21 lines
569 B
Common Lisp
21 lines
569 B
Common Lisp
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;;;; Ex 1.15
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;;; Write a predicate NOT-ONEP that return T if its input is anything other than one
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(defun not-onep (n)
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(not (equal n 1)))
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;;;; Ex 1.16
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;;; Write the predicate NOT-PLUSP that returns T if its input is not greater than zero
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(defun not-plusp (n)
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(not (> n 0)))
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;;;; Ex 1.17
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;;; Some earlier Lisp dialects did not have the EVENP primitive; they only had ODDP. Show how to define EVENP in terms of ODDP.
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(defun my-evenp (n)
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(not (oddp n)))
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;;;; Ex 1.20
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;;; Write XOR, the exclusive-or truth function.
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(defun xor (n m)
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(not (eq (not n) (not m))))
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