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  1. (setq *atoms* '(a b c d e f))
  2.  
  3. (defun ordin (a1 a2 alst &optional (p1 nil) (p2 nil))
  4.   (cond ((null alst) nil)
  5.         ((eq (car alst) a1) (if p2 nil (ordin a1 a2 (cdr alst) t p2)))
  6.         ((eq (car alst) a2) (if p1 t nil))
  7.         (t (ordin a1 a2 (cdr alst) p1 p2))))
  8.  
  9. (princ (ordin 'b 'e *atoms*))
  10. (terpri)
  11. (princ (ordin 'e 'c *atoms*))
  12.  
Success #stdin #stdout 0s 535040KB
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https://ideone.com/zKW612
language:
Common Lisp (clisp 2.49.92)
created:
7 years ago
visibility:
public

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