It would be useful to first estimate how many projects would be broken by such incompatible change (stricter syntax).
Inada-san wrote https://github.com/methane/notes/blob/master/2020/wchar-cache/download_sdist.py to download source files using https://hugovk.github.io/top-pypi-packages/ API (top 4000 PyPI projects). Victor On Tue, Apr 13, 2021 at 10:59 PM Guido van Rossum <gu...@python.org> wrote: > > On Tue, Apr 13, 2021 at 12:55 PM Serhiy Storchaka <storch...@gmail.com> wrote: >> >> 26.04.18 21:37, Serhiy Storchaka пише: >> > In Python 2.5 `0or[]` was accepted by the Python parser. It became an >> > error in 2.6 because "0o" became recognizing as an incomplete octal >> > number. `1or[]` still is accepted. >> > >> > On other hand, `1if 2else 3` is accepted despites the fact that "2e" can >> > be recognized as an incomplete floating point number. In this case the >> > tokenizer pushes "e" back and returns "2". >> > >> > Shouldn't it do the same with "0o"? It is possible to make `0or[]` be >> > parseable again. Python implementation is able to tokenize this example: >> > >> > $ echo '0or[]' | ./python -m tokenize >> > 1,0-1,1: NUMBER '0' >> > 1,1-1,3: NAME 'or' >> > 1,3-1,4: OP '[' >> > 1,4-1,5: OP ']' >> > 1,5-1,6: NEWLINE '\n' >> > 2,0-2,0: ENDMARKER '' >> > >> > On other hand, all these examples look weird. There is an assymmetry: >> > `1or 2` is a valid syntax, but `1 or2` is not. It is hard to recognize >> > visually the boundary between a number and the following identifier or >> > keyword, especially if numbers can contain letters ("b", "e", "j", "o", >> > "x") and underscores, and identifiers can contain digits. On both sides >> > of the boundary can be letters, digits, and underscores. >> > >> > I propose to change the Python syntax by adding a requirement that there >> > should be a whitespace or delimiter between a numeric literal and the >> > following keyword. >> > >> >> New example was found recently (see https://bugs.python.org/issue43833). >> >> >>> [0x1for x in (1,2)] >> [31] >> >> It is parsed as [0x1f or x in (1,2)] instead of [0x1 for x in (1,2)]. >> >> Since this code is clearly ambiguous, it makes more sense to emit a >> SyntaxWarning if there is no space between number and identifier. > > > I would totally make that a SyntaxError, and backwards compatibility be > damned. > > -- > --Guido van Rossum (python.org/~guido) > Pronouns: he/him (why is my pronoun here?) > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/OU3USHVMXZJD4SA3FJGQQVQYAORHY5BM/ > Code of Conduct: http://python.org/psf/codeofconduct/ -- Night gathers, and now my watch begins. It shall not end until my death. _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/5VYOQRW4DOVDNSIB3G7GBHSUL5ZC3QZO/ Code of Conduct: http://python.org/psf/codeofconduct/
