3618e6fd2c
Add span_to_markdown function that translates span flags to Markdown: - Bold (bit 0) → **text** - Italic (bit 1) → *text* - Bold+italic → ***text*** - Subscript (bit 3) → <sub>text</sub> - Superscript (bit 4) → <sup>text</sup> - Smallcaps (bit 2) → <span style="font-variant: small-caps">text</span> - Color-only differences: no styling - Escapes CommonMark special characters Tests cover all acceptance criteria: - Bold+italic combination - Subscript/superscript emission - Smallcaps HTML span - Special character escaping - Whitespace-only edge cases Closes: pdftract-56yz8
66 lines
2.9 KiB
Markdown
66 lines
2.9 KiB
Markdown
# Bead pdftract-56yz8: Inline Span Styling (Phase 6.5)
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## Summary
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Implemented `span_to_markdown` function that translates span flag bitmask values to Markdown inline syntax per Phase 6.5 of the plan (lines 2188-2195).
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## Changes Made
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### File: `crates/pdftract-core/src/markdown.rs`
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1. Added `SpanJson` import to the module
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2. Implemented `span_to_markdown(span: &SpanJson) -> String`:
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- Reads span flags vector (`Vec<String>`) for style indicators
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- Emits appropriate Markdown syntax based on flags
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- Handles combinations: bold+italic → `***text***`
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- Handles script nesting: `**<sub>text</sub>**` (scripts inside bold/italic)
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- Handles smallcaps+script: `**<span><sup>text</sup></span>**` (scripts inside smallcaps)
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- Skips whitespace-only spans (no point styling whitespace)
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- Color-only differences: no styling emitted
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3. Implemented `escape_markdown_inline(s: &str) -> String`:
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- Escapes CommonMark special characters: `\` `` ` `` `*` `_` `[` `]` `(` `)` `#` `!` `+` `<` `>`
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- Does NOT escape `-` `.` `=` (not special in inline context per CommonMark)
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4. Added comprehensive test coverage (20+ tests):
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- Bold, italic, bold+italic combinations
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- Subscript, superscript, smallcaps individually
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- Combined styling (bold+subscript, italic+superscript, all flags)
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- Special character escaping
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- Whitespace-only edge cases
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### File: `crates/pdftract-core/src/lib.rs`
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- Exported `span_to_markdown` from the markdown module for public API
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## Acceptance Criteria Status
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| Criterion | Test | Status |
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|-----------|------|--------|
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| Bold + italic → ***text*** | `test_span_to_markdown_bold_italic` | PASS |
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| Subscript → `<sub>2</sub>` | `test_span_to_markdown_subscript` | PASS |
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| Superscript → `<sup>th</sup>` | `test_span_to_markdown_superscript` | PASS |
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| Smallcaps → `<span style="font-variant: small-caps">CAPS</span>` | `test_span_to_markdown_smallcaps` | PASS |
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| Color-only difference: no styling | `test_span_to_markdown_no_flags` | PASS |
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| Special chars escaped: "1*2" → "1\*2" | `test_span_to_markdown_special_chars_escaped` | PASS |
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## Test Results
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```
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cargo test --package pdftract-core --lib markdown
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test result: ok. 43 passed; 0 failed
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```
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All acceptance criteria tests pass.
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## Implementation Notes
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1. **Nesting order**: Following plan guidance "emit **<sub>text</sub>** not <sub>**text**</sub>", script tags are placed inside bold/italic wrappers. For smallcaps+script combinations, smallcaps wraps scripts (e.g., `<span><sup>text</sup></span>`).
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2. **Escaping**: Implemented per CommonMark spec - only escapes characters that have special meaning in inline Markdown context. Characters like `-` and `.` are NOT escaped because they're only special at line start (for lists/HR), not inline.
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3. **Edge cases**: Whitespace-only spans skip styling entirely to avoid emitting empty formatting like `** **`.
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## Commits
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- `pdftract-core`: Add span_to_markdown function with inline span styling (Phase 6.5)
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