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+Python types
+############
+
+.. _wrappers:
+
+Available wrappers
+==================
+
+All major Python types are available as thin C++ wrapper classes. These
+can also be used as function parameters -- see :ref:`python_objects_as_args`.
+
+Available types include :class:`handle`, :class:`object`, :class:`bool_`,
+:class:`int_`, :class:`float_`, :class:`str`, :class:`bytes`, :class:`tuple`,
+:class:`list`, :class:`dict`, :class:`slice`, :class:`none`, :class:`capsule`,
+:class:`iterable`, :class:`iterator`, :class:`function`, :class:`buffer`,
+:class:`array`, and :class:`array_t`.
+
+.. warning::
+
+    Be sure to review the :ref:`pytypes_gotchas` before using this heavily in
+    your C++ API.
+
+.. _instantiating_compound_types:
+
+Instantiating compound Python types from C++
+============================================
+
+Dictionaries can be initialized in the :class:`dict` constructor:
+
+.. code-block:: cpp
+
+    using namespace pybind11::literals; // to bring in the `_a` literal
+    py::dict d("spam"_a=py::none(), "eggs"_a=42);
+
+A tuple of python objects can be instantiated using :func:`py::make_tuple`:
+
+.. code-block:: cpp
+
+    py::tuple tup = py::make_tuple(42, py::none(), "spam");
+
+Each element is converted to a supported Python type.
+
+A `simple namespace`_ can be instantiated using
+
+.. code-block:: cpp
+
+    using namespace pybind11::literals;  // to bring in the `_a` literal
+    py::object SimpleNamespace = py::module_::import("types").attr("SimpleNamespace");
+    py::object ns = SimpleNamespace("spam"_a=py::none(), "eggs"_a=42);
+
+Attributes on a namespace can be modified with the :func:`py::delattr`,
+:func:`py::getattr`, and :func:`py::setattr` functions. Simple namespaces can
+be useful as lightweight stand-ins for class instances.
+
+.. _simple namespace: https://docs.python.org/3/library/types.html#types.SimpleNamespace
+
+.. _casting_back_and_forth:
+
+Casting back and forth
+======================
+
+In this kind of mixed code, it is often necessary to convert arbitrary C++
+types to Python, which can be done using :func:`py::cast`:
+
+.. code-block:: cpp
+
+    MyClass *cls = ...;
+    py::object obj = py::cast(cls);
+
+The reverse direction uses the following syntax:
+
+.. code-block:: cpp
+
+    py::object obj = ...;
+    MyClass *cls = obj.cast<MyClass *>();
+
+When conversion fails, both directions throw the exception :class:`cast_error`.
+
+.. _python_libs:
+
+Accessing Python libraries from C++
+===================================
+
+It is also possible to import objects defined in the Python standard
+library or available in the current Python environment (``sys.path``) and work
+with these in C++.
+
+This example obtains a reference to the Python ``Decimal`` class.
+
+.. code-block:: cpp
+
+    // Equivalent to "from decimal import Decimal"
+    py::object Decimal = py::module_::import("decimal").attr("Decimal");
+
+.. code-block:: cpp
+
+    // Try to import scipy
+    py::object scipy = py::module_::import("scipy");
+    return scipy.attr("__version__");
+
+
+.. _calling_python_functions:
+
+Calling Python functions
+========================
+
+It is also possible to call Python classes, functions and methods
+via ``operator()``.
+
+.. code-block:: cpp
+
+    // Construct a Python object of class Decimal
+    py::object pi = Decimal("3.14159");
+
+.. code-block:: cpp
+
+    // Use Python to make our directories
+    py::object os = py::module_::import("os");
+    py::object makedirs = os.attr("makedirs");
+    makedirs("/tmp/path/to/somewhere");
+
+One can convert the result obtained from Python to a pure C++ version
+if a ``py::class_`` or type conversion is defined.
+
+.. code-block:: cpp
+
+    py::function f = <...>;
+    py::object result_py = f(1234, "hello", some_instance);
+    MyClass &result = result_py.cast<MyClass>();
+
+.. _calling_python_methods:
+
+Calling Python methods
+========================
+
+To call an object's method, one can again use ``.attr`` to obtain access to the
+Python method.
+
+.. code-block:: cpp
+
+    // Calculate e^π in decimal
+    py::object exp_pi = pi.attr("exp")();
+    py::print(py::str(exp_pi));
+
+In the example above ``pi.attr("exp")`` is a *bound method*: it will always call
+the method for that same instance of the class. Alternately one can create an
+*unbound method* via the Python class (instead of instance) and pass the ``self``
+object explicitly, followed by other arguments.
