title: Call function in another lisp file
body: <p>I have to write a game in Lisp. In order to make it clear, I wanted to split the code in different .lisp files.</p>
  
  <p>How can I call a function out of a function in the other file?</p>
  
  <p>E.g. file1.lisp has a function called function1 and file2.lisp has a function called function2.
  How can I call function2 out of function1?</p>
  
  <p>Thanks!</p>