feat(lsp): initial stub for server and client

package.json

@@ -81,5 +81,9 @@
     "eslint": "^8.57.0",
     "js-yaml": "^4.1.0",
     "typescript": "^5.3.3"
+  },
+  "dependencies": {
+    "vscode-languageclient": "^9.0.1",
+    "vscode-languageserver": "^9.0.1"
   }
 }

src/extension.ts

@@ -1,26 +1,63 @@
-// The module 'vscode' contains the VS Code extensibility API
-// Import the module and reference it with the alias vscode in your code below
-import * as vscode from 'vscode';
+import * as path from "path";
 
-// This method is called when your extension is activated
-// Your extension is activated the very first time the command is executed
-export function activate(context: vscode.ExtensionContext) {
+import * as vscode from "vscode";
+import {
+  LanguageClient,
+  LanguageClientOptions,
+  ServerOptions,
+  TransportKind,
+} from "vscode-languageclient/node";
+
+let client: LanguageClient;
 
-	// Use the console to output diagnostic information (console.log) and errors (console.error)
-	// This line of code will only be executed once when your extension is activated
-	console.log('Congratulations, your extension "stencila" is now active!');
+/**
+ * Activate the extension
+ */
+export function activate(context: vscode.ExtensionContext) {
+  // Use the console to output diagnostic information (console.log) and errors (console.error)
+  // This line of code will only be executed once when your extension is activated
+  console.log('Congratulations, your extension "stencila" is now active!');
 
-	// The command has been defined in the package.json file
-	// Now provide the implementation of the command with registerCommand
-	// The commandId parameter must match the command field in package.json
-	let disposable = vscode.commands.registerCommand('stencila.helloWorld', () => {
-		// The code you place here will be executed every time your command is executed
-		// Display a message box to the user
-		vscode.window.showInformationMessage('Hello World from Stencila!');
-	});
+  // The command has been defined in the package.json file
+  // Now provide the implementation of the command with registerCommand
+  // The commandId parameter must match the command field in package.json
+  let disposable = vscode.commands.registerCommand(
+    "stencila.helloWorld",
+    () => {
+      // The code you place here will be executed every time your command is executed
+      // Display a message box to the user
+      vscode.window.showInformationMessage("Hello World from Stencila!");
+    }
+  );
+  context.subscriptions.push(disposable);
 
-	context.subscriptions.push(disposable);
+  // Start the language server client
+  const serverModule = context.asAbsolutePath(path.join("out", "server.js"));
+  const serverOptions: ServerOptions = {
+    run: { module: serverModule, transport: TransportKind.ipc },
+    debug: {
+      module: serverModule,
+      transport: TransportKind.ipc,
+    },
+  };
+  const clientOptions: LanguageClientOptions = {
+    documentSelector: [{ scheme: "file", language: "smd" }],
+  };
+  client = new LanguageClient(
+    "stencila",
+    "Stencila",
+    serverOptions,
+    clientOptions
+  );
+  client.start();
 }
 
-// This method is called when your extension is deactivated
-export function deactivate() {}
+/**
+ * Deactivate the extension
+ */
+export function deactivate() {
+  if (!client) {
+    return undefined;
+  }
+  return client.stop();
+}

src/server.ts

@@ -0,0 +1,28 @@
+/**
+ * A module to run the Stencila language server from within Node.js
+ *
+ * Rather than bundling the Stencila CLI binary with this VSCode extension
+ * and spawning `stencila lsp` this script calls Stencila LSP functions
+ * exposed by the `@stencila/node` bindings. This has two main advantages:
+ *
+ * - distributing `@stencila/node` is easier than distributing `stencila` binaries
+ *
+ * - we can prototype interactions between VSCode and the Stencila language server
+ *   i.e. event handlers in this module act as mocks for what the Rust-based
+ *   language server function will implement
+ */
+
+import { createConnection } from "vscode-languageserver/node";
+
+// Custom logging functions for better visibility in server outputs
+const debug = (...args: any[]) => process.stderr.write(`DEBUG ${JSON.stringify(args)}`);
+const info = (...args: any[]) => process.stderr.write(`INFO ${JSON.stringify(args)}`);
+const warning = (...args: any[]) => process.stderr.write(`WARN ${JSON.stringify(args)}`);
+const error = (...args: any[]) => process.stderr.write(`ERROR ${JSON.stringify(args)}`);
+
+// Create a connection for the server, using Node's IPC as a transport.
+const connection = createConnection();
+
+// Listen on the connection
+info("Listening on LSP connection");
+connection.listen();