Range extraction: Difference between revisions

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@@ Line 1,728: / Line 1,728: @@
 Vanilla:
-<lang Lisp>(setq max-lisp-eval-depth 10000)
+<lang Lisp>(defun split-into-ranges (numbers)
+  (let* ((last-number (pop numbers))
+         (range (list last-number))
+         ranges)
+    (dolist (n numbers)
+      (if (= n (1+ last-number))
+          (push n range)
+        (push (nreverse range) ranges)
+        (setq range (list n)))
+      (setq last-number n))
+    (nreverse (cons (nreverse range) ranges))))
-(defun ab (a ls)
+(defun format-range (range)
+  (cond
-  (if ls (if (= (+ a 1) (car ls))
-	     (abc a (car ls) (cdr ls))
+   ((not range)
+    (error "invalid range"))
-	   (format "%d,%s" a (ab (car ls) (cdr ls))))
-    (format "%d" a)))
+   ((= (length range) 1)
+    (number-to-string (car range)))
+   ((= (length range) 2)
+    (format "%d,%d" (car range) (cadr range)))
+   (t
+    (format "%d-%d" (car range) (car (last range))))))
-(defun abc (a b ls)
+(defun rangext (numbers)
+  (mapconcat #'format-range (split-into-ranges numbers) ","))
-  (if ls (if (= (+ b 1) (car ls))
-	     (abcd a (car ls) (cdr ls))
-	   (format "%d,%d,%s" a b (ab (car ls) (cdr ls))))
-    (format "%d,%d" a b)))
-(defun abcd (a c ls)
-  (if ls (if (= (+ c 1) (car ls))
-	     (abcd a (car ls) (cdr ls))
-	   (format "%d-%d,%s" a c (ab (car ls) (cdr ls))))
-    (format "%d-%d" a c)))
-(defun rangext (ls)
-  (if ls (ab (car ls) (cdr ls)) ""))
 (rangext '(0  1  2  4  6  7  8  11 12 14