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bpo-5945: Improve mappings and sequences C API docs. (GH-7029)

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Serhiy Storchaka 2018-05-22 11:02:44 +03:00 committed by GitHub
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66
Doc/c-api/mapping.rst
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@ -5,11 +5,17 @@
Mapping Protocol
================
See also :c:func:`PyObject_GetItem`, :c:func:`PyObject_SetItem` and
:c:func:`PyObject_DelItem`.
.. c:function:: int PyMapping_Check(PyObject *o)
Return ``1`` if the object provides mapping protocol, and ``0`` otherwise. This
function always succeeds.
Return ``1`` if the object provides mapping protocol or supports slicing,
and ``0`` otherwise. Note that it returns ``1`` for Python classes with
a :meth:`__getitem__` method since in general case it is impossible to
determine what the type of keys it supports. This function always
succeeds.
.. c:function:: Py_ssize_t PyMapping_Size(PyObject *o)
@ -17,35 +23,49 @@ Mapping Protocol
.. index:: builtin: len
Returns the number of keys in object *o* on success, and ``-1`` on failure. For
objects that do not provide mapping protocol, this is equivalent to the Python
expression ``len(o)``.
Returns the number of keys in object *o* on success, and ``-1`` on failure.
This is equivalent to the Python expression ``len(o)``.
.. c:function:: int PyMapping_DelItemString(PyObject *o, const char *key)
.. c:function:: PyObject* PyMapping_GetItemString(PyObject *o, const char *key)
Remove the mapping for object *key* from the object *o*. Return ``-1`` on
failure. This is equivalent to the Python statement ``del o[key]``.
Return element of *o* corresponding to the string *key* or *NULL* on failure.
This is the equivalent of the Python expression ``o[key]``.
See also :c:func:`PyObject_GetItem`.
.. c:function:: int PyMapping_SetItemString(PyObject *o, const char *key, PyObject *v)
Map the string *key* to the value *v* in object *o*. Returns ``-1`` on
failure. This is the equivalent of the Python statement ``o[key] = v``.
See also :c:func:`PyObject_SetItem`.
.. c:function:: int PyMapping_DelItem(PyObject *o, PyObject *key)
Remove the mapping for object *key* from the object *o*. Return ``-1`` on
failure. This is equivalent to the Python statement ``del o[key]``.
Remove the mapping for the object *key* from the object *o*. Return ``-1``
on failure. This is equivalent to the Python statement ``del o[key]``.
This is an alias of :c:func:`PyObject_DelItem`.
.. c:function:: int PyMapping_HasKeyString(PyObject *o, const char *key)
.. c:function:: int PyMapping_DelItemString(PyObject *o, const char *key)
On success, return ``1`` if the mapping object has the key *key* and ``0``
otherwise. This is equivalent to the Python expression ``key in o``.
This function always succeeds.
Remove the mapping for the string *key* from the object *o*. Return ``-1``
on failure. This is equivalent to the Python statement ``del o[key]``.
.. c:function:: int PyMapping_HasKey(PyObject *o, PyObject *key)
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise. This
is equivalent to the Python expression ``key in o``. This function always
succeeds.
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.
This is equivalent to the Python expression ``key in o``.
This function always succeeds.
.. c:function:: int PyMapping_HasKeyString(PyObject *o, const char *key)
Return ``1`` if the mapping object has the key *key* and ``0`` otherwise.
This is equivalent to the Python expression ``key in o``.
This function always succeeds.
.. c:function:: PyObject* PyMapping_Keys(PyObject *o)
@ -73,15 +93,3 @@ Mapping Protocol
.. versionchanged:: 3.7
Previously, the function returned a list or a tuple.
.. c:function:: PyObject* PyMapping_GetItemString(PyObject *o, const char *key)
Return element of *o* corresponding to the object *key* or *NULL* on failure.
This is the equivalent of the Python expression ``o[key]``.
