title: Is there a way to read a var passed and replace its value
body: <p>Is there a way to read a variable passed and replace its value.</p>
  
  <h2>less</h2>
  
  <pre><code>.mar(@B) when (default()) {
      margin:~'@{B}px';        
  }
  .mar(@A,@B){
      margin-@{A}:~'@{B}px';        
  }
  </code></pre>
  
  <h2>usage</h2>
  
  <pre><code>.foo1{
      .mar(3);
  }
  .foo2{
      .mar(t,3);
  }
  </code></pre>
  
  <p>the <strong>t</strong> value passed would be replaced by the word <strong>top</strong> and so worth for other letters, b for bottom, etc...</p>
  
  <p>I could pass the entire word <em>eg:top</em> but i'm trying to shorten the amount of text I type after the initial mixin.</p>