On Sat, Oct 27, 2018 at 5:53 PM alanfo <alan.f...@gmail.com> wrote: > > As a general principle, Ian, that makes sense to me and perhaps it's > something we could all unite on. > > The remaining problem is how to distinguish between the two cases - new > keywords used as such or as ordinary identifiers. > > Your suggestion is to leave it to the compiler to figure that out from usage > whereas rog favors stating up front which version of the language is being > parsed. > > Personally, I think I prefer rog's approach as it would then be immediately > clear to both the compiler and the human reader what was intended. > > As it's a package (rather than a file) level aspect, I propose adding an > optional tag to the package clause. > > If there were no tag, then the compiler would only recognize version 1 > keywords and newer ones would be treated as ordinary identifiers.
What if the package name becomes a keyword? package contract In my opinion, backward compatibility problems because of new keywords are among the easiest to solve. It only requires a consistent renaming of a symbol, which can be done by running grep/sed. > > If there were a tag such as: > > package whatever "go 2" > > then all keywords introduced up to version 2 would be recognized as such and > their use as ordinary identifiers outlawed. > > Assuming new keywords would only appear in new major versions of the > language, we could then carry on with tags of "go 3", "go 4" etc. > > Alan > > On Saturday, October 27, 2018 at 10:10:55 PM UTC+1, Ian Lance Taylor wrote: >> >> On Sat, Oct 27, 2018 at 3:31 AM, <alan...@gmail.com> wrote: >> > >> > Both the above are also 'take it or leave it' approaches. Either you can >> > use >> > the new keywords as such or you can use them as ordinary identifiers - you >> > can't do both in the same package which my suggestion would allow. >> >> That is an interesting feature but I don't think it's a necessary one. >> It's important that we be able to continue to compile existing code >> that uses identifiers that are now keywords. But it's not important >> that we permit that code to start using the keyword without renaming >> the identifier. Keywords always start with a lowercase letter, and so >> the corresponding identifiers are never exported. It's always >> possible to stop using an unexported identifier without breaking any >> other packages. So if you want to start using a keyword, stop using >> the identifier, by renaming the existing uses. That seems like a >> clear and reasonable requirement for moving forward to a new language >> version. We can even provide a `go fix` hook for it. >> >> Ian > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
