MDEx Multiline Cells

An MDEx plugin enabling multi-line cells in Markdown tables with full inline/block Markdown rendering and automatic key-column continuation guessing.

Overview

Standard GFM (GitHub Flavored Markdown) pipe tables restrict each table row to a single physical line. MDEx Multiline Cells extends MDEx by adding support for multi-line table rows while preserving rich Markdown syntax (bold, italic, code blocks, links, math, and inline elements).

Key Features

Automatic Continuation Guessing: Automatically infers multi-line cell continuations when a table row's primary key column (e.g., 1st column) is empty.
Multiple Multi-line Syntaxes:
- Trailing backslash \ at line ends inside table rows.
- Double backslash \\ in cell text.
- Unclosed multi-line table cell continuation across physical lines.
- Explicit  ,  , or   HTML line break tags in cell contents.
Rich Markdown Formatting: Preserves bold (**), italics (*), inline code (`), links ([text](url)), images, and AST nodes across cell line segments.
Protected Code Fences: Ignores table-like pipe syntax inside fenced code blocks (``` and ~~~).
Configurable Output Modes:
- :line_break (default) - Renders line breaks inside table cells as   (MDEx.LineBreak) preserving inline formatting.
- :paragraph - Wraps each line segment within table cells in  paragraph blocks.
- :html_br - Renders line breaks as raw   HTML inline nodes.

Installation

Add mdex_multiline_cells to your list of dependencies in mix.exs:

def deps do
  [
    {:mdex_multiline_cells, "~> 0.1"},
    {:mdex, "~> 0.13"}
  ]
end

Usage

1. Automatic Continuation via Empty Key Column

markdown = """
| #  | Issue | Location | Suggested Fix |
|----|-----------------------------------|--------------------------|-----------------------------------------------------|
| B1 | Synchronous DB writes in hot path | orchestrator.ex:890, 425 | Wrap StepMetrics.record_metric in Task.start        |
|    |                                   |                          | or use a GenServer/Agent collector that batches     |
|    |                                   |                          | writes. At minimum, use Task.Supervisor.start_child |  
|    |                                   |                          | with a dedicated supervisor.                        |
| B2 | toggle_debug_panel latch bug —    | blah.ex:100              | Change to assign(:debug_log_enabled?, new_panel) or |
|    | debug_log_enabled? never resets   |                          | introduce a separate debug_panel_ever_opened? flag. |
|    | to false after first open         |                          |                                                     |
"""

html = MDEx.to_html!(markdown, plugins: [MdexMultilineCells])

2. Explicit Line Continuation (`\`) & ` ` Tags

markdown = """
| Feature | Details | Status |
| :--- | :--- | :---: |
| **Multi-line Cells** | Line 1 of description \\
Line 2 of description with `code` | Active |
| **Rich Formatting** | **Bold Line 1**<br>[Elixir Docs](https://elixir-lang.org) | Done |
"""

html = MDEx.to_html!(markdown, plugins: [MdexMultilineCells])

3. Via `MDEx.new/1`

Attach the plugin when initializing an MDEx.Document:

MDEx.new(markdown: markdown, plugins: [MdexMultilineCells])
|> MDEx.to_html!()

4. Direct Attachment

MDEx.new(markdown: markdown)
|> MdexMultilineCells.attach(render_as: :paragraph)
|> MDEx.to_html!()

Configuration & Plugin Options

Options can be passed as a keyword list when attaching the plugin:

MDEx.to_html!(markdown, plugins: [{MdexMultilineCells, render_as: :paragraph, guess_multiline: true}])

Option	Type	Default	Description
`:guess_multiline`	`boolean()`	`true`	Infers multi-line cell continuations when a row's key column is empty.
`:key_column`	`non_neg_integer()`	`0`	0-indexed position of the key column used for multi-line continuation guessing.
`:render_as`	`:line_break` \| `:paragraph` \| `:html_br`	`:line_break`	Controls how multi-line cell line segments render in HTML/AST output.
`:continuation_syntax`	`:all` \| `:backslash` \| `:unclosed`	`:all`	Specifies which multi-line syntax to process in table source.
`:strip_indentation`	`boolean()`	`true`	Whether to strip leading indentation on continuation lines.

Generated HTML Output Examples

Default (`render_as: :line_break`)

<table>
<thead>
<tr>
<th>#</th>
<th>Issue</th>
<th>Location</th>
<th>Suggested Fix</th>
</tr>
</thead>
<tbody>
<tr>
<td>B1</td>
<td>Synchronous DB writes in hot path</td>
<td>orchestrator.ex:890, 425</td>
<td>Wrap StepMetrics.record_metric in Task.start<br />
or use a GenServer/Agent collector that batches<br />
writes. At minimum, use Task.Supervisor.start_child<br />
with a dedicated supervisor.</td>
</tr>
</tbody>
</table>

Paragraph Mode (`render_as: :paragraph`)

<table>
<thead>
<tr>
<th><p>Item</p></th>
<th><p>Description</p></th>
</tr>
</thead>
<tbody>
<tr>
<td><p>Task 1</p></td>
<td>
<p>Line 1 of description</p>
<p>Line 2 of description</p>
</td>
</tr>
</tbody>
</table>

License

This project is licensed under the MIT License.