.. c:function:: int PyMapping_SetItemString(PyObject *o, const char *key, PyObject *v)
Map the object *key* to the value *v* in object *o*. Returns ``-1`` on failure.
This is the equivalent of the Python statement ``o[key] = v``.

8
Doc/c-api/object.rst
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@ -379,8 +379,8 @@ Object Protocol
parameters must be non-*NULL*.
.. c:function:: Py_ssize_t PyObject_Length(PyObject *o)
Py_ssize_t PyObject_Size(PyObject *o)
.. c:function:: Py_ssize_t PyObject_Size(PyObject *o)
Py_ssize_t PyObject_Length(PyObject *o)
.. index:: builtin: len
@ -414,8 +414,8 @@ Object Protocol
.. c:function:: int PyObject_DelItem(PyObject *o, PyObject *key)
Delete the mapping for *key* from *o*. Returns ``-1`` on failure. This is the
equivalent of the Python statement ``del o[key]``.
Remove the mapping for the object *key* from the object *o*. Return ``-1``
on failure. This is equivalent to the Python statement ``del o[key]``.
.. c:function:: PyObject* PyObject_Dir(PyObject *o)

31
Doc/c-api/sequence.rst
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@ -9,7 +9,10 @@ Sequence Protocol
.. c:function:: int PySequence_Check(PyObject *o)
Return ``1`` if the object provides sequence protocol, and ``0`` otherwise.
This function always succeeds.
Note that it returns ``1`` for Python classes with a :meth:`__getitem__`
method unless they are :class:`dict` subclasses since in general case it
is impossible to determine what the type of keys it supports. This
function always succeeds.
.. c:function:: Py_ssize_t PySequence_Size(PyObject *o)
@ -119,18 +122,27 @@ Sequence Protocol
.. index:: builtin: tuple
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,
Return a tuple object with the same contents as the sequence or iterable *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)``.
.. c:function:: PyObject* PySequence_Fast(PyObject *o, const char *m)
Return the sequence *o* as a list, unless it is already a tuple or list, in
Return the sequence or iterable *o* as a list, unless it is already a tuple or list, in
which case *o* is returned. Use :c:func:`PySequence_Fast_GET_ITEM` to access
the members of the result. Returns *NULL* on failure. If the object is not
a sequence, raises :exc:`TypeError` with *m* as the message text.
a sequence or iterable, raises :exc:`TypeError` with *m* as the message text.
.. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)
Returns the length of *o*, assuming that *o* was returned by
:c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be
gotten by calling :c:func:`PySequence_Size` on *o*, but
:c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list
or tuple.
.. c:function:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i)
@ -155,12 +167,3 @@ Sequence Protocol
:c:func:`PySequence_GetItem` but without checking that
:c:func:`PySequence_Check` on *o* is true and without adjustment for negative
indices.
.. c:function:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o)
Returns the length of *o*, assuming that *o* was returned by
:c:func:`PySequence_Fast` and that *o* is not *NULL*. The size can also be
gotten by calling :c:func:`PySequence_Size` on *o*, but
:c:func:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list
or tuple.

56
Doc/c-api/typeobj.rst
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@ -1167,21 +1167,24 @@ Mapping Object Structures
.. c:member:: lenfunc PyMappingMethods.mp_length
This function is used by :c:func:`PyMapping_Length` and
This function is used by :c:func:`PyMapping_Size` and
:c:func:`PyObject_Size`, and has the same signature. This slot may be set to
*NULL* if the object has no defined length.
.. c:member:: binaryfunc PyMappingMethods.mp_subscript
This function is used by :c:func:`PyObject_GetItem` and has the same
signature. This slot must be filled for the :c:func:`PyMapping_Check`
function to return ``1``, it can be *NULL* otherwise.
This function is used by :c:func:`PyObject_GetItem` and
:c:func:`PySequence_GetSlice`, and has the same signature as
:c:func:`!PyObject_GetItem`. This slot must be filled for the
:c:func:`PyMapping_Check` function to return ``1``, it can be *NULL*
otherwise.
