title: Is this possible with regular expressions?
body: <p>Something like this:</p>
  
  <pre><code>/[abcd]/[efgh]/
  </code></pre>
  
  <p>The idea is that <code>a</code> will get replaced with <code>e</code>, <code>b</code> with <code>f</code>, <code>c</code> with <code>g</code> and so on.</p>
  
  <p>Ideally, this should be language independent. If that isn't possible, I have an alternate solution (because this regex is generated by some code, I can make one for each of the possible replacements).</p>