Merge pull request #10018 from bangerth/iota-range

Introduce std_cxx20::ranges::iota_view

diff --cc include/deal.II/base/geometry_info.h
index 60772c85af87ca1b7fc0ab09df98235eed971392,04f6646c5e3ef9585249d0f492d34b23ad5b5e57..5fab2b0419f8a672cfa7e380e65cc66b21ac658b
--- 1/include/deal.II/base/geometry_info.h
--- 2/include/deal.II/base/geometry_info.h
+++ b/include/deal.II/base/geometry_info.h
@@@ -1946,10 -1945,8 +1945,10 @@@ struct GeometryInf
     * Here, we are looping over all faces of all cells, with `face_index`
     * taking on all valid indices for faces (zero and one in 1d, zero
     * through three in 2d, and zero through 5 in 3d).
 +   *
 +   * @see CPP11
     */
-   static boost::integer_range<unsigned int>
+   static std_cxx20::ranges::iota_view<unsigned int, unsigned int>
    face_indices();
  
    /**
@@@ -1979,10 -1976,8 +1978,10 @@@
     * @endcode
     * Here, we are looping over all vertices of all cells, with `vertex_index`
     * taking on all valid indices.
 +   *
 +   * @see CPP11
     */
-   static boost::integer_range<unsigned int>
+   static std_cxx20::ranges::iota_view<unsigned int, unsigned int>
    vertex_indices();
  
    /**

diff --cc include/deal.II/fe/fe_values.h
index cb2ac3b01723cbd03a9103be445cea098aeaad42,33bd3f127624cea82144eeee5a34e4bb5675f9ee..343f19d211a5e9dfbfd42214abf889b369ef68ea
--- 1/include/deal.II/fe/fe_values.h
--- 2/include/deal.II/fe/fe_values.h
+++ b/include/deal.II/fe/fe_values.h
@@@ -3030,10 -3029,8 +3029,10 @@@ public
     * Here, we are looping over all quadrature points on all cells, with
     * `q_point` taking on all valid indices for quadrature points, as defined
     * by the quadrature rule passed to `fe_values`.
 +   *
 +   * @see CPP11
     */
-   boost::integer_range<unsigned int>
+   std_cxx20::ranges::iota_view<unsigned int, unsigned int>
    quadrature_point_indices() const;
  
    /**