In Clojure, how can I write my own recursive function to work with lazy lists?

I was just trying to demonstrate to someone laziness, and I wrote a simple recursive function to process the list.

I assumed it would be fine on an endless list. But all of a sudden I got an internal "too much recursion" error.

AND? I always write code that does this kind of thing. What is the problem?

But of course, I usually use built- map

in type functions as the basis for other list processing functions. This time I tried to write my own recursive traversal. And of course this may not work.

Here's what I wrote.

(defn q [xs] 
  (if (empty? xs) () 
    (cons (* (first xs) (first xs)) (q (rest xs)) )))

(take 10 (q (cycle '(1 2 3 4))))

      

        
        
        
      

    

So how do I actually write my own traversal functions that can handle lazy data structures in Clojure? Is there any equivalent to "profitability"?