guile/test-suite/tests/structs.test

;;;; structs.test --- Test suite for Guile's structures.   -*- Scheme -*-
;;;; Ludovic Courtès <ludovic.courtes@laas.fr>, 2006-06-12.
;;;;
;;;; Copyright (C) 2006, 2007 Free Software Foundation, Inc.
;;;;
;;;; 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, 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 software; see the file COPYING.  If not, write to
;;;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;;;; Boston, MA 02110-1301 USA

(define-module (test-suite test-structs)
  :use-module (test-suite lib))



;;;
;;; Struct example taken from the reference manual (by Tom Lord).
;;;

(define ball-root (make-vtable-vtable "pr" 0))

(define (make-ball-type ball-color)
  (make-struct ball-root 0
	       (make-struct-layout "pw")
	       (lambda (ball port)
		 (format port "#<a ~A ball owned by ~A>"
			 (color ball)
			 (owner ball)))
	       ball-color))

(define (color ball) (struct-ref (struct-vtable ball) vtable-offset-user))
(define (owner ball) (struct-ref ball 0))
(define (set-owner! ball owner) (struct-set! ball 0 owner))

(define red (make-ball-type 'red))
(define green (make-ball-type 'green))

(define (make-ball type owner) (make-struct type 0 owner))



;;;
;;; Test suite.
;;;

(with-test-prefix "low-level struct procedures"

  (pass-if "constructors"
     (and (struct-vtable? ball-root)
	  (struct-vtable? red)
	  (struct-vtable? green)))

  (pass-if "vtables"
     (and (eq? (struct-vtable red) ball-root)
	  (eq? (struct-vtable green) ball-root)
	  (eq? (struct-vtable (make-ball red "Bob")) red)

	  ;; end of the vtable tower
	  (eq? (struct-vtable ball-root) ball-root)))

  (pass-if-exception "write-access denied"
     exception:struct-set!-denied

     ;; The first field of instances of BALL-ROOT is read-only.
     (struct-set! red vtable-offset-user "blue"))

  (pass-if "write-access granted"
     (set-owner! (make-ball red "Bob") "Fred")
     #t)

  (pass-if "struct-set!"
     (let ((ball (make-ball green "Bob")))
       (set-owner! ball "Bill")
       (string=? (owner ball) "Bill"))))


(with-test-prefix "equal?"

  (pass-if "simple structs"
     (let* ((vtable (make-vtable-vtable "pr" 0))
            (s1     (make-struct vtable 0 "hello"))
            (s2     (make-struct vtable 0 "hello")))
       (equal? s1 s2)))

  (pass-if "more complex structs"
     (let ((first (make-ball red (string-copy "Bob")))
           (second (make-ball red (string-copy "Bob"))))
       (equal? first second)))

  (pass-if "not-equal?"
     (not (or (equal? (make-ball red "Bob") (make-ball green "Bob"))
	      (equal? (make-ball red "Bob") (make-ball red "Bill"))))))


;;
;; make-struct
;;

(define exception:bad-tail
  (cons 'misc-error "tail array not allowed unless"))

(with-test-prefix "make-struct"

  ;; in guile 1.8.1 and earlier, this caused an error throw out of an
  ;; SCM_CRITICAL_SECTION_START / SCM_CRITICAL_SECTION_END, which abort()ed
  ;; the program
  ;;
  (pass-if-exception "wrong type for `u' field" exception:wrong-type-arg
    (let* ((vv (make-vtable-vtable "" 0))
	   (v  (make-struct vv 0 (make-struct-layout "uw"))))
      (make-struct v 0 'x)))

  ;; In guile 1.8.1 and earlier, and 1.6.8 and earlier, there was no check
  ;; on a tail array being created without an R/W/O type for it.  This left
  ;; it uninitialized by scm_struct_init(), resulting in garbage getting
  ;; into an SCM when struct-ref read it (and attempting to print a garbage
  ;; SCM can cause a segv).
  ;;
  (pass-if-exception "no R/W/O for tail array" exception:bad-tail
    (let* ((vv (make-vtable-vtable "" 0))
	   (v  (make-struct vv 0 (make-struct-layout "pw"))))
      (make-struct v 123 'x))))

;;
;; make-vtable
;;

(with-test-prefix "make-vtable"

  (pass-if "without printer"
    (let* ((vtable (make-vtable "pwpr"))
	   (struct (make-struct vtable 0 'x 'y)))
      (and (eq? 'x (struct-ref struct 0))
	   (eq? 'y (struct-ref struct 1)))))

  (pass-if "with printer"
    (let ()
      (define (print struct port)
	(display "hello" port))
	
      (let* ((vtable (make-vtable "pwpr" print))
	     (struct (make-struct vtable 0 'x 'y))
	     (str    (call-with-output-string
		      (lambda (port)
			(display struct port)))))
	 (equal? str "hello")))))


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