mop: In print-object-with-slots, use write for the slot values.

[lisp] / mdw-mop.lisp

diff --git a/mdw-mop.lisp b/mdw-mop.lisp
index e8946e8c8498b73dabf20855a7831fd1b8f569e8..e88ff1227a007e10fd375b154f3288b11d6960f9 100644 (file)
--- a/mdw-mop.lisp
+++ b/mdw-mop.lisp
@@ -27,12 +27,13 @@
 ;;; Packages.
 
 (defpackage #:mdw.mop
-  (:use #:common-lisp #+cmu #:pcl)
+  (:use #:common-lisp #:mdw.base #+cmu #:pcl)
   (:export #:compatible-class
           #:initargs-for-effective-slot #:make-effective-slot
           #:filtered-slot-class-mixin
             #:filtered-direct-slot-definition
             #:filtered-effective-slot-definition
+          #:predicate-class-mixin
           #:abstract-class-mixin #:instantiate-abstract-class
           #:mdw-class #:abstract-class
           #:print-object-with-slots))
@@ -151,7 +152,7 @@ (defmethod effective-slot-definition-class
       (call-next-method)))
 
 (defmethod initialize-instance :after
-    ((slot filtered-direct-slot-definition) &key &allow-other-keys)
+    ((slot filtered-direct-slot-definition) &key)
   (with-slots (filter) slot
     (when (and (consp filter)
               (or (eq (car filter) 'function)
@@ -172,9 +173,43 @@ (defmethod (setf slot-value-using-class)
      (class filtered-slot-class-mixin)
      (object standard-object)
      (slot filtered-effective-slot-definition))
-  (call-next-method (funcall (slot-definition-filter slot) object value)
+  (call-next-method (funcall (slot-definition-filter slot) value)
                    class object slot))
 
+;;;--------------------------------------------------------------------------
+;;; Predicates.
+
+(defclass predicate-class-mixin (compatible-class)
+  ((predicates :type list :initarg :predicate :initform nil
+              :documentation "Predicate generic function to create."))
+  (:documentation
+   "Class which can automatically generate a predicate generic function.
+    Adds the `:predicate' class option, which takes a single symbol argument
+    FUNC.  If specified, and non-nil, a generic function FUNC with one
+    argument will be defined (if it doesn't already exist) with a default
+    method returning nil, and a method added specialized on this class
+    returning a non-nil value."))
+
+(defmethod shared-initialize :after
+    ((class predicate-class-mixin) slot-names &key)
+  (declare (ignore slot-names))
+  (with-slots (predicates) class
+    (dolist (predicate predicates)
+      (let ((lambda-list '(thing)))
+       (let ((gf (if (fboundp predicate)
+                     (fdefinition predicate)
+                     (let ((gf (ensure-generic-function
+                                predicate :lambda-list lambda-list)))
+                       (add-method gf (make-instance
+                                       'standard-method
+                                       :specializers (list (find-class 't))
+                                       :lambda-list lambda-list
+                                       :function (constantly nil)))))))
+         (add-method gf (make-instance 'standard-method
+                                       :specializers (list class)
+                                       :lambda-list lambda-list
+                                       :function (constantly t))))))))
+
 ;;;--------------------------------------------------------------------------
 ;;; Abstract classes.
 
@@ -202,8 +237,14 @@ (defmethod make-instance ((class abstract-class-mixin) &rest whatever)
 ;;; Useful classes.
 
 (defclass mdw-class (filtered-slot-class-mixin
+                    predicate-class-mixin
                     compatible-class)
-  ())
+  ()
+  (:documentation
+   "A generally useful metaclass with handy features.  If I've done the
+    hacking right, there shouldn't be a significant cost to using this
+    metaclass for all your classes if you don't use any of its fancy
+    features."))
 
 (defclass abstract-class (mdw-class abstract-class-mixin) ())
 
@@ -233,7 +274,7 @@ (defun print-object-with-slots (obj stream)
                 (progn (format stream " ~@_~:I") (setf sep t)))
             (let ((name (pprint-pop))
                   (value (pprint-pop)))
-              (format stream "~S ~@_~:[~S~;<unbound>~*~]"
+              (format stream "~S ~@_~:[~W~;#<unbound>~*~]"
                       name (eq value magic) value))))))))
 
 ;;;----- That's all, folks --------------------------------------------------