CLHS: Section 3.7.2.1

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## 3.7.2.1 Examples of Transfer of Control during a Destructive Operation

The following examples illustrate some of the many ways in which the implementation-dependent nature of the modification can manifest itself.

     (let ((a (list 2 1 4 3 7 6 'five)))
       (ignore-errors (sort a #'<))
       a)
    =>  (1 2 3 4 6 7 FIVE)
    OR=>  (2 1 4 3 7 6 FIVE)
    OR=>  (2)

     (prog foo ((a (list 1 2 3 4 5 6 7 8 9 10)))
       (sort a #'(lambda (x y) (if (zerop (random 5)) (return-from foo a) (> x y)))))
    =>  (1 2 3 4 5 6 7 8 9 10)
    OR=>  (3 4 5 6 2 7 8 9 10 1)
    OR=>  (1 2 4 3)

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