title: Eiffel: void safety, a concise way to test if an object exists and then call its feature
body: <p>I was wondering if there is a clearer statement then</p>
  
  <pre><code>if not attached foo then
      create foo
  end
  if attached foo as l_foo then
      l_foo.bark
  end
  </code></pre>
  
  <p>as </p>
  
  <pre><code>if not attached foo then
      create foo
      foo.bark
  else
      foo.bark
  end
  </code></pre>
  
  <p>would repeat the <code>foo.bark</code> and obviously I want to avoid it... and even the last statement won't compile with void-safety as foo on else could be void...</p>