https://github.com/savetheclocktower/tree-sitter-frontmatter

A parser for front matter blocks (typically found in Markdown files)
https://github.com/savetheclocktower/tree-sitter-frontmatter

Last synced: about 1 month ago
JSON representation

A parser for front matter blocks (typically found in Markdown files)

• Host: GitHub
• URL: https://github.com/savetheclocktower/tree-sitter-frontmatter
• Owner: savetheclocktower
• Created: 2023-07-13T22:45:52.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-11-11T19:55:06.000Z (about 1 year ago)
• Last Synced: 2023-11-11T20:33:08.984Z (about 1 year ago)
• Language: C
• Homepage:
• Size: 8.79 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# tree-sitter-frontmatter

[Tree-sitter][] parser for [front matter](https://jekyllrb.com/docs/front-matter/) in arbitrary files.

Does not try to understand the contents of the file beyond the front matter delimiters. The proper parsers for the front-matter contents and the remainder of the file can be injected as needed.

## Why does this exist?

[Pulsar][] uses [ikatyang/tree-sitter-markdown](https://github.com/ikatyang/tree-sitter-markdown) for Markdown files; it’s very robust, but lacks support for the [YAML front matter](https://jekyllrb.com/docs/front-matter/) convention popularized by Jekyll.

Instead of trying to add such support to a complex and intimidating Tree-sitter parser, I chose to write my own Tree-sitter parser instead, one whose only purpose is to separate a front matter block from other content in a file.

Pulsar uses this parser to divide a file into two parts. It then injects YAML syntax highlighting into the front matter (if present) and Markdown syntax highlighting into the remainder of the file.

## How does parsing work?

In lieu of a proper front-matter specification, I’ve tried to capture what seem to be the universal rules about a front matter block:

* The starting and ending delimiters are `---`s on lines by themselves. Trailing whitespace is allowed, but leading whitespace is not. If there is trailing non-whitespace content on the same line, the delimiter is ignored.

* The starting delimiter must be on the very first line of the file.

* The very next valid delimiter encountered is treated as the ending delimiter. All other content in the file — even another line that would count as a valid delimiter — is treated as the remainder, because the front matter block is complete.

* Any would-be front matter block that _opens_ but never _closes_ is not treated as a front matter block.

[Pulsar]: https://pulsar-edit.dev

[tree-sitter]: https://github.com/tree-sitter/tree-sitter