Dawn for VS Code

Language support for Dawn: a small, elegant functional language with immutable data, algebraic data types with exhaustive pattern matching, and effects written into the type signature.

• Syntax highlighting, brackets, comments and indentation.
• Diagnostics as you type, hover (types and signatures, default values included), signature help inside a call's argument list, go to definition, and the document outline, from the language server built into the Dawn compiler.
• Semantic highlighting from the same server: names are coloured by what they resolve to (function, constructor, constant, trait or effect, parameter), not by their case, and var bindings are underlined.

The front end does full error recovery, so a file that does not parse still reports all of its errors instead of stopping at the first one.

Requirements

This extension is a client. It does not carry a compiler, so install the Dawn toolchain and make sure dawn is on the PATH VS Code sees. The two shortest routes, both with the checksum the release publishes beside the artifact, are in the project README.

If dawn is not on VS Code's PATH, set Dawn: Lsp Path (dawn.lspPath) in settings to the absolute path of the executable. The extension runs <dawn.lspPath> lsp and speaks LSP over stdio.

The dawnc binary from the same release also answers lsp and can be used here, with the caveat that it is the C backend and refuses use java.

Settings

Building it yourself

The extension source is in editors/vscode. npm ci && npm test runs the TextMate scope contract, which asserts the grammar against a corpus using VS Code's own TextMate engine, and the semantic token contract, which checks the manifest's declarations against the server's legend; npm run package produces the .vsix.

License

Apache-2.0, the same as the rest of the repository.