4.7 Loop Facility

A common complaint with Lisp’s traditional looping constructs is that they are either too simple and limited, such as Common Lisp’s dotimes or Emacs Lisp’s while, or too unreadable and obscure, like Common Lisp’s do loop.

To remedy this, recent versions of Common Lisp have added a new construct called the “Loop Facility” or “loop macro,” with an easy-to-use but very powerful and expressive syntax.