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Re: goops - guile-clutter unexpected bug while using #:virtual slot allo
From: |
David Pirotte |
Subject: |
Re: goops - guile-clutter unexpected bug while using #:virtual slot allocation for a <clutter-actor> subclass |
Date: |
Sat, 7 Feb 2015 14:08:12 -0200 |
Hello Andy,
> > With the stable-2.0 or master branches, the current behavior is:
> >
> > scheme@(guile-user)> (use-modules (oop goops))
> > scheme@(guile-user)> (define-class <a> ()
> > ... (foo #:getter foo #:init-keyword #:foo))
> > scheme@(guile-user)> (define-class <b> (<a>))
> > scheme@(guile-user)> (define obj (make <b> #:foo 34))
> > scheme@(guile-user)> (define-method (foo (self <b>))
> > ... (pk "ahoy!")
> > ... (next-method))
> > scheme@(guile-user)> (pk (foo obj))
> >
> > ;;; ("ahoy!")
> > ERROR: In procedure scm-error:
> > ERROR: No next method when calling #<<generic> foo (2)>
> > with arguments (#<<b> 2c207e0>)
> >
> > Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue.
> > scheme@(guile-user) [1]>
>
> Yes, expected, but to me, it is because of what I just said here below.
>
> > > In this case indeed, the only method that exists and is applicable is
> > > the getter foo that <a> defines and<b> inherits: there is no
> > > next-method and calling (next-method) would be a user bug, in my
> > > opinion too.
> >
> > So, we should be precise with terminology :) In GOOPS, subclasses do
> > not inherit accessor methods. (There was a bug in which they would; I
> > fixed that.) Each subclass gets its own accessor method defined, if and
> > only if it has the corresponding slot, and that method is not inherited.
Some are, some are not...:
;;; module a.scm starts here
(define-module (a)
#:use-module (oop goops)
#:export (<a>
!v
!width
set-width))
(define-class <a> ()
(v #:accessor !v
#:init-keyword #:v
#:allocation #:virtual
#:slot-ref (lambda (self)
(pk "this is <a> v slot-ref, hello!"))
#:slot-set! (lambda (self value)
(pk "this is <a> v slot-set!, hello!")))
(width #:accessor !width #:init-keyword #:width #:init-value 0))
(define-method ((setter !width) (self <a>) width)
(set-width self width))
(define-method (set-width (self <a>) width)
;; here comes complex code, computing earth orbit, captain's age...
(pk "this is <a> !width setter method, hello!")
(slot-set! self 'width width)
width)
;;; module ends here
;;; module b.scm starts here
(define-module (b)
#:use-module (oop goops)
#:use-module (a)
#:export (<b>)
#:re-export (!v
!width
set-width))
(define-class <b> (<a>))
;;; module ends here
GNU Guile 2.0.11.114-649ec
Copyright (C) 1995-2014 Free Software Foundation, Inc.
Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.
Enter `,help' for help.
scheme@(guile-user)>
scheme@(guile-user)> ,use (oop goops)
scheme@(guile-user)> ,use (b)
;;; note: source file ./b.scm
;;; newer than compiled
/home/david/.cache/guile/ccache/2.0-LE-8-2.0/usr/alto/projects/guile-tests/goops/setter-inheritance-bug/b.scm.go
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;; or pass the --no-auto-compile argument to disable.
;;; compiling ./b.scm
;;; note: source file ./a.scm
;;; newer than compiled
/home/david/.cache/guile/ccache/2.0-LE-8-2.0/usr/alto/projects/guile-tests/goops/setter-inheritance-bug/a.scm.go
;;; compiling ./a.scm
;;; compiled
/home/david/.cache/guile/ccache/2.0-LE-8-2.0/usr/alto/projects/guile-tests/goops/setter-inheritance-bug/a.scm.go
;;; compiled
/home/david/.cache/guile/ccache/2.0-LE-8-2.0/usr/alto/projects/guile-tests/goops/setter-inheritance-bug/b.scm.go
scheme@(guile-user)> (make <b>)
$2 = #<<b> 2334760>
scheme@(guile-user)> (!v $2)
;;; ("this is <a> v slot-ref, hello!")
$3 = "this is <a> v slot-ref, hello!"
scheme@(guile-user)> (set! (!v $2) 'blue)
;;; ("this is <a> v slot-set!, hello!")
$4 = "this is <a> v slot-set!, hello!"
scheme@(guile-user)> (set! (!width $2) 10)
$5 = 10
scheme@(guile-user)>
Cheers,
David
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