Parsley XBNF for VS Code

Highlighting and language support for Parsley's .xbnf grammars.

• Colors: rule definitions and references, attributes, literals, regex patterns (classes, quantifiers and escapes), directives and comments. The C# in semantic actions is colored by VS Code's own C# grammar.
• Go to definition (F12), peek and find all references (Shift+F12) for rule names, across @imported files. References also cover any open grammar that imports this one.
• Highlights of every use of the rule under the cursor.
• Completion: rule names in expressions, attribute names and values (policy=, assoc= and so on) inside < >, and directives after @.
• Hover: a rule as written, with its action shortened to => { … }, and the // comments right above it. Attributes and directives get a one-line description.
• Diagnostics: syntax errors, undefined names and duplicate rules as you type. The full analysis (conflicts, lookahead, rewritten left recursion and so on) runs when you save and stays until the next edit. A problem in an imported file shows on its @import.
• Comment toggling, bracket matching and auto-closing pairs.

Requirements

The language features come from a .NET language server packed in the extension, which needs the .NET 8 runtime or later. Highlighting works without it.

Parsley: Restart XBNF Language Server restarts it.

Building

From this folder, with Node.js and the .NET 8 SDK:

npm install
npm run package

npm run package copies the grammar and language configuration from ../Parsley.VisualStudio/Grammars, publishes ../Parsley.LanguageServer into server/, bundles the extension into dist/ and writes parsley-xbnf-<version>.vsix. Install that with Extensions: Install from VSIX…, or run code --install-extension parsley-xbnf-1.0.0.vsix.

To try changes without packaging, run npm run prepare-assets and npm run build once, open this folder in VS Code and press F5.