Make left() and right() of components accessible from Python

doc/news/leftright.rst

@@ -0,0 +1,3 @@
+**Fixed:**
+
+* Fixed access to `left()` and `right()` of a component from Python.

libintervalxt/intervalxt/forward.hpp

@@ -2,7 +2,7 @@
  *  This file is part of intervalxt.
  *
  *        Copyright (C) 2019 Vincent Delecroix
- *        Copyright (C) 2019-2021 Julian Rüth
+ *        Copyright (C) 2019-2024 Julian Rüth
  *
  *  intervalxt is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -59,19 +59,7 @@ class Serializable;
 template <typename T>
 struct Serialization;
 
-// Cling cannot handle the variant used in recent C++ standard library
-// implementations yet, see https://sft.its.cern.ch/jira/browse/ROOT-10220.
-// Since we heavily rely on cling through cppyy, we should probably use a
-// non-standard variant implementation that does not have these issues, see
-// https://github.com/flatsurf/intervalxt/issues/144. Here we just provide a
-// dirty workaround: this makes Side not usable in cppyy but at least you can
-// `import pyintervalxt` and use functionality that does not use the exposed
-// Side interface.
-#ifndef __CLING__
 using Side = std::variant<Connection, HalfEdge>;
-#else
-using Side = std::array<char, 32>;
-#endif
 
 }  // namespace intervalxt
 

pyintervalxt/src/pyintervalxt/cppyy_intervalxt.py

@@ -2,7 +2,7 @@
 #  This file is part of intervalxt.
 #
 #        Copyright (C) 2019-2020 Vincent Delecroix
-#        Copyright (C) 2019-2022 Julian Rüth
+#        Copyright (C) 2019-2024 Julian Rüth
 #
 #  intervalxt is free software: you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -131,6 +131,16 @@ def from_vector_vector_mpq(v):
 cppyy.py.add_pythonization(filtered("IntervalExchangeTransformation")(wrap_method("boshernitzanEquations")(lambda self, equations: from_vector_vector_mpq(equations()))), "intervalxt")
 cppyy.py.add_pythonization(filtered("IntervalExchangeTransformation")(wrap_method("boshernitzanSaddleConnectionValues")(lambda self, values, top, bottom: from_vector_mpq(values(top, bottom)))), "intervalxt")
 
+# Make left & right of components functional.
+def connections(variants):
+    connections = [cppyy.gbl.std.get[0](c) for c in variants]
+    for variant, c in zip(variants, connections):
+        c._variant = variant
+    return connections
+
+cppyy.py.add_pythonization(filtered("Component")(wrap_method("left")(lambda self, left: connections(left()))), "intervalxt")
+cppyy.py.add_pythonization(filtered("Component")(wrap_method("right")(lambda self, right: connections(right()))), "intervalxt")
+
 # Expose methods on type-erased intervalxt::Lengths.
 cppyy.py.add_pythonization(filtered("any<intervalxt::LengthsInterface,boost::type_erasure::_self>")(expose("push")), "boost::type_erasure")
 cppyy.py.add_pythonization(filtered("any<intervalxt::LengthsInterface,boost::type_erasure::_self>")(expose("pop")), "boost::type_erasure")

pyintervalxt/test/interval_exchange_transformation.py

@@ -165,6 +165,14 @@ def test_decompose(iet):
 
     assert cyls + mins == decomposition.components().size()
 
+    # Test that all sides of cylinders are glued somewhere
+    connections = []
+    for component in decomposition.components():
+        connections.extend(component.left())
+        connections.extend(component.right())
+
+    assert all(-connection in connections for connection in connections)
+
 
 def test_lengths(iet, lengths):
     r"""