Syntax highlighting, LSP diagnostics, completions, hover information, and document symbols for .cat files (CatLang / Catpile DSL).

Catpile is a Pythonic DSL that compiles to CatWeb JSON for Roblox CatWeb scripts. This extension provides a full editing experience for .cat files inside VS Code.

Catpile Docs • GitHub • PyPI • Web Editor

Requirements

catpile Python package installed in the Python environment VS Code uses:
```
pip install catpile
```
VS Code 1.85 or newer

Installation

From VS Code Marketplace

Search for "Catpile" in the Extensions view (Ctrl+Shift+X) and click Install, or run:

code --install-extension swirx.catpile

From VSIX

git clone https://github.com/SwirX/catpile-vscode.git
cd catpile-vscode
npm install
npx @vscode/vsce package
code --install-extension catpile-*.vsix

Configuration

Setting	Default	Description
`catpile.taste`	`indent`	`indent` (Pythonic) or `bracket` (JS-style `{ }`)
`catpile.defaultScope`	`local`	Default variable scope when no `l_`/`g_`/`o_` prefix
`catpile.pythonPath`	`python3`	Path to the Python interpreter with catpile installed
`catpile.lspLogLevel`	`warn`	Server log verbosity

Features

Syntax highlighting

Keywords: on, fn, script, if, else, repeat, foreach, break, return
Event names highlighted separately from action calls
Scope-prefixed variables (l_name, g_name, o_name) get distinct colouring
String interpolation {varname} inside "..." is highlighted
Both comment styles: # (indent taste) and // (bracket taste)
Dotted UI paths: page.element.sub

Diagnostics

Syntax errors from the parser reported inline with line + column
Unknown action name warnings (catches typos in action calls)
Unknown event name warnings (e.g. on laoded:)
Missing : at end of block headers (indent taste)

Completions

All 122 actions with full signature snippets (tab stops per parameter)
All 14 events with on <event>: snippets
Control-flow snippets: if, if/else, repeat, repeat_forever, foreach, fn, script
UI element path completions from .catui files in the workspace (triggered by .)
Variables seen in the current document

Hover

Hover over any action or event name to see:

Canonical name and schema id
Human-readable signature with slot types
UI path globalID (when hovering a dotted path)

Document symbols

The outline panel (Ctrl+Shift+O) shows:

script "Name" blocks as top-level containers
on <event> handlers
fn <name> function definitions

LSP server location

The extension ships a thin launcher at server/run_lsp.py that starts the LSP from catpile's installed package. The actual server logic lives in catpile/lsp.py.

To replace the built-in LSP with a newer version, update catpile/lsp.py in the catpile package and reinstall (pip install -e . works).

Commands

Command	Description
`Catpile: Restart Language Server`	Re-launches the LSP process
`Catpile: Show Server Output`	Opens the Catpile output channel

License

This extension is distributed under the GNU General Public License v3.0. See LICENSE for details.

Catpile - CatLang