More repr, fix infinite loop when calling repr on a lanele->regelem->lanelet cycle (#383)

Author: poggenhans

lanelet2_python/include/lanelet2_python/internal/repr.h

@@ -0,0 +1,51 @@
+#pragma once
+#include <boost/python.hpp>
+#include <sstream>
+#include <string>
+
+namespace lanelet {
+namespace python {
+inline void formatHelper(std::ostream& os) {}
+
+template <typename... Args>
+// NOLINTNEXTLINE(readability-identifier-naming)
+void formatHelper(std::ostream& os, const std::string& s, const Args&... Args_) {
+  if (!s.empty()) {
+    os << ", ";
+  }
+  os << s;
+  formatHelper(os, Args_...);
+}
+
+template <typename T, typename... Args>
+// NOLINTNEXTLINE(readability-identifier-naming)
+void formatHelper(std::ostream& os, const T& next, const Args&... Args_) {
+  os << ", ";
+  os << next;
+  formatHelper(os, Args_...);
+}
+
+template <typename T, typename... Args>
+// NOLINTNEXTLINE(readability-identifier-naming)
+void format(std::ostream& os, const T& first, const Args&... Args_) {
+  os << first;
+  formatHelper(os, Args_...);
+}
+
+template <typename... Args>
+// NOLINTNEXTLINE(readability-identifier-naming)
+std::string makeRepr(const char* name, const Args&... Args_) {
+  std::ostringstream os;
+  os << name << '(';
+  format(os, Args_...);
+  os << ')';
+  return os.str();
+}
+
+inline std::string repr(const boost::python::object& o) {
+  using namespace boost::python;
+  object repr = import("builtins").attr("repr");
+  return call<std::string>(repr.ptr(), o);
+}
+}  // namespace python
+}  // namespace lanelet