Reference to sequence

[dataPulverizer]

How do you create a reference to a sequence? I can see how you create a pointer 
to a sequence:
    
    
    var x: seq[float64] = @[1.0,  2, 3, 4, 5];
    var y = x.addr;
    
    
    Run

But have no idea how to create ref seq[float64], or is it only possible to 
create a ptr seq[float] while the ref keyword is only really used when defining 
objects?

Thanks in advance.