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Common Lisp implementation running on the JVM
;;; sets.lisp
;;;
;;; Copyright (C) 2003-2005 Peter Graves
;;; $Id$
;;;
;;; This program is free software; you can redistribute it and/or
;;; modify it under the terms of the GNU General Public License
;;; as published by the Free Software Foundation; either version 2
;;; of the License, or (at your option) any later version.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software
;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
;;;
;;; As a special exception, the copyright holders of this library give you
;;; permission to link this library with independent modules to produce an
;;; executable, regardless of the license terms of these independent
;;; modules, and to copy and distribute the resulting executable under
;;; terms of your choice, provided that you also meet, for each linked
;;; independent module, the terms and conditions of the license of that
;;; module. An independent module is a module which is not derived from
;;; or based on this library. If you modify this library, you may extend
;;; this exception to your version of the library, but you are not
;;; obligated to do so. If you do not wish to do so, delete this
;;; exception statement from your version.
(in-package #:system)
;;; From CMUCL.
(defmacro with-set-keys (funcall)
`(cond (notp ,(append funcall '(:key key :test-not test-not)))
(t ,(append funcall '(:key key :test test)))))
(defun union (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(require-type list2 'list)
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((res list2))
(dolist (elt list1)
(unless (with-set-keys (member (funcall-key key elt) list2))
(push elt res)))
res))
(defmacro steve-splice (source destination)
`(let ((temp ,source))
(setf ,source (cdr ,source)
(cdr temp) ,destination
,destination temp)))
(defun nunion (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((res list2)
(list1 list1))
(do ()
((endp list1))
(if (not (with-set-keys (member (funcall-key key (car list1)) list2)))
(steve-splice list1 res)
(setf list1 (cdr list1))))
res))
(defun intersection (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((res nil))
(dolist (elt list1)
(if (with-set-keys (member (funcall-key key elt) list2))
(push elt res)))
res))
(defun nintersection (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((res nil)
(list1 list1))
(do () ((endp list1))
(if (with-set-keys (member (funcall-key key (car list1)) list2))
(steve-splice list1 res)
(setq list1 (cdr list1))))
res))
(defun set-difference (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(if (null list2)
list1
(let ((res nil))
(dolist (elt list1)
(if (not (with-set-keys (member (funcall-key key elt) list2)))
(push elt res)))
res)))
(defun nset-difference (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((res nil)
(list1 list1))
(do () ((endp list1))
(if (not (with-set-keys (member (funcall-key key (car list1)) list2)))
(steve-splice list1 res)
(setq list1 (cdr list1))))
res))
(defun set-exclusive-or (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(when key
(setq key (coerce-to-function key)))
(let ((result nil)
(key (when key (coerce key 'function)))
(test (coerce test 'function))
(test-not (if test-not (coerce test-not 'function) #'eql)))
(dolist (elt list1)
(unless (with-set-keys (member (funcall-key key elt) list2))
(setq result (cons elt result))))
(let ((test (if testp
(lambda (x y) (funcall test y x))
test))
(test-not (if notp
(lambda (x y) (funcall test-not y x))
test-not)))
(dolist (elt list2)
(unless (with-set-keys (member (funcall-key key elt) list1))
(setq result (cons elt result)))))
result))
;;; Adapted from SBCL.
(defun nset-exclusive-or (list1 list2 &key key (test #'eql testp) (test-not #'eql notp))
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(let ((key (and key (coerce-to-function key)))
(test (if testp (coerce-to-function test) test))
(test-not (if notp (coerce-to-function test-not) test-not)))
;; The outer loop examines LIST1 while the inner loop examines
;; LIST2. If an element is found in LIST2 "equal" to the element
;; in LIST1, both are spliced out. When the end of LIST1 is
;; reached, what is left of LIST2 is tacked onto what is left of
;; LIST1. The splicing operation ensures that the correct
;; operation is performed depending on whether splice is at the
;; top of the list or not.
(do ((list1 list1)
(list2 list2)
(x list1 (cdr x))
(splicex ())
(deleted-y ())
;; elements of LIST2, which are "equal" to some processed
;; earlier elements of LIST1
)
((endp x)
(if (null splicex)
(setq list1 list2)
(rplacd splicex list2))
list1)
(let ((key-val-x (apply-key key (car x)))
(found-duplicate nil))
;; Move all elements from LIST2, which are "equal" to (CAR X),
;; to DELETED-Y.
(do* ((y list2 next-y)
(next-y (cdr y) (cdr y))
(splicey ()))
((endp y))
(cond ((let ((key-val-y (apply-key key (car y))))
(if notp
(not (funcall test-not key-val-x key-val-y))
(funcall test key-val-x key-val-y)))
(if (null splicey)
(setq list2 (cdr y))
(rplacd splicey (cdr y)))
(setq deleted-y (rplacd y deleted-y))
(setq found-duplicate t))
(t (setq splicey y))))
(unless found-duplicate
(setq found-duplicate (with-set-keys (member key-val-x deleted-y))))
(if found-duplicate
(if (null splicex)
(setq list1 (cdr x))
(rplacd splicex (cdr x)))
(setq splicex x))))))
;;; Adapted from SBCL.
(defun subsetp (list1 list2 &key key (test #'eql testp) (test-not nil notp))
(require-type list2 'list)
(when (and testp notp)
(error "Both :TEST and :TEST-NOT were supplied."))
(let ((key (and key (coerce-to-function key))))
(dolist (elt list1)
(unless (with-set-keys (member (funcall-key key elt) list2))
(return-from subsetp nil)))
t))