I wouldn&#x27;t recommend using infix libraries if you really want to get into Common Lisp though.  They&#x27;re a bit of a crutch for people coming from other languages, but that&#x27;s it.<p>Pretty much the whole language is based on Polish notation.  The sooner you realise that + - * &#x2F; are just function names like any other, the better you&#x27;ll do.<p>For example:<p><pre><code>  (+ 1 2 3)

  in plain symbols is just:

  (function parameter parameter parameter)
  
  But if I were to write my own addition function:

  (addition 1 2 3)

  it would also be:

  (function parameter parameter parameter)

  and so is:

  (http-request &quot;http:&#x2F;&#x2F;www.google.com&quot;)

  (function parameter)
</code></pre>
If you use infix notation, you&#x27;re writing half your code in a competely different semantic to the other half.  I can&#x27;t imagine it helping people really get a proper grasp of how Common Lisp works.