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cpython/Doc/c-api/reflection.rst
Alyssa Coghlan fd6cd621e0
gh-118934: Fix PyEval_GetLocals docs (PEP 667) (#119932)
PEP 667's description of the planned changes to PyEval_GetLocals
was internally inconsistent when accepted, so the docs added for
gh-74929 didn't match either the current behaviour or the intended
behaviour once gh-118934 is fixed.

This PR updates the documentation and 3.13 What's New to match the
intended behaviour (once gh-118934 is fixed).

It also tidies up lingering references to `f_locals` always being a
dictionary (this hasn't been true since at least when custom
namespace support for class statement execution was added)
2024-06-02 04:44:29 +00:00

107 lines
3.7 KiB
ReStructuredText

.. highlight:: c
.. _reflection:
Reflection
==========
.. c:function:: PyObject* PyEval_GetBuiltins(void)
.. deprecated:: 3.13
Use :c:func:`PyEval_GetFrameBuiltins` instead.
Return a dictionary of the builtins in the current execution frame,
or the interpreter of the thread state if no frame is currently executing.
.. c:function:: PyObject* PyEval_GetLocals(void)
.. deprecated:: 3.13
Use either :c:func:`PyEval_GetFrameLocals` to obtain the same behaviour as calling
:func:`locals` in Python code, or else call :c:func:`PyFrame_GetLocals` on the result
of :c:func:`PyEval_GetFrame` to access the :attr:`~frame.f_locals` attribute of the
currently executing frame.
Return a mapping providing access to the local variables in the current execution frame,
or ``NULL`` if no frame is currently executing.
Refer to :func:`locals` for details of the mapping returned at different scopes.
As this function returns a :term:`borrowed reference`, the dictionary returned for
:term:`optimized scopes <optimized scope>` is cached on the frame object and will remain
alive as long as the frame object does. Unlike :c:func:`PyEval_GetFrameLocals` and
:func:`locals`, subsequent calls to this function in the same frame will update the
contents of the cached dictionary to reflect changes in the state of the local variables
rather than returning a new snapshot.
.. versionchanged:: 3.13
As part of :pep:`667`, :c:func:`PyFrame_GetLocals`, :func:`locals`, and
:attr:`FrameType.f_locals <frame.f_locals>` no longer make use of the shared cache
dictionary. Refer to the :ref:`What's New entry <whatsnew313-locals-semantics>` for
additional details.
.. c:function:: PyObject* PyEval_GetGlobals(void)
.. deprecated:: 3.13
Use :c:func:`PyEval_GetFrameGlobals` instead.
Return a dictionary of the global variables in the current execution frame,
or ``NULL`` if no frame is currently executing.
.. c:function:: PyFrameObject* PyEval_GetFrame(void)
Return the current thread state's frame, which is ``NULL`` if no frame is
currently executing.
See also :c:func:`PyThreadState_GetFrame`.
.. c:function:: PyObject* PyEval_GetFrameBuiltins(void)
Return a dictionary of the builtins in the current execution frame,
or the interpreter of the thread state if no frame is currently executing.
.. versionadded:: 3.13
.. c:function:: PyObject* PyEval_GetFrameLocals(void)
Return a dictionary of the local variables in the current execution frame,
or ``NULL`` if no frame is currently executing. Equivalent to calling
:func:`locals` in Python code.
To access :attr:`~frame.f_locals` on the current frame without making an independent
snapshot in :term:`optimized scopes <optimized scope>`, call :c:func:`PyFrame_GetLocals`
on the result of :c:func:`PyEval_GetFrame`.
.. versionadded:: 3.13
.. c:function:: PyObject* PyEval_GetFrameGlobals(void)
Return a dictionary of the global variables in the current execution frame,
or ``NULL`` if no frame is currently executing. Equivalent to calling
:func:`globals` in Python code.
.. versionadded:: 3.13
.. c:function:: const char* PyEval_GetFuncName(PyObject *func)
Return the name of *func* if it is a function, class or instance object, else the
name of *func*\s type.
.. c:function:: const char* PyEval_GetFuncDesc(PyObject *func)
Return a description string, depending on the type of *func*.
Return values include "()" for functions and methods, " constructor",
" instance", and " object". Concatenated with the result of
:c:func:`PyEval_GetFuncName`, the result will be a description of
*func*.