std::experimental::optional (#475)
* Add type caster for std::experimental::optional
* Add tests for std::experimental::optional
* Support both <optional> / <experimental/optional>
* Mention std{::experimental,}::optional in the docs
diff --git a/docs/advanced/cast/overview.rst b/docs/advanced/cast/overview.rst
index 4df1bd1..e9f43be 100644
--- a/docs/advanced/cast/overview.rst
+++ b/docs/advanced/cast/overview.rst
@@ -75,66 +75,70 @@
an additional extension header to be included). To pass other data structures
as arguments and return values, refer to the section on binding :ref:`classes`.
-+---------------------------------+--------------------------+-------------------------------+
-| Data type | Description | Header file |
-+=================================+==========================+===============================+
-| ``int8_t``, ``uint8_t`` | 8-bit integers | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``int16_t``, ``uint16_t`` | 16-bit integers | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``int32_t``, ``uint32_t`` | 32-bit integers | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``int64_t``, ``uint64_t`` | 64-bit integers | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``ssize_t``, ``size_t`` | Platform-dependent size | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``float``, ``double`` | Floating point types | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``bool`` | Two-state Boolean type | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``char`` | Character literal | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``wchar_t`` | Wide character literal | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``const char *`` | UTF-8 string literal | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``const wchar_t *`` | Wide string literal | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::string`` | STL dynamic UTF-8 string | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::wstring`` | STL dynamic wide string | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::pair<T1, T2>`` | Pair of two custom types | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::tuple<...>`` | Arbitrary tuple of types | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::reference_wrapper<...>`` | Reference type wrapper | :file:`pybind11/pybind11.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::complex<T>`` | Complex numbers | :file:`pybind11/complex.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::array<T, Size>`` | STL static array | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::vector<T>`` | STL dynamic array | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::list<T>`` | STL linked list | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::map<T1, T2>`` | STL ordered map | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::unordered_map<T1, T2>`` | STL unordered map | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::set<T>`` | STL ordered set | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::unordered_set<T>`` | STL unordered set | :file:`pybind11/stl.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::function<...>`` | STL polymorphic function | :file:`pybind11/functional.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::chrono::duration<...>`` | STL time duration | :file:`pybind11/chrono.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``std::chrono::time_point<...>``| STL date/time | :file:`pybind11/chrono.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``Eigen::Matrix<...>`` | Eigen: dense matrix | :file:`pybind11/eigen.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``Eigen::Map<...>`` | Eigen: mapped memory | :file:`pybind11/eigen.h` |
-+---------------------------------+--------------------------+-------------------------------+
-| ``Eigen::SparseMatrix<...>`` | Eigen: sparse matrix | :file:`pybind11/eigen.h` |
-+---------------------------------+--------------------------+-------------------------------+
++------------------------------------+---------------------------+-------------------------------+
+| Data type | Description | Header file |
++=---================================+===========================+===============================+
+| ``int8_t``, ``uint8_t`` | 8-bit integers | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``int16_t``, ``uint16_t`` | 16-bit integers | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``int32_t``, ``uint32_t`` | 32-bit integers | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``int64_t``, ``uint64_t`` | 64-bit integers | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``ssize_t``, ``size_t`` | Platform-dependent size | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``float``, ``double`` | Floating point types | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``bool`` | Two-state Boolean type | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``char`` | Character literal | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``wchar_t`` | Wide character literal | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``const char *`` | UTF-8 string literal | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``const wchar_t *`` | Wide string literal | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::string`` | STL dynamic UTF-8 string | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::wstring`` | STL dynamic wide string | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::pair<T1, T2>`` | Pair of two custom types | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::tuple<...>`` | Arbitrary tuple of types | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::reference_wrapper<...>`` | Reference type wrapper | :file:`pybind11/pybind11.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::complex<T>`` | Complex numbers | :file:`pybind11/complex.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::array<T, Size>`` | STL static array | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::vector<T>`` | STL dynamic array | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::list<T>`` | STL linked list | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::map<T1, T2>`` | STL ordered map | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::unordered_map<T1, T2>`` | STL unordered map | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::set<T>`` | STL ordered set | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::unordered_set<T>`` | STL unordered set | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::optional<T>`` | STL optional type (C++17) | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::experimental::optional<T>`` | STL optional type (exp.) | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::function<...>`` | STL polymorphic function | :file:`pybind11/functional.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::chrono::duration<...>`` | STL time duration | :file:`pybind11/chrono.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``std::chrono::time_point<...>`` | STL date/time | :file:`pybind11/chrono.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``Eigen::Matrix<...>`` | Eigen: dense matrix | :file:`pybind11/eigen.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``Eigen::Map<...>`` | Eigen: mapped memory | :file:`pybind11/eigen.h` |
++------------------------------------+---------------------------+-------------------------------+
+| ``Eigen::SparseMatrix<...>`` | Eigen: sparse matrix | :file:`pybind11/eigen.h` |
++------------------------------------+---------------------------+-------------------------------+
diff --git a/docs/changelog.rst b/docs/changelog.rst
index e837aa4..87d38d3 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -59,6 +59,7 @@
to do it manually via ``PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>)``.
