1 (in-package :lisp-on-lines
)
7 (deflayer display-layer
)
9 (define-layered-function display-using-description
(description display object
&rest args
)
11 "Displays OBJECT via description using/in/with/on display"))
13 (defun display (display object
&rest args
&key attributes
)
14 (let ((*display-attributes
* attributes
))
15 (display-using-description (description-of object
) display object args
)))
17 (define-layered-method display-using-description
18 :around
(description display object
&rest args
)
19 (declare (ignorable args
))
20 (let ((*description
* description
)
25 (defun display/d
(&rest args
)
26 (apply #'display-using-description args
))
30 (define-layered-method display-using-description
(description display object
&rest args
)
31 (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~% DESCRIPTION: ~A ~% DISPLAY: ~A ~% OBJECT: ~A ~% ARGS: ~S
33 OMGWTF! If you didn't do this, it's a bug!" description display object args
))
37 (defmacro define-display
(&body body
)
38 (loop with in-descriptionp
= (eq (car body
) :in-description
)
39 with description
= (if in-descriptionp
(cadr body
) 't
)
40 for tail on
(if in-descriptionp
(cddr body
) body
)
41 until
(listp (car tail
))
42 collect
(car tail
) into qualifiers
44 (when (member :in-description qualifiers
)
45 (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
47 (destructuring-bind (description-spec &optional
(display-spec (gensym)) (object-spec (gensym)))
49 `(define-layered-method
50 display-using-description
51 :in-layer
,(if (eq t description
)
53 (defining-description description
))
55 (,(if (listp description-spec
)
56 (list (first description-spec
)
57 (if (eq 'description
(second description-spec
))
59 (defining-description (second description-spec
)))))
61 ,object-spec
&rest args
)
62 (declare (ignorable args
))