[Pitch] Formalize ‘Swift language mode’ naming in tools and API

[James_Dempsey]

@jrose

The equivalent in the Rust world is “edition”, a term that I believe the Rust folks made up without particular precedent (though I didn’t research that deeply). I think “language mode” is fine, and an improvement over “version” (or “standard”, which got stretched with things like “gnu99”), but “edition” could probably be listed as a Considered Alternative.

Thank you for the feedback and I will definitely add "edition" to the considered alternatives. It is interesting that it seems Rust created a term without precedent. I think Swift has done the same with “language mode”.

Searching here in the forums, it does seem like "language mode" is a long-established term of art in the Swift community:
https://forums.swift.org/search?q=%22language%20mode%20%22
(A space added to end of search term to avoid finding 'language model')

This includes the posts in the last year from LSG members about Swift 6 language mode:

• Design Priorities for the Swift 6 Language Mode
• Progress toward the Swift 6 language mode

The earliest usage of the term I could find goes back to 2016 in a post describing the intent to allow for modules to use different versions of Swift:

@tkremenek

For language syntax/semantics, the compiler can use the language mode to properly implement the language version being used by a module.

From: End of source-breaking changes for Swift 3.

Overall, I am open to whatever name adds clarity and removes the ambiguity, but "language mode" appears to be the term that has been consistently used for a long while.