Find which section a node belongs to

Goal: You already have a single node (say, the first code block in a doc) and want to know which heading section it lives under, e.g. to report “found this in the Installation section”.

Prerequisites: The section module, via -A or nodes.

Query

$ mq -A 'let n = first(compact(.code)) | section::containing(n) | section::title' README.md

Or with nodes:

import "section"
| nodes
| let n = first(compact(.code))
| section::containing(n) | section::title

Input

# Introduction

Welcome.

## Installation

```bash
npm install
```

## Usage

Run it.

Output

Installation

Notes

• section::containing(md_nodes, node) is the reverse of picking a section apart: given all the document’s nodes and one node you already have, it returns the section::sections-style dict that node belongs to (or None if it doesn’t belong to any).
• It matches the given node against each section’s header and children by equality, so it works with any node you found some other way — a plain selector match (.code, .h2, …), a filter/is_* predicate, or an item you pulled out of section::body.
• Matching is structural: a document with duplicate content (e.g. two identical code blocks) resolves to the first section that contains a matching node.
• Pass true as the third argument to match against depth-extended sections (see section::sections’s depth parameter) instead of the immediate section.