add hw2

node_modules/langium/lib/test/virtual-file-system.d.ts

@@ -0,0 +1,17 @@
+/******************************************************************************
+ * Copyright 2024 TypeFox GmbH
+ * This program and the accompanying materials are made available under the
+ * terms of the MIT License, which is available in the project root.
+ ******************************************************************************/
+import { URI } from 'vscode-uri';
+import type { FileSystemNode, FileSystemProvider } from '../workspace/file-system-provider.js';
+export declare class VirtualFileSystemProvider implements FileSystemProvider {
+    private readonly trie;
+    insert(uri: URI | string, content: string): void;
+    delete(uri: URI | string): void;
+    stat(uri: URI): Promise<FileSystemNode>;
+    statSync(uri: URI): FileSystemNode;
+    readFile(uri: URI): Promise<string>;
+    readDirectory(uri: URI): Promise<FileSystemNode[]>;
+}
+//# sourceMappingURL=virtual-file-system.d.ts.map