python: support iteration over vectors.

src/python/magnum/math.cpp

@@ -125,9 +125,16 @@ template<class T> void boolVector(py::class_<T>& c) {
         .def("none", &T::none, "Whether no bits are set")
         .def("any", &T::any, "Whether any bit is set")
 
-        /* Set / get */
-        .def("__setitem__", &T::set, "Set a bit at given position", py::arg("i"), py::arg("value"))
-        .def("__getitem__", &T::operator[], "Bit at given position")
+        /* Set / get. Need to throw IndexError in order to allow iteration:
+           https://docs.python.org/3/reference/datamodel.html#object.__getitem__ */
+        .def("__setitem__",[](T& self, std::size_t i, bool value) {
+            if(i >= T::Size) throw pybind11::index_error{};
+            self.set(i, value);
+        }, "Set a bit at given position")
+        .def("__getitem__", [](const T& self, std::size_t i) {
+            if(i >= T::Size) throw pybind11::index_error{};
+            return self[i];
+        }, "Bit at given position")
 
         /* Operators */
         .def(~py::self, "Bitwise inversion")

src/python/magnum/math.vector.h

@@ -63,11 +63,14 @@ template<class T> void vector(py::module& m, py::class_<T>& c) {
         .def(py::self <= py::self, "Component-wise less than or equal comparison")
         .def(py::self >= py::self, "Component-wise greater than or equal comparison")
 
-        /* Set / get */
+        /* Set / get. Need to throw IndexError in order to allow iteration:
+           https://docs.python.org/3/reference/datamodel.html#object.__getitem__ */
         .def("__setitem__", [](T& self, std::size_t i, typename T::Type value) {
+            if(i >= T::Size) throw pybind11::index_error{};
             self[i] = value;
         }, "Set a value at given position")
         .def("__getitem__", [](const T& self, std::size_t i) {
+            if(i >= T::Size) throw pybind11::index_error{};
             return self[i];
         }, "Value at given position")
 

src/python/magnum/test/test_math.py

@@ -91,6 +91,10 @@ class BoolVector(unittest.TestCase):
         a[2] = True
         self.assertEqual(a, BoolVector4(0b1110))
 
+    def test_iterate(self):
+        a = [i for i in BoolVector4(0b1010)]
+        self.assertEqual(a, [False, True, False, True])
+
     def test_ops(self):
         a = BoolVector3(0b101) | BoolVector3(0b010)
         self.assertEqual(a, BoolVector3(0b111))
@@ -219,6 +223,12 @@ class Vector(unittest.TestCase):
         b.xy += Vector2i(1, -1)
         self.assertEqual(b, Vector4i(4, 3, 15, 6))
 
+    def test_iterate(self):
+        a = [i for i in Vector4(1.0, 3.25, 3.5, -1.125)]
+        # assertAlmostEqual doesn't work on lists so i'm using values directly
+        # representable as floats to avoid the need for delta comparison
+        self.assertEqual(a, [1.0, 3.25, 3.5, -1.125])
+
     def test_ops(self):
         self.assertEqual(math.dot(Vector2(0.5, 3.0), Vector2(2.0, 0.5)), 2.5)
         self.assertEqual(Deg(math.angle(