* Default return values policy changes: non-static properties now use ``reference_internal``
and static properties use ``reference`` (previous default was ``automatic``, i.e. ``copy``).
+* Support for ``std::experimental::optional<T>`` and ``std::optional<T>`` (C++17).
* Various minor improvements of library internals (no user-visible changes)
1.8.1 (July 12, 2016)
diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
index e5c6e3c..b3fe157 100644
--- a/include/pybind11/stl.h
+++ b/include/pybind11/stl.h
@@ -22,6 +22,21 @@
#pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
#endif
+#ifdef __has_include
+// std::optional
+# if __has_include(<optional>)
+# include <optional>
+# define PYBIND11_HAS_OPTIONAL 1
+# endif
+// std::experimental::optional
+# if __has_include(<experimental/optional>)
+# include <experimental/optional>
+# if __cpp_lib_experimental_optional // just in case
+# define PYBIND11_HAS_EXP_OPTIONAL 1
+# endif
+# endif
+#endif
+
NAMESPACE_BEGIN(pybind11)
NAMESPACE_BEGIN(detail)
@@ -183,6 +198,47 @@
template <typename Key, typename Value, typename Hash, typename Equal, typename Alloc> struct type_caster<std::unordered_map<Key, Value, Hash, Equal, Alloc>>
: map_caster<std::unordered_map<Key, Value, Hash, Equal, Alloc>, Key, Value> { };
+// This type caster is intended to be used for std::optional and std::experimental::optional
+template<typename T> struct optional_caster {
+ using value_type = typename intrinsic_type<typename T::value_type>::type;
+ using caster_type = type_caster<value_type>;
+
+ static handle cast(const T& src, return_value_policy policy, handle parent) {
+ if (!src)
+ return none();
+ return caster_type::cast(*src, policy, parent);
+ }
+
+ bool load(handle src, bool convert) {
+ if (!src) {
+ return false;
+ } else if (src.is_none()) {
+ value = {}; // nullopt
+ return true;
+ } else if (!inner.load(src, convert)) {
+ return false;
+ } else {
+ value.emplace(static_cast<const value_type&>(inner));
+ return true;
+ }
+ }
+
+ PYBIND11_TYPE_CASTER(T, _("Optional[") + caster_type::name() + _("]"));
+
+private:
+ caster_type inner;
+};
+
+#if PYBIND11_HAS_OPTIONAL
+template<typename T> struct type_caster<std::optional<T>>
+ : public optional_caster<std::optional<T>> {};
+#endif
+
+#if PYBIND11_HAS_EXP_OPTIONAL
+template<typename T> struct type_caster<std::experimental::optional<T>>
+ : public optional_caster<std::experimental::optional<T>> {};
+#endif
+
NAMESPACE_END(detail)
inline std::ostream &operator<<(std::ostream &os, const handle &obj) {
diff --git a/tests/test_python_types.cpp b/tests/test_python_types.cpp
index 678a56d..6a9e3cf 100644
--- a/tests/test_python_types.cpp
+++ b/tests/test_python_types.cpp
@@ -289,4 +289,18 @@
return d;
});
+
+ // this only tests std::experimental::optional for now
+ bool has_optional = false;
+#ifdef PYBIND11_HAS_EXP_OPTIONAL
+ has_optional = true;
+ using opt_int = std::experimental::optional<int>;
+ m.def("double_or_zero", [](const opt_int& x) -> int {
+ return x.value_or(0) * 2;
+ });
+ m.def("half_or_none", [](int x) -> opt_int {
+ return x ? opt_int(x / 2) : opt_int();
+ });
+#endif
+ m.attr("has_optional") = py::cast(has_optional);
});
diff --git a/tests/test_python_types.py b/tests/test_python_types.py
index 9bba824..3a8a09e 100644
--- a/tests/test_python_types.py
+++ b/tests/test_python_types.py
@@ -1,6 +1,6 @@
import pytest
-from pybind11_tests import ExamplePythonTypes, ConstructorStats
+from pybind11_tests import ExamplePythonTypes, ConstructorStats, has_optional
def test_static():
@@ -295,3 +295,16 @@
assert d["set"] == 1
assert d["deferred_set"] == 1
assert d["var"] == 99
+
+
+@pytest.mark.skipif(not has_optional, reason='no <experimental/optional>')
+def test_optional():
+ from pybind11_tests import double_or_zero, half_or_none
+
+ assert double_or_zero(None) == 0
+ assert double_or_zero(42) == 84
+ pytest.raises(TypeError, double_or_zero, 'foo')
+
+ assert half_or_none(0) is None
+ assert half_or_none(42) == 21
+ pytest.raises(TypeError, half_or_none, 'foo')