impl more ast by youknowone · Pull Request #6419 · RustPython/RustPython

Walkthrough

This PR refactors AST pattern handling in the Rust VM stdlib, replacing placeholder implementations with concrete vector-based structs. Three PatternMatchClass related structures now wrap vectors instead of ranges. Functions for splitting and merging pattern arguments are updated to handle actual data conversions for Singleton values and pattern components.

Changes

Cohort / File(s)

Summary

Pattern AST Refactoring crates/vm/src/stdlib/ast/pattern.rs

Refactored PatternMatchClassPatterns, PatternMatchClassKeywordAttributes, and PatternMatchClassKeywordPatterns from placeholder range-based structs to vector-based newtype wrappers. Implemented trait methods (ast_to_object, ast_from_object) for ruff::Singleton to convert between Python objects (None, True, False) and Rust enum variants. Updated split_pattern_match_class and merge_pattern_match_class to construct and deconstruct public vector-based components with proper keyword pattern handling.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

• Struct representation changes: Verify that the newtype wrapper conversions correctly delegate to inner vectors and handle edge cases.
• Singleton implementation: Ensure ast_to_object and ast_from_object properly map between Python objects and enum variants, and that error handling is complete.
• split/merge function logic: Carefully review the merge_pattern_match_class construction of PatternKeyword items with proper range and node_index defaults to ensure correct round-tripping of AST data.

Poem

🐰 From ranges sparse to vectors full of might,
We pack our patterns tight, a refactor's delight.
Singletons sing true—None, False, and True—
Now serialized and round-tripped, the old TODOs are through! ✨

Pre-merge checks and finishing touches

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 9.09% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.
Title check	❓ Inconclusive	The title 'impl more ast' is vague and generic, using non-descriptive terms that don't convey meaningful information about the specific changes made.	Consider using a more descriptive title that reflects the specific implementation, such as 'Implement proper serialization for Singleton and vector-based PatternMatchClass structures' or similar.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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