title: Nginx url arg parsing with dashes
body: <p>I recently upgraded from nginx version 1.8 to 1.12, and I noticed that the map module has changed. The following works in 1.8, but no longer works in 1.12. </p>
  
  <pre><code>map $is_args $foo {
      default $arg_foo-bar
  }
  </code></pre>
  
  <p>Instead, I have to remove the dash to get it to work properly.</p>
  
  <pre><code>map $is_args $foo {
      default $arg_foo_bar
  }
  </code></pre>
  
  <p>I can't find anything in the change logs to explain this.</p>
  
  <p>Edit: I tested the foo-bar variable in 1.10, and it works.</p>