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equals.scm
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1999-01-02
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#| -*-Scheme-*-
$Id: equals.scm,v 14.8 1999/01/02 06:11:34 cph Exp $
Copyright (c) 1988-1999 Massachusetts Institute of Technology
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|#
;;;; Equality
;;; package: ()
(declare (usual-integrations))
(define (eqv? x y)
;; EQV? is officially supposed to work on booleans, characters, and
;; numbers specially, but it turns out that EQ? does the right thing
;; for everything but numbers, so we take advantage of that.
(or (eq? x y)
(if (object-type? (object-type x) y)
(and (not (fix:fixnum? x))
(if (number? y)
(and (= x y)
(boolean=? (exact? x) (exact? y)))
(and (object-type? (ucode-type vector) y)
(fix:zero? (vector-length x))
(fix:zero? (vector-length y)))))
(and (number? x)
(number? y)
(= x y)
(boolean=? (exact? x) (exact? y))))))
(define (equal? x y)
(or (eq? x y)
(if (object-type? (object-type x) y)
(cond ((pair? y)
(and (equal? (car x) (car y))
(equal? (cdr x) (cdr y))))
((vector? y)
(let ((size (vector-length x)))
(and (fix:= size (vector-length y))
(let loop ((index 0))
(or (fix:= index size)
(and (equal? (vector-ref x index)
(vector-ref y index))
(loop (fix:+ index 1))))))))
((string? y)
(string=? x y))
((number? y)
(and (= x y)
(boolean=? (exact? x) (exact? y))))
((cell? y)
(equal? (cell-contents x) (cell-contents y)))
((bit-string? y)
(bit-string=? x y))
((pathname? x)
(and (pathname? y)
(pathname=? x y)))
(else false))
(and (number? x)
(number? y)
(= x y)
(boolean=? (exact? x) (exact? y))))))