* Implements languageId support

* Implements typing of helper functions
* Shift+F1 opens a new debug visualizer window if none is opened yet

extension/src/EvaluationWatchService/EvaluationEngine/EvaluationEngine.ts

@@ -16,6 +16,11 @@ export interface Evaluator {
 		| { kind: "data"; result: DataExtractionResult }
 		| { kind: "error"; message: FormattedMessage }
 	>;
+
+	/**
+	 * The language that expressions must be written in.
+	 */
+	readonly languageId: string | undefined;
 }
 
 export interface EvaluationArgs {

extension/src/EvaluationWatchService/EvaluationEngine/GenericEvaluationEngine.ts

@@ -22,6 +22,8 @@ export class GenericEvaluationEngine implements EvaluationEngine {
 }
 
 export class GenericEvaluator implements Evaluator {
+	public readonly languageId = "text";
+
 	constructor(private readonly session: VsCodeDebugSession) {}
 
 	public async evaluate({

extension/src/EvaluationWatchService/EvaluationEngine/JsEvaluationEngine.ts

@@ -33,6 +33,8 @@ export class JsEvaluationEngine implements EvaluationEngine {
 }
 
 class JsEvaluator implements Evaluator {
+	public readonly languageId = "javascript";
+
 	constructor(private readonly session: VsCodeDebugSession) {}
 
 	public async evaluate({