Function reader

src/parser/token-reader.test.ts:9–13

* Helper to create a TokenReader from a string.

(input: string)

 * Helper to create a TokenReader from a string.
 */
function reader(input: string): TokenReader {
  const bytes = new TextEncoder().encode(input);

  return new TokenReader(new Scanner(bytes));
}

describe("TokenReader", () => {
  describe("whitespace and comments", () => {