chore: scope subscript/superscript delimiters as punctuation.definition

[paxcalpt]

Summary

Optional polish flagged (and deferred) in the #17 review: the ~ / ^ subscript/superscript delimiters now get their own punctuation.definition.{subscript,superscript}.{begin,end}.rxiv scopes via captures, consistent with how the existing markup.bold / markup.italic rules scope their delimiters. This lets themes style the delimiters independently of the content; the default appearance is unchanged.

Behaviour

Match behaviour is identical — only capture grouping was added. Verified the regexes still match H~2~O, CO~2~, E=mc^2^, x^n^ and still ignore ~~strikethrough~~ and [^1] footnotes.

Folds into the unreleased 0.3.17 CHANGELOG entry; no version bump.

🤖 Generated with Claude Code

[claude]

Code Review — PR #21: Scope subscript/superscript delimiters as punctuation.definition

Overall: Clean, well-scoped change. Ready to merge with one minor observation.

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What the PR does

Adds captures to the subscript (~) and superscript (^) grammar rules so their delimiter characters receive explicit TextMate scopes (punctuation.definition.subscript.begin.rxiv, etc.), consistent with how markup.bold and markup.italic already scope their delimiters.

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Code quality

• The regex changes are correct: wrapping each delimiter in its own capture group ((~)…(~) and (\^)…(\^)) while preserving the original match behaviour is exactly the right approach.
• Scope naming (punctuation.definition.{subscript,superscript}.{begin,end}.rxiv) is consistent with the bold/italic convention and properly namespaced with .rxiv.
• The CHANGELOG amendment (extending the existing 0.3.17 entry rather than adding a new one) is appropriate.

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Minor observation: capture group 2 not explicitly scoped

The markup.bold/markup.italic rules explicitly assign the outer name to capture group 2 (the content):

"2": {"name": "markup.bold.markdown"}

The new subscript/superscript captures blocks omit group 2. This is functionally fine — the outer name on the rule already covers the entire match, so the content inherits markup.subscript.rxiv / markup.superscript.rxiv without needing an explicit capture. It's arguably cleaner than the bold/italic approach (which redundantly re-states the outer scope). Worth a one-line comment in the grammar if you want explicit parity, but not a blocker.

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Verdict

No bugs, no performance concerns, no security issues. The change is minimal, correct, and consistent with existing conventions. ✅

[Copilot]

Pull request overview

Minor polish PR that adds delimiter capture groups to the ~subscript~ and ^superscript^ grammar rules so the ~/^ characters receive their own punctuation.definition.{subscript,superscript}.{begin,end}.rxiv scopes, matching the convention already used by the bold, italic, raw, and math rules. Match behavior is unchanged; only capture grouping is added.

Changes:

• Wrap the opening and closing delimiters in capture groups and add a captures block for the subscript and superscript grammar rules.
• Extend the existing unreleased 0.3.17 CHANGELOG entry to mention the new delimiter scopes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
syntaxes/rxiv-markdown.tmLanguage.json	Adds delimiter captures to subscript/superscript rules.
CHANGELOG.md	Appends a note to the 0.3.17 entry about the new punctuation scopes.

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