Function interp_deque 

fn interp_deque(
    _args: &[RValue],
    _named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Create an empty deque (double-ended queue of R values).

Returns an integer ID with class “deque”. Use deque_push_back(), deque_push_front(), deque_pop_back(), deque_pop_front() to manipulate it.

@return integer scalar with class “deque”