title: Creating default function parameters
body: <p>Is there a way to create <em>pseudo</em> default function parameters in rust? I'd like to do something like</p>
  
  <pre><code>pub struct Circular&lt;T&gt; {
      raw: Vec&lt;T&gt;,
      current: u64
  }
  
  impl&lt;T&gt; Circular&lt;T&gt; {
      pub fn new(t_raw: Vec&lt;T&gt;, t_current=0: u64) -&gt; Circular&lt;T&gt; {
          return Circular { raw: t_raw, current: t_current };
      }
  </code></pre>
  
  <p>I'd like to have the option of settings the <code>current</code> variable, but it won't always be needed to be set. Is this a possible thing to do in Rust?</p>