Make it compile

Author: Joseph-Edwards

src/present.cpp

@@ -456,7 +456,8 @@ alphabet of *p*, and where :math:`e` is the second parameter.
           },
           py::arg("p"),
           py::arg("vals"),
-          py::arg("e") = static_cast<Presentation_::letter_type>(UNDEFINED),
+          py::arg("e")
+          = static_cast<typename Presentation_::letter_type>(UNDEFINED),
           R"pbdoc(
 :sig=(p: Presentation, vals: Word, e: Letter = UNDEFINED) -> None:
 :only-document-once:
@@ -1383,7 +1384,7 @@ defined in the alphabet, and that the inverses act as semigroup inverses.
       * :any:`presentation.throw_if_bad_inverses`
 )pbdoc");
     }  // bind_inverse_present
-  }  // namespace
+  }    // namespace
 
   void init_present(py::module& m) {
     bind_present<word_type>(m, "PresentationWords");

src/word-graph.cpp

@@ -307,14 +307,13 @@ had just been newly constructed with the same parameters *m* and *n*.
         [](WordGraph_ const& self, node_type source) {
           auto r = (self.labels_and_targets(source)
                     | rx::transform(
-                        [](std::pair<label_type, node_type> const& label_target)
+                        [](auto const& label_target)
                             -> std::pair<label_type, int_or_undefined> {
-                          std::pair<label_type, int_or_undefined> result(
-                              label_target.first, {UNDEFINED});
-                          if (label_target.second != UNDEFINED) {
-                            result.second = label_target.second;
+                          if (std::get<1>(label_target) != UNDEFINED) {
+                            return {std::get<0>(label_target),
+                                    {std::get<1>(label_target)}};
                           }
-                          return result;
+                          return {std::get<0>(label_target), {UNDEFINED}};
                         }));
           return py::make_iterator(rx::begin(r), rx::end(r));
         },