title: Clear a sequence in Nim
body: <p>What is the Nim equivalence of <code>List.Clear</code> in languages like java or c# for sequences? I see listed in system the proc <code>setLen</code>, but im not sure it does what i want. From the description:</p>
  
  <p><code>f the current length is greater than the new length, s will be truncated. s</code></p>
  
  <p>Does it mean everytime i set any seq len to 0 it will create a new instance of seq?</p>