🐛 revert changes from #31 as they break tests

Author: codereport

main.rkt

@@ -102,16 +102,16 @@
 
 
 (define (sliding lst size [step 1])
-  (when (or (<= step 0) (> step (length lst)))
-    (error "step has to be equal to or smaller than the length of the list"))
-
-  (let recur [(lst lst)
-              (len (length lst))]
-    (if (>= len size)
-      (cons (take lst size)
-            (recur (drop lst step)
-                   (- len step)))
-      empty)))
+  (define (tail-call lst)
+    (if (>= size (length lst))
+        (list lst)
+        (cons (take lst size)
+              (tail-call (drop lst step)))))
+  (cond
+    [(> step (length lst))
+      (error "step has to be equal to or smaller than length of the list")]
+    [(= step (length lst)) (list lst)]
+    [else (tail-call lst)]))
 
 
 (define (scanl proc lst)