Tree sitter grammar for CFEngine policy language

This tree-sitter grammar parses CFEngine policy language and turns it into an abstract syntax tree. It is used to provide syntax highlighting in the Zed editor, via this extension:

https://github.com/olehermanse/zed-cfengine

The grammar currently supports all major features of the language, including:

• Bundle blocks
• Body blocks
• Promise type definition blocks
• Promise types, class guards, promises, stakeholders (promisees)
• Macros
• Function calls
• Lists, strings, expansions (with $() and @())

Todos

• Using the grammar for linting / syntax checking (language server)
• Highlighting inside strings and comments
• Recognizing when there is JSON inside policy
• Class guards which are quoted strings
• Using the grammar for code indentation
• Using the grammar for extensions to other editors

Before contributing for the first time, it's recommended to go through the tree-sitter tutorial for getting familiar with how everything works:

https://tree-sitter.github.io/tree-sitter/creating-parsers

Inspired by Lars Erik Wik's initial implementation available here:

https://github.com/larsewi/tree-sitter-cfengine

Run containerized tests locally:

docker build --tag tree-sitter-cfengine .