in scheme."
}
-#(define-event-class 'scheme-text-span-event
- '(scheme-text-span-event
- span-event
- music-event
- StreamEvent))
+#(define-event-class 'scheme-text-span-event 'span-event)
#(define (add-grob-definition grob-name grob-entry)
(let* ((meta-entry (assoc-get 'meta grob-entry))
;; (class parent grandparent .. )
;; so that (eq? (cdr class) parent) holds.
-(define-public (define-event-class leaf heritage)
- (cond
- ((not (eq? leaf (car heritage)))
- (ly:warning (_ "All classes must be the last in their matrilineal line.")))
- ((not (equal? (cdr heritage)
- (list-head (hashq-ref ancestor-lookup (cadr heritage) '())
- (length (cdr heritage)))))
- (ly:warning (_ "All classes must have a well-defined pedigree in the existing class hierarchy.")))
- (else (hashq-set! ancestor-lookup
- leaf
- (cons leaf
- (hashq-ref ancestor-lookup
- (cadr heritage)
- '())))))
- *unspecified*)
+(define-public (define-event-class class parent)
+ "Defines a new event @code{class} derived from @code{parent}, a
+previously defined event class."
+ (let ((parentclass (ly:make-event-class parent)))
+ (cond
+ ((ly:make-event-class class)
+ (ly:error (_ "Cannot redefine event class `~S'") class))
+ ((not parentclass)
+ (ly:error (_ "Undefined parent event class `~S'" parentclass)))
+ (else
+ (hashq-set! ancestor-lookup
+ class
+ (cons class parentclass))))
+ *unspecified*))
;; TODO: Allow entering more complex classes, by taking unions.
(define-public (ly:make-event-class leaf)