Skip to content

bpo-32492: C Fast path for namedtuple's property/itemgetter pair #5100

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
rhettinger wants to merge 4 commits into from
Closed

bpo-32492: C Fast path for namedtuple's property/itemgetter pair #5100

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
002ee27
Working pure python version
rhettinger Dec 30, 2017
9f3da00
Add slots and a property-based __doc__ (deletion is a bit different)
rhettinger Dec 30, 2017
eab8d3a
Inherit from property()
rhettinger Dec 30, 2017
85dc70b
Prepare for C version
rhettinger Dec 30, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 7 additions & 9 deletions Lib/collections/__init__.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -301,7 +301,10 @@ def __eq__(self, other):
### namedtuple
################################################################################

_nt_itemgetters = {}
try:
from _collections import _tuplegetter
except ImportError:
_tuplegetter = lambda index: property(_itemgetter(index))

def namedtuple(typename, field_names, *, rename=False, module=None):
"""Returns a new subclass of tuple with named fields.
Expand Down Expand Up @@ -427,15 +430,10 @@ def __getnewargs__(self):
'_asdict': _asdict,
'__getnewargs__': __getnewargs__,
}
cache = _nt_itemgetters
for index, name in enumerate(field_names):
try:
itemgetter_object, doc = cache[index]
except KeyError:
itemgetter_object = _itemgetter(index)
doc = f'Alias for field number {index}'
cache[index] = itemgetter_object, doc
class_namespace[name] = property(itemgetter_object, doc=doc)
tuplegetter = _tuplegetter(index)
tuplegetter.__doc__ = f'Alias for field number {index}'
class_namespace[name] = tuplegetter

result = type(typename, (tuple,), class_namespace)

Expand Down
22 changes: 22 additions & 0 deletions Modules/_collectionsmodule.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2354,6 +2354,28 @@ _count_elements(PyObject *self, PyObject *args)
Py_RETURN_NONE;
}

/* _tuplegetter *********************************************************/

/*

class _tuplegetter(property):
'Emulate property(itemgetter(index)) with writeable __doc__'

def __init__(self, index):
self.index = index

def __get__(self, obj, objtype=None):
if obj is None:
return self
return obj[self.index]

typedef struct {
PyPropertyObject po;
Py_ssize_t index;
} _tuplegetterobject;

*/

/* module level code ********************************************************/

PyDoc_STRVAR(module_doc,
Expand Down