Show trailing commas in more places [SE-0439] #421
+58
−16
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The grammar as written overproduces by allowing a comma after any element in the literal -- while this does produce an optional trailing comma, it also produces an optional second comma after any list element. By definition, a trailing comma comes after only the last element.
The grammar for \() interpolation in string literals doesn't produce any commas. Updating that can be part of the docs work for SE-0228 and SE-0477 -- there's nowhere to add a trailing comma right now.
This issue was resolved in commit 37eb636 (Show multiline string with indentation in the tour (swiftlang#121), 2023-03-30). References: 37eb636
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This updates the formal grammar and reference for all new places where a trailing comma is allowed, and shows them in the guide's discussion of array and dictionary literals. The guided tour already shows an example, so no change there except removing a stale TODO comment.
The SE proposal also adds support for trailing commas in
\()style string interpolation, but the documentation for string interpolation currently only talks about the older single-expression form, so there isn't a place to add trailing commas. When updating the docs for SE-0228, adding info about trailing commas can be part of that work. See interpolation_grammar_73014172 for some initial work there.Fixes: #418
Fixes: rdar://144570685