On 4 September 2016 at 19:29, Nick Coghlan <ncogh...@gmail.com> wrote:
> So in this case, attempting to entirely defer specification of the > semantics creates a significant risk of type checkers written on the > assumption of C++ or Java style type declarations actively inhibiting > the dynamism of Python code, suggesting that the PEP would be well > advised to declare not only that the PEP 484 semantics are unchanged, > but also that a typechecker that flags the example above as unsafe is > wrong to do so. > I don't think that a dedicated syntax will increase the risk more than the existing type comment syntax. Moreover, mainstream type checkers (mypy, pytype, etc) are far from C++ or Java, and as far as I know they are not going to change semantics. As I understand, the main point of Mark is that such syntax suggests visually a variable annotation, more than a value annotation. However, I think that the current behavior of type checkers will have more influence on perception of people rather than a visual appearance of annotation. Anyway, I think it is worth adding an explicit statement to the PEP that both interpretations are possible (maybe even add that value semantics is inherent to Python). But I don't think that we should *prohibit* something in the PEP. -- Ivan
_______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
