Spec: Version and platform checking underspecified

Currently, the "Version and platform checking" section of the typing spec is very barebones. It basically says:

Type checkers are expected to understand simple version and platform checks. [...] Don’t expect a checker to understand obfuscations like "".join(reversed(sys.platform)) == "xunil".

Of course, there's a world of difference between these two forms.

The type stubs document goes into a bit more of detail, and reflects the currently implemented functionality quite well, as far as I know. It would be a good starting point.

Maybe it would also make sense to support platform checks using startswith(), as that is officially recommended in the Python docs, and is required to properly support some Unix variants, like FreeBSD, that include the version number in the platform string. See also python/typeshed#11876.

Comienza comparando la sección “Version and platform checking” de la especificación de typing con el documento de stubs de tipos enlazado, que refleja el comportamiento actual. Revisa la documentación de Python y el issue de typeshed enlazados en el informe; después, define las comprobaciones admitidas y decide si startswith() pertenece a la especificación. Se considera terminado cuando la especificación describe con precisión el comportamiento previsto de comprobación de versiones y plataformas.