.. c:member:: objobjargproc PyMappingMethods.mp_ass_subscript
This function is used by :c:func:`PyObject_SetItem` and
:c:func:`PyObject_DelItem`. It has the same signature as
:c:func:`PyObject_SetItem`, but *v* can also be set to *NULL* to delete
This function is used by :c:func:`PyObject_SetItem`,
:c:func:`PyObject_DelItem`, :c:func:`PyObject_SetSlice` and
:c:func:`PyObject_DelSlice`. It has the same signature as
:c:func:`!PyObject_SetItem`, but *v* can also be set to *NULL* to delete
an item. If this slot is *NULL*, the object does not support item
assignment and deletion.
@ -1201,26 +1204,29 @@ Sequence Object Structures
.. c:member:: lenfunc PySequenceMethods.sq_length
This function is used by :c:func:`PySequence_Size` and :c:func:`PyObject_Size`,
and has the same signature.
This function is used by :c:func:`PySequence_Size` and
:c:func:`PyObject_Size`, and has the same signature. It is also used for
handling negative indices via the :c:member:`~PySequenceMethods.sq_item`
and the :c:member:`~PySequenceMethods.sq_ass_item` slots.
.. c:member:: binaryfunc PySequenceMethods.sq_concat
This function is used by :c:func:`PySequence_Concat` and has the same
signature. It is also used by the ``+`` operator, after trying the numeric
addition via the :c:member:`~PyTypeObject.tp_as_number.nb_add` slot.
addition via the :c:member:`~PyNumberMethods.nb_add` slot.
.. c:member:: ssizeargfunc PySequenceMethods.sq_repeat
This function is used by :c:func:`PySequence_Repeat` and has the same
signature. It is also used by the ``*`` operator, after trying numeric
multiplication via the :c:member:`~PyTypeObject.tp_as_number.nb_multiply`
slot.
multiplication via the :c:member:`~PyNumberMethods.nb_multiply` slot.
.. c:member:: ssizeargfunc PySequenceMethods.sq_item
This function is used by :c:func:`PySequence_GetItem` and has the same
signature. This slot must be filled for the :c:func:`PySequence_Check`
signature. It is also used by :c:func:`PyObject_GetItem`, after trying
the subscription via the :c:member:`~PyMappingMethods.mp_subscript` slot.
This slot must be filled for the :c:func:`PySequence_Check`
function to return ``1``, it can be *NULL* otherwise.
Negative indexes are handled as follows: if the :attr:`sq_length` slot is
@ -1231,28 +1237,36 @@ Sequence Object Structures
.. c:member:: ssizeobjargproc PySequenceMethods.sq_ass_item
This function is used by :c:func:`PySequence_SetItem` and has the same
signature. This slot may be left to *NULL* if the object does not support
signature. It is also used by :c:func:`PyObject_SetItem` and
:c:func:`PyObject_DelItem`, after trying the item assignment and deletion
via the :c:member:`~PyMappingMethods.mp_ass_subscript` slot.
This slot may be left to *NULL* if the object does not support
item assignment and deletion.
.. c:member:: objobjproc PySequenceMethods.sq_contains
This function may be used by :c:func:`PySequence_Contains` and has the same
signature. This slot may be left to *NULL*, in this case
:c:func:`PySequence_Contains` simply traverses the sequence until it finds a
match.
:c:func:`!PySequence_Contains` simply traverses the sequence until it
finds a match.
.. c:member:: binaryfunc PySequenceMethods.sq_inplace_concat
This function is used by :c:func:`PySequence_InPlaceConcat` and has the same
signature. It should modify its first operand, and return it.
signature. It should modify its first operand, and return it. This slot
may be left to *NULL*, in this case :c:func:`!PySequence_InPlaceConcat`
will fall back to :c:func:`PySequence_Concat`. It is also used by the
augmented assignment ``+=``, after trying numeric inplace addition
via the :c:member:`~PyNumberMethods.nb_inplace_add` slot.
