Add treepath literal _tp and a test

amdis/typetree/TreePath.hpp

 #pragma once
 
+#include <cassert>
 #include <sstream>
 #include <string>
 #include <type_traits>
@@ -10,6 +11,7 @@
 #include <dune/typetree/typetraits.hh>
 
 #include <amdis/common/Apply.hpp>
+#include <amdis/common/Literals.hpp>
 #include <amdis/common/Logical.hpp>
 
 namespace AMDiS {
@@ -150,6 +152,14 @@ auto makeTreePath(Dune::TypeTree::StaticTreePath<I...>)
 #endif // DOXYGEN
 
 
+/// Literal to create treepath, e.g. 021_tp -> HybridTreePath<index_t<0>,index_t<2>,index_t<1>>
+template <char... digits>
+constexpr auto operator"" _tp()
+{
+  return Dune::TypeTree::hybridTreePath(std::integral_constant<std::size_t,Impl::char2digit(digits)>{}...);
+}
+
+
 // convert a treepath into a string, comma-separated
 template <class... T>
 std::string to_string(Dune::TypeTree::HybridTreePath<T...> const& tp)

test/TreePathTest.cpp

@@ -10,6 +10,16 @@
 using namespace AMDiS;
 using namespace Dune::Indices;
 
+template <class... I, class... J,
+  std::enable_if_t<(sizeof...(I) == sizeof...(J)), int> =0>
+bool compare(Dune::TypeTree::HybridTreePath<I...> const& tp1, Dune::TypeTree::HybridTreePath<J...> const& tp2)
+{
+  return Ranges::applyIndices<sizeof...(I)>([&](auto... i) {
+    return ((tp1[i] == tp2[i]) &&...);
+  });
+}
+
+
 int main (int argc, char** argv)
 {
   Environment env(argc, argv);
@@ -36,4 +46,11 @@ int main (int argc, char** argv)
 
   auto tp = Dune::TypeTree::hybridTreePath(1u, _2);
   static_assert( std::is_same_v<TYPEOF(tp), TYPEOF(makeTreePath(tp))> );
+
+  AMDIS_TEST(compare(tp, 12_tp));
+  AMDIS_TEST(compare(makeTreePath(1,2), 12_tp));
+  AMDIS_TEST(compare(makeTreePath(0,1,2), 012_tp));
+  AMDIS_TEST(compare(makeTreePath(0,0,1,2), 0012_tp));
+
+  return report_errors();
 }