元組（Tuple）物件
*****************

PyTupleObject

   This subtype of "PyObject" represents a Python tuple object.

PyTypeObject PyTuple_Type

   This instance of "PyTypeObject" represents the Python tuple type;
   it is the same object as "tuple" in the Python layer.

int PyTuple_Check(PyObject *p)

   Return true if *p* is a tuple object or an instance of a subtype of
   the tuple type.

int PyTuple_CheckExact(PyObject *p)

   Return true if *p* is a tuple object, but not an instance of a
   subtype of the tuple type.

PyObject* PyTuple_New(Py_ssize_t len)
    *Return value: New reference.*

   Return a new tuple object of size *len*, or *NULL* on failure.

PyObject* PyTuple_Pack(Py_ssize_t n, ...)
    *Return value: New reference.*

   Return a new tuple object of size *n*, or *NULL* on failure. The
   tuple values are initialized to the subsequent *n* C arguments
   pointing to Python objects. "PyTuple_Pack(2, a, b)" is equivalent
   to "Py_BuildValue("(OO)", a, b)".

Py_ssize_t PyTuple_Size(PyObject *p)

   Take a pointer to a tuple object, and return the size of that
   tuple.

Py_ssize_t PyTuple_GET_SIZE(PyObject *p)

   Return the size of the tuple *p*, which must be non-*NULL* and
   point to a tuple; no error checking is performed.

PyObject* PyTuple_GetItem(PyObject *p, Py_ssize_t pos)
    *Return value: Borrowed reference.*

   Return the object at position *pos* in the tuple pointed to by *p*.
   If *pos* is out of bounds, return *NULL* and sets an "IndexError"
   exception.

PyObject* PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos)
    *Return value: Borrowed reference.*

   Like "PyTuple_GetItem()", but does no checking of its arguments.

PyObject* PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high)
    *Return value: New reference.*

   Take a slice of the tuple pointed to by *p* from *low* to *high*
   and return it as a new tuple.

int PyTuple_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)

   Insert a reference to object *o* at position *pos* of the tuple
   pointed to by *p*. Return "0" on success.

   備註: This function "steals" a reference to *o*.

void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o)

   Like "PyTuple_SetItem()", but does no error checking, and should
   *only* be used to fill in brand new tuples.

   備註: This function "steals" a reference to *o*.

int _PyTuple_Resize(PyObject **p, Py_ssize_t newsize)

   Can be used to resize a tuple.  *newsize* will be the new length of
   the tuple. Because tuples are *supposed* to be immutable, this
   should only be used if there is only one reference to the object.
   Do *not* use this if the tuple may already be known to some other
   part of the code.  The tuple will always grow or shrink at the end.
   Think of this as destroying the old tuple and creating a new one,
   only more efficiently.  Returns "0" on success. Client code should
   never assume that the resulting value of "*p" will be the same as
   before calling this function. If the object referenced by "*p" is
   replaced, the original "*p" is destroyed.  On failure, returns "-1"
   and sets "*p" to *NULL*, and raises "MemoryError" or "SystemError".

int PyTuple_ClearFreeList()

   Clear the free list. Return the total number of freed items.


Struct Sequence Objects
***********************

Struct sequence objects are the C equivalent of "namedtuple()"
objects, i.e. a sequence whose items can also be accessed through
attributes. To create a struct sequence, you first have to create a
specific struct sequence type.

PyTypeObject* PyStructSequence_NewType(PyStructSequence_Desc *desc)
    *Return value: New reference.*

   Create a new struct sequence type from the data in *desc*,
   described below. Instances of the resulting type can be created
   with "PyStructSequence_New()".

void PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)

   Initializes a struct sequence type *type* from *desc* in place.

int PyStructSequence_InitType2(PyTypeObject *type, PyStructSequence_Desc *desc)

   The same as "PyStructSequence_InitType", but returns "0" on success
   and "-1" on failure.

   3.4 版新加入.

PyStructSequence_Desc

   Contains the meta information of a struct sequence type to create.

   +---------------------+--------------------------------+--------------------------------------+
   | Field               | C Type                         | Meaning                              |
   |=====================|================================|======================================|
   | "name"              | "const char *"                 | name of the struct sequence type     |
   +---------------------+--------------------------------+--------------------------------------+
   | "doc"               | "const char *"                 | pointer to docstring for the type or |
   |                     |                                | NULL to omit                         |
   +---------------------+--------------------------------+--------------------------------------+
   | "fields"            | "PyStructSequence_Field *"     | pointer to *NULL*-terminated array   |
   |                     |                                | with field names of the new type     |
   +---------------------+--------------------------------+--------------------------------------+
   | "n_in_sequence"     | "int"                          | number of fields visible to the      |
   |                     |                                | Python side (if used as tuple)       |
   +---------------------+--------------------------------+--------------------------------------+

PyStructSequence_Field

   Describes a field of a struct sequence. As a struct sequence is
   modeled as a tuple, all fields are typed as "PyObject*".  The index
   in the "fields" array of the "PyStructSequence_Desc" determines
   which field of the struct sequence is described.

   +-------------+--------------------+----------------------------------------+
   | Field       | C Type             | Meaning                                |
   |=============|====================|========================================|
   | "name"      | "const char *"     | name for the field or *NULL* to end    |
   |             |                    | the list of named fields, set to       |
   |             |                    | PyStructSequence_UnnamedField to leave |
   |             |                    | unnamed                                |
   +-------------+--------------------+----------------------------------------+
   | "doc"       | "const char *"     | field docstring or *NULL* to omit      |
   +-------------+--------------------+----------------------------------------+

char* PyStructSequence_UnnamedField

   Special value for a field name to leave it unnamed.

PyObject* PyStructSequence_New(PyTypeObject *type)
    *Return value: New reference.*

   Creates an instance of *type*, which must have been created with
   "PyStructSequence_NewType()".

PyObject* PyStructSequence_GetItem(PyObject *p, Py_ssize_t pos)
    *Return value: Borrowed reference.*

   Return the object at position *pos* in the struct sequence pointed
   to by *p*. No bounds checking is performed.

PyObject* PyStructSequence_GET_ITEM(PyObject *p, Py_ssize_t pos)
    *Return value: Borrowed reference.*

   Macro equivalent of "PyStructSequence_GetItem()".

void PyStructSequence_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o)

   Sets the field at index *pos* of the struct sequence *p* to value
   *o*.  Like "PyTuple_SET_ITEM()", this should only be used to fill
   in brand new instances.

   備註: This function "steals" a reference to *o*.

void PyStructSequence_SET_ITEM(PyObject *p, Py_ssize_t *pos, PyObject *o)

   Macro equivalent of "PyStructSequence_SetItem()".

   備註: This function "steals" a reference to *o*.
