KDL 2.0 grammar for tree-sitter

Adapted from the official KDL 2.0 spec

This grammar implements the KDL 2.0 specification with breaking changes from KDL 1.0.

Boolean and null values now require the # prefix:

// KDL 1.0
node true false null

// KDL 2.0
node #true #false #null

Raw strings use a new syntax with # delimiters instead of the r prefix:

// KDL 1.0
node r"raw string"
node r#"with hash"#

// KDL 2.0
node #"raw string"#
node ##"with hash"##

Support for triple-quoted multi-line strings:

node """
    This is a
    multi-line string
    """

Note: Opening delimiter must be followed immediately by a newline. Closing delimiter must be on its own line with optional leading whitespace.

• Removed: \/ (forward slash escape)
• Added: \s (space character U+0020)

// KDL 2.0 escapes
node "quote: \" backslash: \\ space: \s newline: \n"

Documents can optionally start with a version marker:

/- kdl-version 2

node "content"

Line continuations now support EOF:

node \

The Byte Order Mark (U+FEFF) is now only allowed as the first character in a document, not as general whitespace.

✅ Fully Implemented:

• Tagged literals (#true, #false, #null)
• Raw string syntax (#"..."#)
• String escape changes (\s added, \/ removed)
• Line continuation with EOF support
• Optional version marker
• BOM restrictions

🚧 In Progress:

• Multi-line string support (parser implemented, needs testing)
• Character validation for banned code points
• Test suite updates for KDL 2.0 syntax

To migrate KDL 1.0 documents to KDL 2.0:

1. Add # prefix to all boolean and null values
2. Change raw strings from r"..." to #"..."#
3. Replace \/ escapes with / (no escape needed)
4. Optionally use \s for explicit space escapes

See the original repository for installation instructions.