add better sample for virtual documents

virtual-document-sample/src/cowsay.d.ts

@@ -0,0 +1,14 @@
+declare module 'cowsay' {
+
+    export interface CowsayOptions {
+        text: string;
+        cow?: string;
+        eyes?: string;
+        tongue?: string;
+        wrap?: boolean;
+        wrapLength?: number;
+        mode?: 'b' | 'd' | 'g' | 'p' | 's' | 't' | 'w' | 'y'
+    }
+
+    export function say(options: CowsayOptions): string;
+}

virtual-document-sample/src/extension.ts

@@ -0,0 +1,31 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------*/
+
+'use strict';
+
+import * as vscode from 'vscode';
+import * as cowsay from 'cowsay';
+
+export function activate({ subscriptions }: vscode.ExtensionContext) {
+
+	// register a content provider for the cowsay-scheme
+	const myScheme = 'cowsay';
+	const myProvider = new class implements vscode.TextDocumentContentProvider {
+		provideTextDocumentContent(uri: vscode.Uri): string {
+			// simply invoke cowsay, use uri-path as text
+			return cowsay.say({ text: uri.path });
+		}
+	}
+	subscriptions.push(vscode.workspace.registerTextDocumentContentProvider(myScheme, myProvider));
+
+	// register a command that opens a cowsay-document
+	subscriptions.push(vscode.commands.registerCommand('cowsay.say', async () => {
+		let what = await vscode.window.showInputBox({ placeHolder: 'cowsay...' });
+		if (what) {
+			let uri = vscode.Uri.parse('cowsay:' + what);
+			let doc = await vscode.workspace.openTextDocument(uri);
+			await vscode.window.showTextDocument(doc, { preview: false });
+		}
+	}));
+}