Editor VS Code

VS Code

Lexicon does not currently ship a first-party VS Code extension. VS Code can still use lexicon-lsp, but it needs a language-client extension because VS Code does not attach arbitrary stdio language servers from settings alone.

Use one of these approaches:

• Recommended for product use: create a thin workspace or project extension using vscode-languageclient.
• Fast experiment: use a generic LSP client extension and point it at lexicon-lsp.
• Baseline without LSP: use CLI validation tasks.

1. Build the Language Server

swift build -c release --product lexicon-lsp

Keep the absolute path:

/absolute/path/to/Lexicon/.build/release/lexicon-lsp

2. Add Project Configuration

At the workspace root:

{
  "lexicon": "lexicons/commerce.lexicon"
}

Save it as lexicon-lsp.json.

3. Thin VS Code Extension

Create a small extension that registers .lexicon, Go, and Rust documents with lexicon-lsp.

package.json:

{
  "name": "lexicon-vscode",
  "displayName": "Lexicon",
  "version": "0.0.1",
  "engines": { "vscode": "^1.90.0" },
  "activationEvents": [
    "onLanguage:lexicon",
    "onLanguage:go",
    "onLanguage:rust"
  ],
  "contributes": {
    "languages": [
      {
        "id": "lexicon",
        "aliases": ["Lexicon"],
        "extensions": [".lexicon"]
      }
    ],
    "configuration": {
      "title": "Lexicon",
      "properties": {
        "lexicon.languageServer.path": {
          "type": "string",
          "default": "lexicon-lsp"
        }
      }
    }
  },
  "main": "./out/extension.js",
  "dependencies": {
    "vscode-languageclient": "^9.0.1"
  },
  "devDependencies": {
    "@types/vscode": "^1.90.0",
    "typescript": "^5.0.0"
  }
}

src/extension.ts:

import * as vscode from "vscode";
import {
  LanguageClient,
  LanguageClientOptions,
  ServerOptions
} from "vscode-languageclient/node";

let client: LanguageClient | undefined;

export function activate(context: vscode.ExtensionContext) {
  const config = vscode.workspace.getConfiguration("lexicon");
  const command = config.get<string>("languageServer.path") || "lexicon-lsp";

  const serverOptions: ServerOptions = { command };
  const clientOptions: LanguageClientOptions = {
    documentSelector: [
      { scheme: "file", language: "lexicon" },
      { scheme: "file", language: "go" },
      { scheme: "file", language: "rust" }
    ]
  };

  client = new LanguageClient("lexicon-lsp", "Lexicon LSP", serverOptions, clientOptions);
  context.subscriptions.push(client);
  client.start();
}

export function deactivate(): Thenable<void> | undefined {
  return client?.stop();
}

Build and launch the extension in an Extension Development Host using the workflow from VS Code's official Language Server Extension Guide.

Workspace settings:

{
  "lexicon.languageServer.path": "/absolute/path/to/Lexicon/.build/release/lexicon-lsp"
}

4. Generic LSP Client Option

For experimentation, install a generic LSP client extension from the Marketplace and configure it to launch lexicon-lsp over stdio.

This is useful for testing, but a dedicated extension is better for team use because it can:

• register .lexicon as a language
• control activation
• choose the exact document selectors
• provide workspace settings
• include tasks and troubleshooting commands

5. CLI Tasks Without LSP

Even without editor LSP support, add validation tasks.

.vscode/tasks.json:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "lexicon: lint",
      "type": "shell",
      "command": "swift run lexicon lint lexicons/commerce.lexicon",
      "group": "test",
      "problemMatcher": []
    },
    {
      "label": "lexicon: generate",
      "type": "shell",
      "command": "swift run lexicon-generate lexicons/commerce.lexicon --type ts -o src/generated/commerce-lexicon",
      "group": "build",
      "problemMatcher": []
    }
  ]
}

What Works

With a client attached, lexicon-lsp provides completions and diagnostics in:

• .lexicon references
• Go l("...") exact-path calls
• Rust l!(...) exact-path macros

Normal VS Code language extensions continue to handle Go, Rust, and TypeScript language features.