)) {
       return *b;
     }
     throw std::invalid_argument("Beam must be polychromatic");
   }
   
   } // namespace beam_ops