
Sequence Protocol
*****************

int PySequence_Check(PyObject *o)

   Return ``1`` if the object provides sequence protocol, and ``0``
   otherwise. This function always succeeds.

Py_ssize_t PySequence_Size(PyObject *o)
Py_ssize_t PySequence_Length(PyObject *o)

   Returns the number of objects in sequence *o* on success, and
   ``-1`` on failure. For objects that do not provide sequence
   protocol, this is equivalent to the Python expression ``len(o)``.

PyObject* PySequence_Concat(PyObject *o1, PyObject *o2)
    Return value: New reference.

   Return the concatenation of *o1* and *o2* on success, and *NULL* on
   failure. This is the equivalent of the Python expression ``o1 +
   o2``.

PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count)
    Return value: New reference.

   Return the result of repeating sequence object *o* *count* times,
   or *NULL* on failure.  This is the equivalent of the Python
   expression ``o * count``.

PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2)
    Return value: New reference.

   Return the concatenation of *o1* and *o2* on success, and *NULL* on
   failure. The operation is done *in-place* when *o1* supports it.
   This is the equivalent of the Python expression ``o1 += o2``.

PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count)
    Return value: New reference.

   Return the result of repeating sequence object *o* *count* times,
   or *NULL* on failure.  The operation is done *in-place* when *o*
   supports it.  This is the equivalent of the Python expression ``o
   *= count``.

PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i)
    Return value: New reference.

   Return the *i*th element of *o*, or *NULL* on failure. This is the
   equivalent of the Python expression ``o[i]``.

PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)
    Return value: New reference.

   Return the slice of sequence object *o* between *i1* and *i2*, or
   *NULL* on failure. This is the equivalent of the Python expression
   ``o[i1:i2]``.

int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v)

   Assign object *v* to the *i*th element of *o*.  Returns ``-1`` on
   failure.  This is the equivalent of the Python statement ``o[i] =
   v``.  This function *does not* steal a reference to *v*.

int PySequence_DelItem(PyObject *o, Py_ssize_t i)

   Delete the *i*th element of object *o*.  Returns ``-1`` on failure.
   This is the equivalent of the Python statement ``del o[i]``.

int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v)

   Assign the sequence object *v* to the slice in sequence object *o*
   from *i1* to *i2*.  This is the equivalent of the Python statement
   ``o[i1:i2] = v``.

int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2)

   Delete the slice in sequence object *o* from *i1* to *i2*.  Returns
   ``-1`` on failure.  This is the equivalent of the Python statement
   ``del o[i1:i2]``.

Py_ssize_t PySequence_Count(PyObject *o, PyObject *value)

   Return the number of occurrences of *value* in *o*, that is, return
   the number of keys for which ``o[key] == value``.  On failure,
   return ``-1``.  This is equivalent to the Python expression
   ``o.count(value)``.

int PySequence_Contains(PyObject *o, PyObject *value)

   Determine if *o* contains *value*.  If an item in *o* is equal to
   *value*, return ``1``, otherwise return ``0``. On error, return
   ``-1``.  This is equivalent to the Python expression ``value in
   o``.

Py_ssize_t PySequence_Index(PyObject *o, PyObject *value)

   Return the first index *i* for which ``o[i] == value``.  On error,
   return ``-1``.    This is equivalent to the Python expression
   ``o.index(value)``.

PyObject* PySequence_List(PyObject *o)
    Return value: New reference.

   Return a list object with the same contents as the arbitrary
   sequence *o*.  The returned list is guaranteed to be new.

PyObject* PySequence_Tuple(PyObject *o)
    Return value: New reference.

   Return a tuple object with the same contents as the arbitrary
   sequence *o* or *NULL* on failure.  If *o* is a tuple, a new
   reference will be returned, otherwise a tuple will be constructed
   with the appropriate contents.  This is equivalent to the Python
   expression ``tuple(o)``.

PyObject* PySequence_Fast(PyObject *o, const char *m)
    Return value: New reference.

   Returns the sequence *o* as a tuple, unless it is already a tuple
   or list, in which case *o* is returned.  Use
   ``PySequence_Fast_GET_ITEM()`` to access the members of the result.
   Returns *NULL* on failure.  If the object is not a sequence, raises
   ``TypeError`` with *m* as the message text.

PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)
    Return value: Borrowed reference.

   Return the *i*th element of *o*, assuming that *o* was returned by
   ``PySequence_Fast()``, *o* is not *NULL*, and that *i* is within
   bounds.

PyObject** PySequence_Fast_ITEMS(PyObject *o)

   Return the underlying array of PyObject pointers.  Assumes that *o*
   was returned by ``PySequence_Fast()`` and *o* is not *NULL*.

   Note, if a list gets resized, the reallocation may relocate the
   items array. So, only use the underlying array pointer in contexts
   where the sequence cannot change.

PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i)
    Return value: New reference.

   Return the *i*th element of *o* or *NULL* on failure. Macro form of
   ``PySequence_GetItem()`` but without checking that
   ``PySequence_Check(o)()`` is true and without adjustment for
   negative indices.

Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)

   Returns the length of *o*, assuming that *o* was returned by
   ``PySequence_Fast()`` and that *o* is not *NULL*.  The size can
   also be gotten by calling ``PySequence_Size()`` on *o*, but
   ``PySequence_Fast_GET_SIZE()`` is faster because it can assume *o*
   is a list or tuple.
