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72 irasnyd 1 
irasnyd@duallie lisp $ cat hw12.lisp
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;Written By: Ira Snyder
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;Due Date:   02-28-2005
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;Homework #: HW12
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;;; This is the generic implementation of the recursive schema OP-SOME.
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;;; It takes 3 parameters:
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;;;   CONDITION: when this is true, the operation happens on that element
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;;;   OP: the operation to happen on the values that satisfy CONDITION
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;;;   ARG: the list of items on which to operate
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;;;
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;;; Example: (OP-SOME #'oddp #'sq '(1 2 3 4 5)) -> (1 2 9 4 25)
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(defun OP-SOME (CONDITION OP ARG)
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  (cond
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    ((null ARG)                    nil)
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    ((funcall CONDITION (car ARG)) (cons (funcall OP (car ARG))
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                                         (OP-SOME CONDITION OP (cdr ARG))))
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    (t                             (cons (car ARG)
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                                         (OP-SOME CONDITION OP (cdr ARG))))
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  )
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)
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;;; Returns the square of the number passed in as a parameter.
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;;; This is to aid in testing of OP-SOME
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(defun SQ (NUM)
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  (* NUM NUM)
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)
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irasnyd@duallie lisp $ clisp -q
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[1]> (load 'hw12.lisp)
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;; Loading file hw12.lisp ...
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;; Loaded file hw12.lisp
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T
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[2]> (OP-SOME #'oddp #'SQ nil)
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NIL
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[3]> (OP-SOME #'oddp #'SQ '(2))
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(2)
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[4]> (OP-SOME #'oddp #'SQ '(3))
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(9)
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[5]> (OP-SOME #'oddp #'SQ '(3 6 4 5 2))
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(9 6 4 25 2)
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[6]> (bye)
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irasnyd@duallie lisp $
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