aoqi@0: /(?:[^[#\s\\]+|\\(?:[\S\s]|$)|\[\^?]?(?:[^\\\]]+|\\(?:[\S\s]|$))*]?)+|(\s*#[^\n\r\u2028\u2029]*\s*|\s+)([?*+]|{[0-9]+(?:,[0-9]*)?})?/g
aoqi@0: /{[0-9]+}?/g
aoqi@0: {123}
aoqi@0: {a}
aoqi@0: f{a}
aoqi@0: f
aoqi@0: SyntaxError
aoqi@0: SyntaxError