Unwrap parenthesized expressions in unified Swift extraction

[Copilot]

Parenthesized Swift conditions such as while (x > 0) were extracted as opaque tuple expressions, omitting the contained comparison.

• Tuple expression mapping
  • Elide unlabelled single-element tupleExpr nodes as grouping expressions.
  • Retain tuple extraction for other tuple forms.

while (x > 0) { ... }

now extracts the condition as the x > 0 binary expression.

[aschackmull]

Quick question on the recursive translation and semantics of sequential rule-macro evaluation: As far as I've understood, the single-@ on label and rest mean "do recursive translation". Is this work wasted if the where clause fails and we proceed to the next tupleExpr rule below (which also specifies recursive translation), or is the recursive translation guaranteed to only be done once? To put it differently, would this pair of rules be more efficient if they used @@ for label and rest?

[tausbn]

For the purposes of the guard, all @-captures behave as if they are @@-captures. That is, guard evaluation happens before any automatic translation takes place.

(This makes the syntax a bit awkward, but the alternative would be to force the user to explicitly translate things that could have been auto-translated, and this seemed like the worse option to me.)

[Copilot]

🟡 Changes recommended

The unwrapping guard incorrectly matches trailing-comma tuples such as (x,).

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR updates Swift extraction to unwrap parenthesized grouping expressions while preserving tuple structure.

Changes:

• Adds single-element tuple-expression unwrapping.
• Preserves multi-element tuple mappings.
• Updates Swift extraction corpus expectations.

File summaries

File	Description
unified/extractor/tests/corpus/swift/operators/parenthesised-expression.output	Updates grouped expression extraction.
unified/extractor/tests/corpus/swift/control-flow/switch-expression-pattern.output	Verifies structured tuple patterns.
unified/extractor/tests/corpus/swift/collections/tuple-literal.output	Verifies tuple literal extraction.
unified/extractor/src/languages/swift/swift.rs	Implements tuple-expression mapping and unwrapping.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 1
• Review effort level: Lite

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[tausbn]

Looks good to me! 👍
(Edit: Spoke too soon -- Copilot raised a valid issue.)