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gadmyth/list to pairs

Last active December 21, 2015 08:19
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list to pairs
(defun pairs (x)
(labels ((pair-from-list (lst cum)
(let ((a (car lst)) (b (cadr lst)) (new-lst (cddr lst)))
(if (or (null a) (null b))
(reverse cum)
(progn
(pair-from-list new-lst (pushnew `(,a . ,b) cum)))))))
(pair-from-list x nil)))
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