Make Pose3<T>::error() static instead of a friend.

The ADL-based friend lookup is helpful for operators but confusing and unnecessary for regular functions.
farm-ng · Dec 17, 2024 · 25fffee · 25fffee
1 parent ef19cee
commit 25fffee
Show file tree

Hide file tree

Showing 2 changed files with 2 additions and 5 deletions.
diff --git a/cpp/sophus/lie/pose3.h b/cpp/sophus/lie/pose3.h
@@ -102,7 +102,7 @@ class Pose3 {
         tangent_in_b_);
   }
 
-  friend Expected<Tangent> error(
+  static Expected<Tangent> error(
       Pose3 const& lhs_a_from_b, Pose3 const& rhs_a_from_b) {
     return (lhs_a_from_b.inverse() * rhs_a_from_b)
         .and_then([](Expected<Pose3> const& pose) -> Expected<Tangent> {

diff --git a/py/pybind/lie_pybind.cpp b/py/pybind/lie_pybind.cpp
@@ -332,11 +332,8 @@ void bind_lie(py::module_& m) {
       .def_static(
           "error",
           [](sophus::Pose3F64 const& lhs_a_from_b, sophus::Pose3F64 const& rhs_a_from_b) {
-            // Note: error is a friend function defined inline in Pose3<T>, so it can only
-            // be found via ADL. That requires unqualified name lookup; sophus::error
-            // would not be found.
             farm_ng::Expected<sophus::Pose3F64::Tangent> err =
-                error(lhs_a_from_b, rhs_a_from_b);
+                sophus::Pose3F64::error(lhs_a_from_b, rhs_a_from_b);
             if (err) {
               return err->array();
             }