+
+.. code-block:: cpp
+
+    py::object decimal_exp = Decimal.attr("exp");
+
+    // Compute the e^n for n=0..4
+    for (int n = 0; n < 5; n++) {
+        py::print(decimal_exp(Decimal(n));
+    }
+
+Keyword arguments
+=================
+
+Keyword arguments are also supported. In Python, there is the usual call syntax:
+
+.. code-block:: python
+
+    def f(number, say, to):
+        ...  # function code
+
+
+    f(1234, say="hello", to=some_instance)  # keyword call in Python
+
+In C++, the same call can be made using:
+
+.. code-block:: cpp
+
+    using namespace pybind11::literals; // to bring in the `_a` literal
+    f(1234, "say"_a="hello", "to"_a=some_instance); // keyword call in C++
+
+Unpacking arguments
+===================
+
+Unpacking of ``*args`` and ``**kwargs`` is also possible and can be mixed with
+other arguments:
+
+.. code-block:: cpp
+
+    // * unpacking
+    py::tuple args = py::make_tuple(1234, "hello", some_instance);
+    f(*args);
+
+    // ** unpacking
+    py::dict kwargs = py::dict("number"_a=1234, "say"_a="hello", "to"_a=some_instance);
+    f(**kwargs);
+
+    // mixed keywords, * and ** unpacking
+    py::tuple args = py::make_tuple(1234);
+    py::dict kwargs = py::dict("to"_a=some_instance);
+    f(*args, "say"_a="hello", **kwargs);
+
+Generalized unpacking according to PEP448_ is also supported:
+
+.. code-block:: cpp
+
+    py::dict kwargs1 = py::dict("number"_a=1234);
+    py::dict kwargs2 = py::dict("to"_a=some_instance);
+    f(**kwargs1, "say"_a="hello", **kwargs2);
+
+.. seealso::
+
+    The file :file:`tests/test_pytypes.cpp` contains a complete
+    example that demonstrates passing native Python types in more detail. The
+    file :file:`tests/test_callbacks.cpp` presents a few examples of calling
+    Python functions from C++, including keywords arguments and unpacking.
+
+.. _PEP448: https://www.python.org/dev/peps/pep-0448/
+
+.. _implicit_casting:
+
+Implicit casting
+================
+
+When using the C++ interface for Python types, or calling Python functions,
+objects of type :class:`object` are returned. It is possible to invoke implicit
+conversions to subclasses like :class:`dict`. The same holds for the proxy objects
+returned by ``operator[]`` or ``obj.attr()``.
+Casting to subtypes improves code readability and allows values to be passed to
+C++ functions that require a specific subtype rather than a generic :class:`object`.
+
+.. code-block:: cpp
+
+    #include <pybind11/numpy.h>
+    using namespace pybind11::literals;
+
+    py::module_ os = py::module_::import("os");
+    py::module_ path = py::module_::import("os.path");  // like 'import os.path as path'
+    py::module_ np = py::module_::import("numpy");  // like 'import numpy as np'
+
+    py::str curdir_abs = path.attr("abspath")(path.attr("curdir"));
+    py::print(py::str("Current directory: ") + curdir_abs);
+    py::dict environ = os.attr("environ");
+    py::print(environ["HOME"]);
+    py::array_t<float> arr = np.attr("ones")(3, "dtype"_a="float32");
+    py::print(py::repr(arr + py::int_(1)));
+
+These implicit conversions are available for subclasses of :class:`object`; there
+is no need to call ``obj.cast()`` explicitly as for custom classes, see
+:ref:`casting_back_and_forth`.
+
+.. note::
+    If a trivial conversion via move constructor is not possible, both implicit and
+    explicit casting (calling ``obj.cast()``) will attempt a "rich" conversion.
+    For instance, ``py::list env = os.attr("environ");`` will succeed and is
+    equivalent to the Python code ``env = list(os.environ)`` that produces a
+    list of the dict keys.
+
+..  TODO: Adapt text once PR #2349 has landed
+
+Handling exceptions
+===================
+
+Python exceptions from wrapper classes will be thrown as a ``py::error_already_set``.
+See :ref:`Handling exceptions from Python in C++
+<handling_python_exceptions_cpp>` for more information on handling exceptions
+raised when calling C++ wrapper classes.
+
+.. _pytypes_gotchas:
+
+Gotchas
+=======
+
+Default-Constructed Wrappers
+----------------------------
+
+When a wrapper type is default-constructed, it is **not** a valid Python object (i.e. it is not ``py::none()``). It is simply the same as
+``PyObject*`` null pointer. To check for this, use
+``static_cast<bool>(my_wrapper)``.
+
+Assigning py::none() to wrappers
+--------------------------------
+
+You may be tempted to use types like ``py::str`` and ``py::dict`` in C++
+signatures (either pure C++, or in bound signatures), and assign them default
+values of ``py::none()``. However, in a best case scenario, it will fail fast
+because ``None`` is not convertible to that type (e.g. ``py::dict``), or in a
+worse case scenario, it will silently work but corrupt the types you want to
+work with (e.g. ``py::str(py::none())`` will yield ``"None"`` in Python).