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Ingy döt Net 2013-04-10 21:29:02 -07:00
parent 764da6cbbb
commit db842d013d
19005 changed files with 197040 additions and 7 deletions
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14
Task/Inverted-syntax/Common-Lisp/inverted-syntax-2.lisp Normal file
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(eval-when (:compile-toplevel :load-toplevel :execute)
(defun unrev-syntax (form)
(cond
((atom form) form) ;; atom: leave alone
((null (cdr form)) form) ;; one-element form: leave alone
((null (cddr form)) ;; two-element form: swap
(destructuring-bind (arg oper) form
`(,oper ,(unrev-syntax arg))))
(t ;; two or more args: swap last two, add others in reverse
(destructuring-bind (arg1 oper &rest args) (reverse form)
`(,oper ,(unrev-syntax arg1) ,@(mapcar #'unrev-syntax args)))))))
(defmacro rprogn (&body forms)
`(progn ,@(mapcar #'unrev-syntax forms)))