Ecko Language for VS Code

Language support for the Ecko programming language: a language server for smart editing, plus syntax highlighting and snippets.

Features

Language server (via the ecko binary - see Requirements):

• Live diagnostics as you type: parser errors, undefined names (with did-you-mean), arity mismatches, use-before-definition, non-exhaustive matches, unreachable code, unused imports/variables/functions, builtin shadowing, and unwrapped credentials
• Completion: keywords, builtins, std module names, your own top-level functions/types/variables, and each module's members after a .
• Hover: signatures for your functions, labels for builtins and modules
• Go-to-definition for your functions, types, and bindings
• Document symbols (outline / breadcrumbs) and workspace symbol search (jump to a symbol anywhere in the project)

Always available (no server needed):

• Full syntax highlighting for .ecko files, including string interpolation ("Hello, {name}!"), raw strings (r"..."), byte strings (b"\x89PNG"), decimal literals (19.99m), _ digit separators, bitwise word operators (band/bor/shl/…), sql { … } query blocks with {expr} bind holes, secrets builtins (secret/reveal/is_secret), contract and tool annotations (@requires, @ensures, @tool, @untrusted), ## documentation comments, type X = A | B unions, and the ai clauses (using, with, on, -> stream)
• Snippets for fn, template, match, for, ai, @ensures, sql, secret, and more
• Auto-closing brackets/quotes, folding via # region / # endregion, and indentation rules

Requirements

The smart-editing features are served by ecko lsp, so you need the ecko binary on your PATH (install it from https://ecko.sh). If it lives elsewhere, set ecko.server.path to its full path in your settings. Without the binary the extension still provides syntax highlighting and snippets, and shows a one-time notice explaining how to enable the rest.

Build and packaging

Prerequisites: Node.js / npm, and a VS Code-compatible editor (code or cursor) for installing the VSIX.

From this directory (editors/vscode-ecko under the language repo root):

# 1. Install extension dependencies (vscode-languageclient)
npm install

# 2. Install the VS Code Extension Manager (once per machine)
npm install -g @vscode/vsce

# 3. Package a VSIX from package.json version (e.g. 0.14.0 → vscode-ecko-0.14.0.vsix)
vsce package

# 4. Install into VS Code
code --install-extension vscode-ecko-0.14.0.vsix

For Cursor, use the same VSIX:

cursor --install-extension vscode-ecko-0.14.0.vsix

After installing or updating, reload the window (Developer: Reload Window) so the new grammar and client load.

Version bumps

1. Edit "version" in package.json.
2. Run vsce package again - the output filename follows vscode-ecko-<version>.vsix.
3. Reinstall with code --install-extension vscode-ecko-<version>.vsix (VS Code will replace the previous install for the same publisher/name).

What gets packaged

vsce package respects .vscodeignore. Source docs (*.md), VSIX artefacts, and test.ecko are excluded from the bundle. The shipped extension includes extension.js, package.json, the TextMate grammar, language configuration, snippets, and node_modules needed at runtime.

Optional: publish to the Marketplace

vsce login ecko          # once; needs a Personal Access Token
vsce publish             # publishes the version in package.json

Local VSIX install (above) is enough for development and private distribution.

Installation (pre-built VSIX)

If you already have a packaged file:

code --install-extension vscode-ecko-0.14.0.vsix