New submission from STINNER Victor <vstinner@redhat.com>: The Python 3 language has a strict definition for an identifier: https://docs.python.org/dev/reference/lexical_analysis.html#identifiers ... but in practice, it's possible to create "invalid" identifiers using setattr(). Example with PyPy: $ pypy Python 2.7.13 (0e7ea4fe15e82d5124e805e2e4a37cae1a402d4b, Apr 12 2018, 14:50:12)
class A: pass
a=A() setattr(a, "1", 2) getattr(a, "1") 2
vars(a) {'1': 2} a.__dict__ {'1': 2}
a.1 File "<stdin>", line 1 a.1 ^ SyntaxError: invalid syntax
The exact definition of "identifiers" is a common question. Recent examples: * bpo-25205 * [Python-Dev] Arbitrary non-identifier string keys when using **kwargs https://mail.python.org/pipermail/python-dev/2018-October/155435.html It would be nice to document the answer. Maybe in the Langage Specification, maybe in the setattr() documentation, maybe in a FAQ, maybe everywhere? ---------- assignee: docs@python components: Documentation messages: 328816 nosy: docs@python, serhiy.storchaka, steven.daprano, vstinner priority: normal severity: normal status: open title: Document that CPython accepts "invalid" identifiers versions: Python 3.8 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue35105> _______________________________________