| 1 | (in-package :lisp-on-lines) |
| 2 | |
| 3 | (defvar *description*) |
| 4 | (defvar *display*) |
| 5 | (defvar *object* nil) |
| 6 | |
| 7 | |
| 8 | (deflayer display-layer) |
| 9 | |
| 10 | (define-layered-function display-using-description (description display object &rest args) |
| 11 | (:documentation |
| 12 | "Displays OBJECT via description using/in/with/on display")) |
| 13 | |
| 14 | (defun display (display object &rest args &key attributes ) |
| 15 | (let ((*display-attributes* attributes)) |
| 16 | (apply #'display-using-description (description-of object) display object args))) |
| 17 | |
| 18 | (define-layered-method display-using-description |
| 19 | :around (description display object &rest args) |
| 20 | (declare (ignorable args)) |
| 21 | (let ((*description* description) |
| 22 | (*display* display) |
| 23 | (*object* object)) |
| 24 | (contextl::funcall-with-special-initargs |
| 25 | (loop |
| 26 | :for (key val) :on args :by #'cddr |
| 27 | :collect (list (find key (description-attributes description) |
| 28 | :key #'attribute-keyword) |
| 29 | :value val)) |
| 30 | (lambda () |
| 31 | (contextl::funcall-with-special-initargs |
| 32 | (let ((attribute (find-attribute description 'active-attributes))) |
| 33 | (when attribute |
| 34 | (loop for spec in (attribute-value object attribute) |
| 35 | if (listp spec) |
| 36 | collect (cons (or |
| 37 | (find-attribute description (car spec)) |
| 38 | (error "No attribute matching ~A" (car spec))) |
| 39 | (cdr spec))))) |
| 40 | (lambda () |
| 41 | (call-next-method))))))) |
| 42 | |
| 43 | |
| 44 | |
| 45 | (defun display/d (&rest args) |
| 46 | (apply #'display-using-description args)) |
| 47 | |
| 48 | (define-layered-method display-using-description (description display object &rest args) |
| 49 | (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~% DESCRIPTION: ~A ~% DISPLAY: ~A ~% OBJECT: ~A ~% ARGS: ~S |
| 50 | |
| 51 | OMGWTF! If you didn't do this, it's a bug!" description display object args)) |
| 52 | |
| 53 | (defmacro define-display (&body body) |
| 54 | (loop with in-descriptionp = (eq (car body) :in-description) |
| 55 | with description = (if in-descriptionp (cadr body) 't) |
| 56 | for tail on (if in-descriptionp (cddr body) body) |
| 57 | until (listp (car tail)) |
| 58 | collect (car tail) into qualifiers |
| 59 | finally |
| 60 | (when (member :in-description qualifiers) |
| 61 | (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers.")) |
| 62 | (return |
| 63 | (destructuring-bind (description-spec &optional (display-spec (gensym)) (object-spec (gensym))) |
| 64 | (car tail) |
| 65 | `(define-layered-method |
| 66 | display-using-description |
| 67 | :in-layer ,(if (eq t description) |
| 68 | t |
| 69 | (defining-description description)) |
| 70 | ,@qualifiers |
| 71 | (,(if (listp description-spec) |
| 72 | (list (first description-spec) |
| 73 | (if (eq 'description (second description-spec)) |
| 74 | 'description |
| 75 | (defining-description (second description-spec))))) |
| 76 | ,display-spec |
| 77 | ,object-spec &rest args) |
| 78 | (declare (ignorable args)) |
| 79 | ,@(cdr tail)))))) |
| 80 | |
| 81 | |
| 82 | |
| 83 | |