Inheritance/Single: Difference between revisions

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@@ Line 1,703: / Line 1,703: @@
 <lang txr>(defstruct animal nil
   name
-  (get-name
+  (:method get-name (me)
+    (if me.name me.name (error `get-name: animal @me has no name`)))
-    (lambda (me)
+  (:method speak (me stream)
-       (if me.name me.name (error `get-name: animal @me has no name`))))
+    (error "abstract animal cannot speak")))
-  (speak
-    (lambda (me stream)
-       (error "abstract animal cannot speak"))))
 (defstruct dog animal
+  (:method speak (me : (stream *stdout*))
-  (speak
-    (lambda (me : (stream *stdout*))
+    (put-line `@{me.(get-name)}: bark!` stream)))
-      (put-line `@{me.(get-name)}: bark!` stream))))
 (defstruct cat animal
-  (speak (lambda (me : (stream *stdout*))
+  (:method speak (me : (stream *stdout*))
-           (put-line `@{me.(get-name)}: meow!` stream))))
+    (put-line `@{me.(get-name)}: meow!` stream)))
 (defstruct lab dog)