Add builder-method for snippet choice

src/vs/vscode.d.ts

@@ -2967,6 +2967,17 @@ declare module 'vscode' {
 		 */
 		appendPlaceholder(value: string | ((snippet: SnippetString) => any), number?: number): SnippetString;
 
+		/**
+		 * Builder-function that appends a choice (`${1|a,b,c}`) to
+		 * the [`value`](#SnippetString.value) of this snippet string.
+		 *
+		 * @param values The values for choices - the array of strings
+		 * @param number The number of this tabstop, defaults to an auto-increment
+		 * value starting at 1.
+		 * @return This snippet string.
+		 */
+		appendChoice(values: string[], number?: number): SnippetString;
+
 		/**
 		 * Builder-function that appends a variable (`${VAR}`) to
 		 * the [`value`](#SnippetString.value) of this snippet string.

src/vs/workbench/api/common/extHostTypes.ts

@@ -740,6 +740,18 @@ export class SnippetString {
 		return this;
 	}
 
+	appendChoice(values: string[], number: number = this._tabstop++): SnippetString {
+		const value = SnippetString._escape(values.toString());
+
+		this.value += '${';
+		this.value += number;
+		this.value += '|';
+		this.value += value;
+		this.value += '|}';
+
+		return this;
+	}
+
 	appendVariable(name: string, defaultValue?: string | ((snippet: SnippetString) => any)): SnippetString {
 
 		if (typeof defaultValue === 'function') {

src/vs/workbench/test/electron-browser/api/extHostTypes.test.ts

@@ -527,6 +527,25 @@ suite('ExtHostTypes', function () {
 		string.appendVariable('BAR', b => { });
 		assert.equal(string.value, '${BAR}');
 
+		string = new types.SnippetString();
+		string.appendChoice(['b', 'a', 'r']);
+		assert.equal(string.value, '${1|b,a,r|}');
+
+		string = new types.SnippetString();
+		string.appendChoice(['b', 'a', 'r'], 0);
+		assert.equal(string.value, '${0|b,a,r|}');
+
+		string = new types.SnippetString();
+		string.appendText('foo').appendChoice(['far', 'boo']).appendText('bar');
+		assert.equal(string.value, 'foo${1|far,boo|}bar');
+
+		string = new types.SnippetString();
+		string.appendText('foo').appendChoice(['far', '$boo']).appendText('bar');
+		assert.equal(string.value, 'foo${1|far,\\$boo|}bar');
+
+		string = new types.SnippetString();
+		string.appendText('foo').appendPlaceholder('farboo').appendChoice(['far', 'boo']).appendText('bar');
+		assert.equal(string.value, 'foo${1:farboo}${2|far,boo|}bar');
 	});
 
 	test('instanceof doesn\'t work for FileSystemError #49386', function () {