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@stestagg
Last active August 7, 2020 16:23
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POC exploring possible syntaxes for the python-ideas thread: Package kwkey and PEP 472 -- Support for indexing with keyword arguments
# coding=kw_getitem
class Helper:
def _getitem_wrapper(self, *a, **kw):
a_x = {0: (), 1: a}.get(len(a), (a, ))
return self.__getitem__(*a_x, **kw)
class ObjWithGetitem(Helper):
def __getitem__(self, key=None, foo=None, bar=None):
print(f'{key=} {foo=}')
def main():
obj = ObjWithGetitem()
obj[1]
# key=1 foo=None
obj[foo=1]
# key=None foo=1
obj[1, foo=2]
# key=1 foo=2
obj[1, 2]
# key=(1, 2) foo=None
obj[1, 2, foo=3]
# key=(1, 2) foo=3
obj[(1, 2), foo=3]
# key=(1, 2) foo=3
obj[(1, 2), 3, foo=4]
# key=((1, 2), 3) foo=4
obj[**{'foo': 9}]
# key=None foo=9
obj[1, 2, foo=3, xxx=5]
# TypeError: __getitem__() got an unexpected keyword argument 'xxx'
from codecs import register, CodecInfo
import re
def wrap_subs(match):
return f'._getitem_wrapper({match.group(1)})'
def decode(x):
source = bytes(x).decode('utf8')
decoded = re.sub(r'\[(.*?)\]', wrap_subs, source)
return decoded, len(source)
register(lambda n: CodecInfo(None, decode) if n == 'kw_getitem' else None)
import example
example.main()
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