+ (message-handler #:init-value (wrap-apply actor-inheritable-message-handler)
+ ;; @@: There's no reason not to use #:class instead of
+ ;; #:each-subclass anywhere in this file, except for
+ ;; Guile bug #25211 (#:class is broken in Guile 2.2)
+ #:allocation #:each-subclass)
+
+ ;; This is the default, "simple" way to inherit and process messages.
+ (actions #:init-value '()
+ #:allocation #:each-subclass))
+
+(define (actor-inheritable-message-handler actor message)
+ (define action (message-action message))
+ (define (find-message-handler return)
+ (for-each (lambda (this-class)
+ (define actions
+ (or (and (class-slot-definition this-class 'actions)
+ (class-slot-ref this-class 'actions))
+ '()))
+ (for-each (match-lambda
+ ((action-name . method)
+ (when (eq? action-name action)
+ (return method))))
+ actions))
+ (class-precedence-list (class-of actor)))
+ (throw 'action-not-found
+ "No appropriate action handler found for actor"
+ #:action action
+ #:actor actor
+ #:message message))
+ (define method
+ (call/ec find-message-handler))
+ (apply method actor message (message-body message)))