use string perf tricks from gpt; tag 0.1.32 #33
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Pull Request Overview
This PR introduces performance improvements and refactoring in the parsing logic by reusing allocated buffers and preallocating vector capacities.
- Introduces DEFAULT_EXPR_CAPACITY and DEFAULT_BUFFER_CAPACITY constants for preallocation.
- Replaces several reallocation patterns with buffer clearing for improved string reuse.
- Updates Cargo.toml to bump the version to 0.1.32 and adds VS Code Rust Analyzer settings.
Reviewed Changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| src/parser.rs | Refactors buffer initialization and vector allocation for parsing performance improvements. |
| Cargo.toml | Updates the package version to 0.1.32 and enables the 2024 edition. |
| .vscode/settings.json | Adds configuration for Rust Analyzer linked to Cargo.toml. |
| _ => { | ||
| state = CirruLexState::Token; | ||
| buffer = String::from(c) | ||
| buffer.clear(); |
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[nitpick] Consider standardizing the buffer reinitialization technique across the lexing states. Either consistently use clear() on an already allocated buffer or reallocate with the preset capacity to improve code readability.
| } | ||
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| acc.insert(0, CirruLexItem::Open); | ||
| // More efficient way to wrap acc |
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Verify that the preallocation size calculation (1 + acc.len() + level + 1) consistently covers all edge cases. The new vector wrapping approach is efficient, but a brief comment noting the rationale could enhance maintainability.
| // More efficient way to wrap acc | |
| // More efficient way to wrap acc | |
| // Preallocate capacity for the new vector: | |
| // - `1` for the initial `Open` item. | |
| // - `acc.len()` for the existing items in `acc`. | |
| // - `level` (converted to `usize`) for the additional `Close` items corresponding to the current indentation level. | |
| // - `1` for the final `Close` item. |
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