This moves a document's abstract from the main text into the metadata. Metadata elements usually allow for finer placement control in the final output, but writing body text is easier and more natural.

A document abstract can either be put directly in the document metadata, for example by inserting an abstract attribute into a YAML block.

---
abstract: |
  Place abstract here.

  Multiple paragraphs are possible.
---

The additional indentation and formatting requirements in YAML headers can be confusing or annoying for authors. It is hence preferable to allow abstracts be written as normal sections.

# Abstract

Place abstract here.

Multiple paragraphs are possible.

This filter turns the latter into the former by looking for a top-level header whose ID is abstract. Pandoc auto-creates IDs based on header contents, so a header titled Abstract will satisfy this condition.^[1]

[1]: This requires the auto_identifier extension. It is enabled by default.