I feel like avoiding the use of LOOP could be a Master Foo koan. An ambitious young student of Lisp came to Master Foo, seeking to deepen her knowledge and und

I feel like avoiding the use of LOOP could be a Master Foo koan. An ambitious young student of Lisp came to Master Foo, seeking to deepen her knowledge and understanding. One day, during their studies and practice, the students stopped and said, "Master, I am troubled. In Lisp we have minimal syntax, and we use S-expressions to convey structure, and this syntactic uniformity gives us great power to build our own composable syntax constructs. And yet we have LOOP in the standard, which is an ad-hoc imitation of the same arbitrary syntax of other languages that we use Lisp in order to avoid!" The next day, the Master brought the student on a hike into the hills. As the sun was setting late in the afternoon, they reached a small cabin near the summit of a hill. A village of huts was visible in the valley below them. "Observe that this building is constructed from many small pieces of wood, each nearly uniform in size and shape. With those pieces I long ago built a hut that resembles the shoddy huts of the village, yet this one is both strong and easy to modify. You could even build it yourself from plans." The student observed and agreed, and was very impressed, but was also confused. "Master, what does this teach me about Lisp?" she asked. Master Foo continued, "You shall stay here on the mountain tonight. Return to me in the morning." With that, the Master drew a key from his robe, firmly locked the door of the cabin, and hiked away. As he did so, a cold rain and steady wind began to blow. The student spent the night cold and damp on the ground beside the cabin, and awoke enlightened.