Hexaly

zed-hexaly

Hexaly language support for Zed — syntax highlighting for Hexaly Modeler models (.hxm).

Ships a purpose-built tree-sitter grammar for the language, because none existed publicly: tree-sitter-hexaly. Zed cannot use the TextMate grammar from the official Hexaly VS Code extension, so highlighting had to be rebuilt on tree-sitter.

Status

Syntax highlighting, plus a language server (hexaly-lsp) providing diagnostics, completion, hover and signature help.

What works today:

• Highlighting of modeling constructs — constraint, minimize/maximize, the <- decision operator, indexed declarations over an index space, and sum/min/max aggregates
• Bracket matching, auto-indent, and text objects
• An outline listing model decisions alongside functions, since in a Hexaly model the decisions are the structure
• Diagnostics: every syntax error at once from the grammar, and structural errors (duplicate declarations, unresolvable use) from a local Hexaly installation when there is one
• Completion, hover and signature help over 396 standard-library symbols and the declarations in the file being edited

Install

Not yet in the Zed extension registry. To use it now, install as a dev extension:

1. Clone this repository
2. In Zed, run zed: install dev extension from the command palette
3. Select the cloned directory

The language server is downloaded automatically on first use — no Rust toolchain and no separate install step. If you would rather supply your own build, one on $PATH or at ~/.cargo/bin/hexaly-lsp is preferred over the download, so cargo install --git https://github.com/ashenwolf/hexaly-lsp keeps working and wins. An explicit path overrides everything:

{
  "lsp": {
    "hexaly-lsp": { "binary": { "path": "/path/to/hexaly-lsp" } }
  }
}

On a remote (SSH) project the server runs on the remote host, and the extension downloads it there. If you set an explicit path instead, put it in that project's .zed/settings.json rather than your global settings, which are shared with local projects and would point at the wrong filesystem.

Diagnostics from the Hexaly compiler need a Hexaly installation but no licence; without one the server reports so and continues with everything else.

Development

This repository holds the Zed queries in languages/hexaly and the extension itself in src/. The extension is deliberately thin: it answers "where is the language server binary" and nothing else. Everything about the language lives in hexaly-lsp, which speaks plain LSP over stdio and is not Zed-specific, so the same server serves Neovim, Helix and Emacs.

Notably absent from the extension: locating the Hexaly installation. Zed offers worktree.which(), which would work here and would also strand every other editor, so the server discovers Hexaly itself.

cargo build --release --target wasm32-wasip1   # what Zed loads

The grammar is a separate repository, tree-sitter-hexaly, pinned by rev in extension.toml: Zed clones it and compiles its generated src/parser.c directly, so keeping it apart is what keeps generated C out of this repo. A grammar change means landing it there and bumping rev here.

The grammar was validated by parsing a production Hexaly model (12 files, ~2500 lines) and all 66 example models shipped with Hexaly 14.0 with zero errors, and corrected against the official HXM BNF and the compiler itself; the findings from those passes are kept in the grammar repository's docs/.

License

MIT — see LICENSE. Not affiliated with or endorsed by Hexaly.