Sep 26, 2024 · May 21, 2024 · May 21, 2024 · May 21, 2024 · May 21, 2024 · May 21, 2024
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst

 .. function:: partial(func, /, *args, **keywords)

   Return a new :ref:`partial object<partial-objects>` which when called
   Return a new :ref:`partial object<partial-objects>` which when called
   will behave like *func* called with the positional arguments *args*
   and keyword arguments *keywords*. If more arguments are supplied to the
   call, they are appended to *args*. If additional keyword arguments are

   If :data:`Placeholder` sentinels are present in *args*, they will be filled first
   when :func:`partial` is called. This allows custom selection of positional arguments
   to be pre-filled when constructing :ref:`partial object<partial-objects>`.
   to be pre-filled when constructing a :ref:`partial object <partial-objects>`.

   If :data:`Placeholder` sentinels are used, all of them must be filled at call time:

      >>> from functools import partial, Placeholder
      >>> say_to_world('Hello', 'dear')
      Hello dear world!

   Calling ``say_to_world('Hello')`` wouldresult in :exc:`TypeError`.
   Calling ``say_to_world('Hello')`` wouldraise a :exc:`TypeError`.

   .. versionchanged:: 3.14
      Support for :data:`Placeholder` in *args*

 .. data:: Placeholder

 This is asingleton objectthat isused as a sentinelfor representing a
   gap in positional arguments when calling :func:`partial`.
 Ithassimilarfeaturesas :data:`None`:
 Asingleton object used as a sentinelto represent a
 "gap" in positional arguments when calling :func:`partial`.
 This objecthas featuressimilar to ``None``:

      >>> type(Placeholder)() is Placeholder
      True
diff --git a/Lib/functools.py b/Lib/functools.py
    The type of the Placeholder singleton.
    Used as a placeholder for partial arguments.
    """
 _singleton = None
 __instance = None

    def __new__(cls):
        if cls._singleton is None:
            cls._singleton = object.__new__(cls)
        return cls._singleton
        if cls.__instance is None:
            cls.__instance = object.__new__(cls)
        return cls.__instance

    def __repr__(self):
        return 'Placeholder'
    def __new__(cls, func, /, *args, **keywords):
        if not callable(func):
            raise TypeError("the first argument must be callable")
 placeholder_count = 0
 np = 0
        nargs = len(args)
        if args:
            while nargs and args[nargs-1] is Placeholder:
            while nargs and args[nargs -1] is Placeholder:
                nargs -= 1
            args = args[:nargs]
 placeholder_count = args.count(Placeholder)
 np = args.count(Placeholder)
        if isinstance(func, partial):
            pargs = func.args
            pnp = func.placeholder_count
                    pos += 1
                if pnp < nargs:
                    all_args.extend(args[pnp:])
 placeholder_count += pnp - end
 np += pnp - end
                args = tuple(all_args)
            else:
 placeholder_count += pnp
 np += pnp
                args = func.args + args
            keywords = {**func.keywords, **keywords}
            func = func.func
        self.func = func
        self.args = args
        self.keywords = keywords
        self.placeholder_count =placeholder_count
        self.placeholder_count =np
        return self

    def __call__(self, /, *args, **keywords):
        keywords = {**self.keywords, **keywords}
        if placeholder_count := self.placeholder_count:
            if len(args) < placeholder_count:
        np = self.placeholder_count
        p_args = self.args
        if np:
            if len(args) < np:
                raise TypeError(
                    "missing positional arguments in 'partial' call; expected "
                    f"at least {placeholder_count}, got {len(args)}")
            f_args = list(self.args)
                    "missing positional arguments "
                    "in 'partial' call; expected "
                    f"at least {np}, got {len(args)}")
            p_args = list(p_args)
            j, pos = 0, 0
            while j <placeholder_count:
                pos =f_args.index(Placeholder, pos)
 f_args[pos] = args[j]
            while j <np:
                pos =p_args.index(Placeholder, pos)
 p_args[pos] = args[j]
                j += 1
                pos += 1
 return self.func(*f_args, *args[j:], **keywords)
 else:
 return self.func(*self.args, *args, **keywords)
 args =args[j:]
 keywords = {**self.keywords, **keywords}
        return self.func(*p_args, *args, **keywords)

