pdftract/notes/pdftract-37wcw.md

pdftract-37wcw: Table emission verification

Bead: 6.5.4 Table emission (GFM pipe + HTML fallback for merged cells) + caption italic

Implementation Summary

The table emission functionality was already implemented in /home/coding/pdftract/crates/pdftract-core/src/markdown.rs:

1. emit_table (line 1042-1055): Main function that decides between GFM and HTML
2. emit_gfm_table (line 1064-1140): Emits GFM pipe tables for simple tables
3. emit_html_table (line 1147-1185): Emits HTML tables for complex tables
4. escape_pipe (line 1194-1219): Escapes pipes and handles newlines

Acceptance Criteria Status

Criterion	Status	Evidence
Critical test: merged-cell table -> HTML fallback	✅ PASS	test_emit_table_merged_cells_html_fallback passes
Simple 3x3 table: GFM pipe format	✅ PASS	test_emit_table_simple_3x3 passes
Caption appears as italic line below table	✅ PASS	Handled in block_to_markdown (line 270-272): *{text}*\n
Cell with pipe character: escaped as |	✅ PASS	test_escape_pipe and test_emit_table_with_pipe_in_cell pass
Cell with newline: rendered with <br>	✅ PASS	test_escape_pipe_newline_to_br and test_emit_table_with_newline_in_cell pass
Nested-block cell: HTML fallback	⚠️ N/A	Schema doesn't support nested blocks in cells (only text + spans)

Test Results

$ cargo test -p pdftract-core --lib 'markdown::'
running 65 tests
test result: ok. 65 passed; 0 failed; 0 ignored

All table emission tests pass:

• test_emit_table_empty - Empty table returns empty string
• test_emit_table_merged_cells_html_fallback - Merged cells trigger HTML fallback
• test_emit_table_rowspan_html_fallback - Rowspan triggers HTML fallback
• test_emit_table_no_header - Tables without header row use first row as header
• test_emit_table_simple_3x3 - Simple table uses GFM pipe format
• test_emit_table_with_newline_in_cell - Newlines become <br> tags
• test_emit_table_single_row - Single row tables work correctly
• test_emit_table_with_pipe_in_cell - Pipes escaped as \|

Implementation Details

Simple table detection (GFM):

let is_simple = table.rows.iter().all(|row| {
    row.cells.iter().all(|cell| cell.rowspan == 1 && cell.colspan == 1)
});

GFM pipe table format:

| Header 1 | Header 2 | Header 3 |
| --- | --- | --- |
| Data 1 | Data 2 | Data 3 |

HTML fallback for merged cells:

<table>
  <tr>
    <th colspan="2">Merged Header</th>
    <th>Header 2</th>
  </tr>
  ...
</table>

Caption handling: Captions are separate blocks (kind: "caption") emitted as italic text:

*Table caption*

Notes

1. Nested blocks in cells: The current CellJson schema only has text (String) and spans (Vec). There's no support for nested block elements like paragraphs within cells. This appears to be a forward-looking requirement or something that doesn't exist in the current data model.

2. Header-less tables: GFM requires a header row. The implementation synthesizes an empty header row for tables with is_header=false on all rows (the first row becomes the header).

3. Column padding: The implementation correctly handles variable-width rows by padding with empty cells to match the maximum column count.

Files Modified

No files were modified - the implementation was already complete. All tests pass.

Commits

N/A - No changes made, implementation already exists.