From 053db4e03ef28c933ba29d8373ae1864927fadd8 Mon Sep 17 00:00:00 2001
From: ManifoldFR <wilson.jallet@polytechnique.org>
Date: Fri, 25 Apr 2025 11:45:01 +0200
Subject: [PATCH 1/3] Add user-defined literal _a as a shortcut for

---
 include/eigenpy/fwd.hpp | 10 ++++++++++
 unittest/user_type.cpp  |  5 +++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/include/eigenpy/fwd.hpp b/include/eigenpy/fwd.hpp
index 2b348a70c..c0fe4c75f 100644
--- a/include/eigenpy/fwd.hpp
+++ b/include/eigenpy/fwd.hpp
@@ -196,6 +196,16 @@ struct has_operator_equal_impl {
 template <class T1, class T2 = T1>
 struct has_operator_equal : internal::has_operator_equal_impl<T1, T2>::type {};
 
+namespace literals {
+/// \brief A string literal returning a boost::python::arg.
+///
+/// Using-declare this operator or do `using namespace eigenpy::literals`. Then
+/// `bp::arg("matrix")` can be replaced by the literal `"matrix"_a`.
+inline boost::python::arg operator"" _a(const char *name, std::size_t) {
+  return boost::python::arg(name);
+}
+}  // namespace literals
+
 }  // namespace eigenpy
 
 #include "eigenpy/alignment.hpp"
diff --git a/unittest/user_type.cpp b/unittest/user_type.cpp
index 2adbac43e..dee189001 100644
--- a/unittest/user_type.cpp
+++ b/unittest/user_type.cpp
@@ -150,12 +150,13 @@ Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic> build_matrix(int rows,
 template <typename Scalar>
 void expose_custom_type(const std::string& name) {
   using namespace Eigen;
+  using eigenpy::literals::operator"" _a;
   namespace bp = boost::python;
 
   typedef CustomType<Scalar> Type;
 
-  bp::class_<Type>(name.c_str(), bp::init<Scalar>(bp::arg("value")))
-
+  // use ""_a literal
+  bp::class_<Type>(name.c_str(), bp::init<Scalar>("value"_a))
       .def(bp::self + bp::self)
       .def(bp::self - bp::self)
       .def(bp::self * bp::self)

From d43b83c7864b89cd71b0d1dd776c634f68d80edf Mon Sep 17 00:00:00 2001
From: ManifoldFR <wilson.jallet@polytechnique.org>
Date: Fri, 25 Apr 2025 11:51:28 +0200
Subject: [PATCH 2/3] Update CHANGELOG

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3c7546e64..1ddae3fa8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+### Added
+
+- Add user-defined literal ""_a for bp::arg ([#545)(https://github.com/stack-of-tasks/eigenpy/pull/545))
+
 ### Fixed
 
 - Fix handling of non sorted sparse matrix ([#538](https://github.com/stack-of-tasks/eigenpy/pull/538))

From 2792847d1d5186315f765d9a19743e6ecf1f138c Mon Sep 17 00:00:00 2001
From: ManifoldFR <wilson.jallet@polytechnique.org>
Date: Fri, 25 Apr 2025 14:59:33 +0200
Subject: [PATCH 3/3] remove ubuntu 20.04, add 24.04

---
 .github/workflows/linux.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 572714726..3fbfff38f 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         python: [3]
-        ubuntu: [20, 22]
+        ubuntu: [22, 24]
     steps:
       - uses: actions/checkout@v3
         with: