title: Why can't a variable name end with `?` while a method name can?
body: <p>A method name can end with a question mark <code>?</code></p>
  
  <pre><code>def has_completed?
    return count &gt; 10
  end
  </code></pre>
  
  <p>but a variable name cannot.</p>
  
  <p>What is the reason for that?  Isn't it convenient to have variable names ending the same way too? Given that we usually can't tell whether <code>foobar</code> is a method or a variable just by looking at the name <code>foobar</code> anyway, why the exception for the <code>?</code> case?</p>
  
  <p>And how should I work with this? Maybe always to use <code>has</code> or <code>is</code> in the code?</p>
  
  <pre><code>if process_has_completed
    ...
  end
  
  if user_is_using_console
    ...
  end
  </code></pre>