Return values question

[def_pri_pub]

How does Nim return values from a proc? Are basic datatypes (like int and 
float) returned by copy? What about more complex structures like sequences and 
strings?

For example, would this proc: 
    
    
    proc fillWith(n, count: int): seq[int] =
      var s: seq[int] = @[]
      for i in countup(0, count - 1):
        s.add(n)
      
      return s
    

return what was instantiated on line 2? Or would it copy over the values to new 
sequence and return that to the caller? What about custom objects?