proc `$`(rs: RefString): lent string {....raises: [], tags: [], forbids: [].}

proc fromJS(ctx: JSContext; val: JSValueConst; rs: var RefString): FromJSResult {.
    ...raises: [], tags: [], forbids: [].}

proc len(rs: RefString): int {....raises: [], tags: [], forbids: [].}

proc newRefString(s: sink string): RefString {....raises: [], tags: [], forbids: [].}

proc toJS(ctx: JSContext; rs: RefString): JSValue {....raises: [], tags: [],
    forbids: [].}

template `&=`(rs: var RefString; ss: string)

template `[]`(rs: RefString; i: int): char