Allowing identifier to begin with digit

[davedelong]

True... but that rejection also specifically leaves the question of numeric-starting identifiers open for further discussion:

@Joe_Groff

• This feature could also be used to enable libraries to more directly encode domain-specific names that are not currently valid Swift identifiers, such as status codes which begin with numbers like HTTPStatus.404 , naming conventions that use normally-reserved symbols like SFSymbols.10.circle , or names from other languages Swift may interoperate with that have different valid identifier character sets like Forth.FM/MOD . This use case is more in line with the original intent of the backtick identifier feature, which was to allow for interop with libraries from C/ObjC/C++ that use names that would normally be reserved in Swift. However, the core team would like to see more concrete work done on libraries that would benefit from this functionality, to better gauge whether it is really essential or merely nice-to-have, and whether allowing a more restricted character set could achieve the desired results with less tooling complexity burden.

(emphasis added) To me, it seems like this proposal would fall under the "more concrete work" banner.