Move initialization of attribute object
[clinton/lisp-on-lines.git] / src / display.lisp
1 (in-package :lisp-on-lines)
2
3 (defvar *description*)
4 (defvar *display*)
5 (defvar *object*)
6
7 (deflayer display-layer)
8
9 (define-layered-function display-using-description (description display object &rest args)
10 (:documentation
11 "Displays OBJECT via description using/in/with/on display"))
12
13 (defun display (display object &rest args)
14 (display-using-description (description-of object) display object args))
15
16 (define-layered-method display-using-description
17 :around (description display object &rest args)
18 (declare (ignorable args))
19 (let ((*description* description)
20 (*display* display)
21 (*object* object))
22
23 (call-next-method)))
24
25
26
27 (define-layered-method display-using-description (description display object &rest args)
28 (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~% DESCRIPTION: ~A ~% DISPLAY: ~A ~% OBJECT: ~A ~% ARGS: ~S
29
30 OMGWTF! If you didn't do this, it's a bug!" description display object args))
31
32
33
34 (defmacro define-display (&body body)
35 (loop with in-descriptionp = (eq (car body) :in-description)
36 with description = (if in-descriptionp (cadr body) 't)
37 for tail on (if in-descriptionp (cddr body) body)
38 until (listp (car tail))
39 collect (car tail) into qualifiers
40 finally
41 (when (member :in-description qualifiers)
42 (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
43 (return
44 (destructuring-bind (description-spec &optional (display-spec (gensym)) (object-spec (gensym)))
45 (car tail)
46 `(define-layered-method
47 display-using-description
48 :in-layer ,(if (eq t description)
49 t
50 (defining-description description))
51 ,@qualifiers
52 (,(if (listp description-spec)
53 (list (first description-spec)
54 (if (eq 'description (second description-spec))
55 'description
56 (defining-description (second description-spec)))))
57 ,display-spec
58 ,object-spec &rest args)
59 (declare (ignorable args))
60 ,@(cdr tail))))))
61
62
63
64