    @recursive_repr()
    def __repr__(self):
diff --git a/Misc/NEWS.d/next/Library/2024-05-25-00-54-26.gh-issue-119127.LpPvag.rst b/Misc/NEWS.d/next/Library/2024-05-25-00-54-26.gh-issue-119127.LpPvag.rst
 ``partial``of``functools`` module now supports placeholders for positional
 arguments.
 Positional argumentsof:func:`functools.partial` objects
 now support placeholders via :data:`functools.Placeholder`.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
    /* this object is used delimit args and keywords in the cache keys */
    PyObject *kwd_mark;
    PyTypeObject *placeholder_type;
    PyObject *placeholder;
    PyTypeObject *partial_type;
    PyTypeObject *keyobject_type;
    PyTypeObject *lru_list_elem_type;
        return NULL;
    }

    pto->placeholder =PyObject_CallNoArgs((PyObject *)state->placeholder_type);
    pto->placeholder = state->placeholder;
    Py_ssize_t nnp = 0;
    Py_ssize_t nnargs = PyTuple_GET_SIZE(nargs);
    PyObject *item;
        PyObject *pto_args = pto->args;
        PyObject *item;
        Py_ssize_t j = 0;   // New args index
        for (Py_ssize_t i=0; i < pto_nargs; i++) {
        for (Py_ssize_t i =0; i < pto_nargs; i++) {
            item = PyTuple_GET_ITEM(pto_args, i);
            if (Py_Is(item, pto->placeholder)) {
                item = PyTuple_GET_ITEM(args, j);
    else {
        /* Note: tupleconcat() is optimized for empty tuples */
        args2 = PySequence_Concat(pto->args, args);
 }
 if (args2 == NULL) {
 Py_XDECREF(kwargs2);
 return NULL;
    if (args2 == NULL) {
        Py_XDECREF(kwargs2);
    return NULL;
 }
    }

    PyObject *res = PyObject_Call(pto->fn, args2, kwargs2);
    if (PyModule_AddType(module, state->placeholder_type) < 0) {
        return -1;
    }
    if (PyModule_AddObject(module, "Placeholder", PyObject_CallNoArgs((PyObject *)state->placeholder_type)) < 0) {
    state->placeholder = PyObject_CallNoArgs((PyObject *)state->placeholder_type);
    if (state->placeholder == NULL) {
        return -1;
    }
    if (PyModule_AddObject(module, "Placeholder", state->placeholder) < 0) {
        return -1;
    }
    state->partial_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
Original file line number	Diff line number	Diff line change
Expand Up		@@ -330,7 +330,7 @@ The :mod:`functools` module defines the following functions:

		.. function:: partial(func, /, args, *keywords)

		Return a new :ref:`partial object<partial-objects>` which when called
		Return a new :ref:`partial object<partial-objects>` which when called
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		will behave like func called with the positional arguments args
		and keyword arguments keywords. If more arguments are supplied to the
		call, they are appended to args. If additional keyword arguments are
Expand DownExpand Up		@@ -380,7 +380,8 @@ The :mod:`functools` module defines the following functions:

		If :data:`Placeholder` sentinels are present in args, they will be filled first
		when :func:`partial` is called. This allows custom selection of positional arguments
		to be pre-filled when constructing :ref:`partial object<partial-objects>`.
		to be pre-filled when constructing a :ref:`partial object <partial-objects>`.

		If :data:`Placeholder` sentinels are used, all of them must be filled at call time:
dg-pb marked this conversation as resolved. OutdatedShow resolvedHide resolved

		>>> from functools import partial, Placeholder
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Expand All		@@ -390,16 +391,16 @@ The :mod:`functools` module defines the following functions:
		>>> say_to_world('Hello', 'dear')
		Hello dear world!

		Calling ``say_to_world('Hello')`` wouldresult in :exc:`TypeError`.
		Calling ``say_to_world('Hello')`` wouldraise a :exc:`TypeError`.

		.. versionchanged:: 3.14
		Support for :data:`Placeholder` in args
dg-pb marked this conversation as resolved. OutdatedShow resolvedHide resolved

		.. data:: Placeholder

		This is asingleton objectthat isused as a sentinelfor representing a
		gap in positional arguments when calling :func:`partial`.
		Ithassimilarfeaturesas :data:`None`:
		Asingleton object used as a sentinelto represent a
		"gap" in positional arguments when calling :func:`partial`.
dg-pb marked this conversation as resolved. OutdatedShow resolvedHide resolved
		This objecthas featuressimilar to ``None``:

		>>> type(Placeholder)() is Placeholder
		True
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -281,12 +281,12 @@ class PlaceholderType:
		The type of the Placeholder singleton.
		Used as a placeholder for partial arguments.
		"""
		_singleton = None
		__instance = None
dg-pb marked this conversation as resolved. Show resolvedHide resolved

		def __new__(cls):
		if cls._singleton is None:
		cls._singleton = object.__new__(cls)
		return cls._singleton
		if cls.__instance is None:
		cls.__instance = object.__new__(cls)
		return cls.__instance

