title: Using LESS mixin to set variable multiple times but getting wrong results
body: <p>At the front, I started with less today...</p>
  
  <p>So any advice how to do that better is welcome!</p>
  
  <p>I have following .less file:</p>
  
  <pre><code>.test(@target;@context) {
    @em: (@target / @context) * 1em;
  }
  
  .custom-field {
    position: relative;
    .test(30;16);
    padding-bottom: @em;
    .test(30;16);
    margin-bottom: @em;
    .test(320;16);
    max-width: @em;
  }
  </code></pre>
  
  <p>I expect that padding-bottom and margin-bottom getting the value 1.875 and max-width: 20.</p>
  
  <p>But thats the output:</p>
  
  <pre><code>.custom-field {
    position: relative;
    padding-bottom: 1.875em;
    margin-bottom: 1.875em;
    max-width: 1.875em;
  }
  </code></pre>
  
  <p>I had the second parameter as an optional parameter at the start. But for testing I made it as simple as possible.</p>
  
  <p>If I use the mixin even more often, I get a lot more weird results. At least for me they are weird :)</p>
  
  <p>Has anyone an advice for me?</p>