title: D: finding all functions with certain attribute
body: <p>Is it currently possible to scan/query/iterate all functions (or classes) with some attribute across modules?</p>
  <p>For example:</p>
  <hr />
  <p><strong><code>source/packageA/something.d:</code></strong></p>
  <pre class="lang-d prettyprint-override"><code>@sillyWalk(10)
  void doSomething()
  {
  }
  </code></pre>
  <hr />
  <p><strong><code>source/packageB/anotherThing.d:</code></strong></p>
  <pre class="lang-d prettyprint-override"><code>@sillyWalk(50)
  void anotherThing()
  {
  }
  </code></pre>
  <hr />
  <p><strong><code>source/main.d:</code></strong></p>
  <pre class="lang-d prettyprint-override"><code>void main()
  {
      for (func; /* All @sillWalk ... */) {
          ...
      }
  }
  </code></pre>