		def __repr__(self):
		return 'Placeholder'
Expand All		@@ -313,13 +313,13 @@ class partial:
		def __new__(cls, func, /, args, *keywords):
		if not callable(func):
		raise TypeError("the first argument must be callable")
		placeholder_count = 0
		np = 0
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		nargs = len(args)
		if args:
		while nargs and args[nargs-1] is Placeholder:
		while nargs and args[nargs -1] is Placeholder:
		nargs -= 1
		args = args[:nargs]
		placeholder_count = args.count(Placeholder)
		np = args.count(Placeholder)
dg-pb marked this conversation as resolved. OutdatedShow resolvedHide resolved
		if isinstance(func, partial):
		pargs = func.args
		pnp = func.placeholder_count
Expand All		@@ -335,10 +335,10 @@ def __new__(cls, func, /, args, *keywords):
		pos += 1
		if pnp < nargs:
		all_args.extend(args[pnp:])
		placeholder_count += pnp - end
		np += pnp - end
		args = tuple(all_args)
		else:
		placeholder_count += pnp
		np += pnp
		args = func.args + args
		keywords = {func.keywords, keywords}
		func = func.func
Expand All		@@ -347,26 +347,28 @@ def __new__(cls, func, /, args, *keywords):
		self.func = func
		self.args = args
		self.keywords = keywords
		self.placeholder_count =placeholder_count
		self.placeholder_count =np
		return self

		def __call__(self, /, args, *keywords):
		keywords = {self.keywords, keywords}
		if placeholder_count := self.placeholder_count:
		if len(args) < placeholder_count:
		np = self.placeholder_count
		p_args = self.args
		if np:
		if len(args) < np:
		raise TypeError(
		"missing positional arguments in 'partial' call; expected "
		f"at least {placeholder_count}, got {len(args)}")
		f_args = list(self.args)
		"missing positional arguments "
		"in 'partial' call; expected "
		f"at least {np}, got {len(args)}")
		p_args = list(p_args)
		j, pos = 0, 0
		while j <placeholder_count:
		pos =f_args.index(Placeholder, pos)
		f_args[pos] = args[j]
		while j <np:
		pos =p_args.index(Placeholder, pos)
		p_args[pos] = args[j]
		j += 1
		pos += 1
		return self.func(f_args, args[j:], **keywords)
		else:
		return self.func(self.args, args, **keywords)
		args =args[j:]
		keywords = {self.keywords, keywords}
		return self.func(p_args, args, **keywords)

		@recursive_repr()
		def __repr__(self):
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -1,2 +1,2 @@
		``partial``of``functools`` module now supports placeholders for positional
		arguments.
		Positional argumentsof:func:`functools.partial` objects
		now support placeholders via :data:`functools.Placeholder`.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -26,6 +26,7 @@ typedef struct _functools_state {
		/* this object is used delimit args and keywords in the cache keys */
		PyObject *kwd_mark;
		PyTypeObject *placeholder_type;
		PyObject *placeholder;
		PyTypeObject *partial_type;
		PyTypeObject *keyobject_type;
		PyTypeObject *lru_list_elem_type;
Expand DownExpand Up		@@ -205,7 +206,7 @@ partial_new(PyTypeObject type, PyObject args, PyObject *kw)
		return NULL;
		}

		pto->placeholder =PyObject_CallNoArgs((PyObject *)state->placeholder_type);
		pto->placeholder = state->placeholder;
		Py_ssize_t nnp = 0;
		Py_ssize_t nnargs = PyTuple_GET_SIZE(nargs);
		PyObject *item;
Expand DownExpand Up		@@ -517,7 +518,7 @@ partial_call(partialobject pto, PyObject args, PyObject *kwargs)
		PyObject *pto_args = pto->args;
		PyObject *item;
		Py_ssize_t j = 0; // New args index
		for (Py_ssize_t i=0; i < pto_nargs; i++) {
		for (Py_ssize_t i =0; i < pto_nargs; i++) {
		item = PyTuple_GET_ITEM(pto_args, i);
		if (Py_Is(item, pto->placeholder)) {
		item = PyTuple_GET_ITEM(args, j);
Expand All		@@ -537,10 +538,10 @@ partial_call(partialobject pto, PyObject args, PyObject *kwargs)
		else {
		/* Note: tupleconcat() is optimized for empty tuples */
		args2 = PySequence_Concat(pto->args, args);
		}
		if (args2 == NULL) {
		Py_XDECREF(kwargs2);
		return NULL;
		if (args2 == NULL) {
		Py_XDECREF(kwargs2);
		return NULL;
		}
		}

		PyObject *res = PyObject_Call(pto->fn, args2, kwargs2);
Expand DownExpand Up		@@ -1709,7 +1710,11 @@ _functools_exec(PyObject *module)
		if (PyModule_AddType(module, state->placeholder_type) < 0) {
		return -1;
		}
		if (PyModule_AddObject(module, "Placeholder", PyObject_CallNoArgs((PyObject *)state->placeholder_type)) < 0) {
		state->placeholder = PyObject_CallNoArgs((PyObject *)state->placeholder_type);
		if (state->placeholder == NULL) {
		return -1;
		}
		if (PyModule_AddObject(module, "Placeholder", state->placeholder) < 0) {
		return -1;
		}
		state->partial_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
Expand Down