Merge branch 'issue/result-of-t' into 'master'

Replaced result of t by invoke result t

See merge request !33

dune/curvedgrid/gridfunctions/analyticdiscretefunction.hh

@@ -48,7 +48,7 @@ public:
   using ctype = typename Geometry::ctype;
 
   using Domain = typename Geometry::GlobalCoordinate;
-  using RangeType = std::result_of_t<Functor(Domain)>;
+  using RangeType = std::invoke_result_t<Functor,Domain>;
 
   template <int degree>
   using DerivativeRange = typename Impl::DerivativeRangeType<RangeType(Domain), degree, Functions::DefaultDerivativeTraits>::type;
@@ -228,7 +228,7 @@ public:
   using EntitySet = GridEntitySet<Grid,0>;
 
   using Domain = typename EntitySet::GlobalCoordinate;
-  using Range = std::result_of_t<Functor(Domain)>;
+  using Range = std::invoke_result_t<Functor,Domain>;
   using Signature = Range(Domain);
 
 public:

src/example4.cc

@@ -58,7 +58,7 @@ int main(int argc, char** argv)
   GridFactory<GridType> factory;
   GridCreator creator(factory);
 
-  VtkReader reader(creator);
+  Vtk::VtkReader reader(creator);
   reader.read("sphere_order3.vtu");
   std::unique_ptr grid = reader.createGrid();