.. c:member:: ssizeargfunc PySequenceMethods.sq_inplace_repeat
This function is used by :c:func:`PySequence_InPlaceRepeat` and has the same
signature. It should modify its first operand, and return it.
.. XXX need to explain precedence between mapping and sequence
.. XXX explains when to implement the sq_inplace_* slots
signature. It should modify its first operand, and return it. This slot
may be left to *NULL*, in this case :c:func:`!PySequence_InPlaceRepeat`
will fall back to :c:func:`PySequence_Repeat`. It is also used by the
augmented assignment ``*=``, after trying numeric inplace multiplication
via the :c:member:`~PyNumberMethods.nb_inplace_multiply` slot.
.. _buffer-structs:

16
Include/abstract.h
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@ -442,13 +442,14 @@ PyAPI_FUNC(PyObject *) PyObject_GetItem(PyObject *o, PyObject *key);
This is the equivalent of the Python statement: o[key]=v. */
PyAPI_FUNC(int) PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v);
/* Remove the mapping for object, key, from the object 'o'.
/* Remove the mapping for the string 'key' from the object 'o'.
Returns -1 on failure.
This is equivalent to the Python statement: del o[key]. */
PyAPI_FUNC(int) PyObject_DelItemString(PyObject *o, const char *key);
/* Delete the mapping for key from object 'o'. Returns -1 on failure.
/* Delete the mapping for the object 'key' from the object 'o'.
Returns -1 on failure.
This is the equivalent of the Python statement: del o[key]. */
PyAPI_FUNC(int) PyObject_DelItem(PyObject *o, PyObject *key);
@ -1005,8 +1006,7 @@ PyAPI_FUNC(PyObject *) PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count);
PyAPI_FUNC(int) PyMapping_Check(PyObject *o);
/* Returns the number of keys in mapping object 'o' on success, and -1 on
failure. For objects that do not provide sequence protocol, this is
equivalent to the Python expression: len(o). */
failure. This is equivalent to the Python expression: len(o). */
PyAPI_FUNC(Py_ssize_t) PyMapping_Size(PyObject *o);
/* For DLL compatibility */
@ -1019,7 +1019,7 @@ PyAPI_FUNC(Py_ssize_t) PyMapping_Length(PyObject *o);
int PyMapping_DelItemString(PyObject *o, const char *key);
Remove the mapping for object 'key' from the mapping 'o'. Returns -1 on
Remove the mapping for the string 'key' from the mapping 'o'. Returns -1 on
failure.
This is equivalent to the Python statement: del o[key]. */
@ -1029,7 +1029,7 @@ PyAPI_FUNC(Py_ssize_t) PyMapping_Length(PyObject *o);
int PyMapping_DelItem(PyObject *o, PyObject *key);
Remove the mapping for object 'key' from the mapping object 'o'.
Remove the mapping for the object 'key' from the mapping object 'o'.
Returns -1 on failure.
This is equivalent to the Python statement: del o[key]. */
@ -1063,13 +1063,13 @@ PyAPI_FUNC(PyObject *) PyMapping_Values(PyObject *o);
NULL. */
PyAPI_FUNC(PyObject *) PyMapping_Items(PyObject *o);
/* Return element of o corresponding to the object, key, or NULL on failure.
/* Return element of 'o' corresponding to the string 'key' or NULL on failure.
This is the equivalent of the Python expression: o[key]. */
PyAPI_FUNC(PyObject *) PyMapping_GetItemString(PyObject *o,
const char *key);
/* Map the object 'key' to the value 'v' in the mapping 'o'.
/* Map the string 'key' to the value 'v' in the mapping 'o'.
Returns -1 on failure.
This is the equivalent of the Python statement: o[key]=v. */