title: XML comments and "--"
body: <pre><code>&lt;!-- here is some comment --
                              ^
                              |
                      what can be here apart from '&gt;'?
  </code></pre>
  
  <p>XML seems not to like '--' inside comments. I read somewhere that '--' switchs some modes inside <code>&lt;! ... &gt;</code> thing, but <code>&lt;!-- -- -- --&gt;</code> (even number of <code>--</code>s) seem to be invalid too. If it is some historic feature, what is "pro" part of it? ("contra" part is inability to have <code>--</code> in comments).</p>
  
  <p>What is the reason of complicating comment processing by not making just '-->' end of comment and allowing '--' inside?</p>