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overlookmotel
a1478783f0
Remove mention of `Atom` from `oxc_span` crate's README. `Atom` has been moved to `oxc_str` crate.
43 lines
1.5 KiB
Markdown
43 lines
1.5 KiB
Markdown
# Oxc Span
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Source position utilities and span management for precise error reporting.
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## Overview
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This crate provides essential utilities for managing source positions and spans in JavaScript and TypeScript code. It enables precise error reporting, source mapping, and location-aware transformations across all oxc tools.
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## Key Features
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- **Precise positions**: Accurate byte-level source positions
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- **Span utilities**: Source ranges with start and end positions
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- **Source type detection**: Automatic language and module detection
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- **Content comparison**: Semantic equality for AST nodes
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## Architecture
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### Span System
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- **Byte positions**: All positions are UTF-8 byte offsets
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- **Inclusive ranges**: Spans include start position, exclude end position
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- **Efficiency**: Uses u32 for positions, supporting files up to 4GB
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- **Precision**: Enables precise error highlighting and source maps
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### Source Type System
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The source type encodes important metadata:
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- **Language**: JavaScript vs TypeScript
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- **Module system**: ESM vs Script
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- **JSX support**: JSX vs plain syntax
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- **Variant**: Standard vs definition files (.d.ts)
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### Integration Points
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- **Parser**: Creates spans during tokenization and parsing
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- **Semantic**: Tracks spans for all symbols and references
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- **Linter**: Uses spans for precise error reporting
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- **Codegen**: Maintains spans for source map generation
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- **Transformer**: Preserves spans during AST manipulation
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This crate provides the foundation for precise source location tracking throughout the oxc toolchain.
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