# デスクリプタオブジェクト (descriptor object)

"デスクリプタ (descriptor)" は、あるオブジェクトのいくつかの属性について記述したオブジェクトです。デスクリプタオブジェクトは型オブジェクトの辞書内にあります。

PyTypeObject PyProperty_Type
  次に属します: Stable ABI.

  The type object for the built-in descriptor types.

PyObject *PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset)
  戻り値: 新しい参照。 次に属します: Stable ABI.

  Create a new get-set descriptor for extension type type from the `PyGetSetDef` structure getset.

  Get-set descriptors expose attributes implemented by C getter and setter functions rather than stored directly in the instance. This is the same kind of descriptor created for entries in `tp_getset`, and it appears in Python as a `types.GetSetDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyObject *PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *member)
  戻り値: 新しい参照。 次に属します: Stable ABI.

  Create a new member descriptor for extension type type from the `PyMemberDef` structure member.

  Member descriptors expose fields in the type's C struct as Python attributes. This is the same kind of descriptor created for entries in `tp_members`, and it appears in Python as a `types.MemberDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyMemberDescr_Type
  次に属します: Stable ABI.

  The type object for member descriptor objects created from `PyMemberDef` structures. These descriptors expose fields of a C struct as attributes on a type, and correspond to `types.MemberDescriptorType` objects in Python.

PyTypeObject PyGetSetDescr_Type
  次に属します: Stable ABI.

  The type object for get/set descriptor objects created from `PyGetSetDef` structures. These descriptors implement attributes whose value is computed by C getter and setter functions, and are used for many built-in type attributes. They correspond to `types.GetSetDescriptorType` objects in Python.

PyObject *PyDescr_NewMethod(PyTypeObject *type, struct PyMethodDef *meth)
  戻り値: 新しい参照。 次に属します: Stable ABI.

  Create a new method descriptor for extension type type from the `PyMethodDef` structure meth.

  Method descriptors expose C functions as methods on a type. This is the same kind of descriptor created for entries in `tp_methods`, and it appears in Python as a `types.MethodDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyMethodDescr_Type
  次に属します: Stable ABI.

  The type object for method descriptor objects created from `PyMethodDef` structures. These descriptors expose C functions as methods on a type, and correspond to `types.MethodDescriptorType` objects in Python.

struct wrapperbase

  Describes a slot wrapper used by `PyDescr_NewWrapper()`.

  Each `wrapperbase` record stores the Python-visible name and metadata for a special method implemented by a type slot, together with the wrapper function used to adapt that slot to Python's calling convention.

PyObject *PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
  戻り値: 新しい参照。

  Create a new wrapper descriptor for extension type type from the `wrapperbase` structure base and the wrapped slot function pointer wrapped.

  Wrapper descriptors expose special methods implemented by type slots. This is the same kind of descriptor that CPython creates for slot-based special methods such as `__repr__` or `__add__`, and it appears in Python as a `types.WrapperDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyWrapperDescr_Type
  次に属します: Stable ABI.

  The type object for wrapper descriptor objects created by `PyDescr_NewWrapper()` and `PyWrapper_New()`. Wrapper descriptors are used internally to expose special methods implemented via wrapper structures, and appear in Python as `types.WrapperDescriptorType` objects.

PyObject *PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
  戻り値: 新しい参照。 次に属します: Stable ABI.

  Create a new class method descriptor for extension type type from the `PyMethodDef` structure method.

  Class method descriptors expose C methods that receive the class rather than an instance when accessed. This is the same kind of descriptor created for `METH_CLASS` entries in `tp_methods`, and it appears in Python as a `types.ClassMethodDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

int PyDescr_IsData(PyObject *descr)

  Return non-zero if the descriptor object descr describes a data attribute, or `0` if it describes a method. descr must be a descriptor object; there is no error checking.

PyObject *PyWrapper_New(PyObject *d, PyObject *self)
  戻り値: 新しい参照。 次に属します: Stable ABI.

  Create a new bound wrapper object from the wrapper descriptor d and the instance self.

  This is the bound form of a wrapper descriptor created by `PyDescr_NewWrapper()`. CPython creates these objects when a slot wrapper is accessed through an instance, and they appear in Python as `types.MethodWrapperType` objects.

  On success, return a strong reference to the wrapper object. Return `NULL` with an exception set on failure.

## Built-in descriptors

PyTypeObject PySuper_Type
  次に属します: Stable ABI.

  The type object for super objects. This is the same object as `super` in the Python layer.

PyTypeObject PyClassMethod_Type

  The type of class method objects. This is the same object as `classmethod` in the Python layer.

PyTypeObject PyClassMethodDescr_Type
  次に属します: Stable ABI.

  The type object for C-level class method descriptor objects. This is the type of the descriptors created for `classmethod()` defined in C extension types, and corresponds to `types.ClassMethodDescriptorType` objects in Python.

PyObject *PyClassMethod_New(PyObject *callable)

  Create a new `classmethod` object wrapping callable. callable must be a callable object and must not be `NULL`.

  On success, this function returns a strong reference to a new class method descriptor. On failure, this function returns `NULL` with an exception set.

PyTypeObject PyStaticMethod_Type

  The type of static method objects. This is the same object as `staticmethod` in the Python layer.

PyObject *PyStaticMethod_New(PyObject *callable)

  Create a new `staticmethod` object wrapping callable. callable must be a callable object and must not be `NULL`.

  On success, this function returns a strong reference to a new static method descriptor. On failure, this function returns `NULL` with an exception set.