Re: Defining event classes

[David Nalesnik]

Hi Nathan,

On Tue, Mar 31, 2015 at 3:53 PM, Nathan Ho <address@hidden> wrote:

On Mon, Mar 30, 2015 at 1:44 PM, Nathan Ho <address@hidden> wrote:

Hi list,

What is the most up-to-date way to define my own event classes?

I've looked at frameEngraver as a model but none of the old versions
seem to be working. The most up-to-date one I could find
(https://lists.gnu.org/archive/html/lilypond-user/2013-07/msg00373.html)
gives me numerous "Event class should be a list" errors and the frames
don't show up in the output, while this one
(https://lists.gnu.org/archive/html/lilypond-user/2013-07/msg00554.html)
spits out a few errors and segfaults. I'm using 2.19.17.

Not hugely surprised to see that didn't get a quick answer :)

With some trial and error and fumbling around I came up with the following code. Unlike the frame engraver code, this returns no errors or warnings, but the engraver doesn't seem to notice the BangEvent at all. If I change the listener to listen to music-event, then bang-trigger calls four times (once per note) seemingly ignoring the \bang. What's going on here?

If you're listening to 'music-event, you'll hear all sorts of events because it's the parent of many event-classes.  If you add an articulation to a note, for example, you'll hear that too.  Your invocation of define-event-class makes it the parent of bang-event.  

 

\version "2.19.17"

#(define-event-class 'bang-event 'music-event)

#(define bang-types

   '(

     (BangEvent

      . ((description . "BANG!")

         (types . (bang-event music-event))

         ))

     ))

You need to add 'event' to types for your event to register.  (I'd have to investigate why.)  Also, 'music-event' should be replaced with 'general-music'.

#(define bang-types

   '(

     (BangEvent

      . ((description . "BANG!")

         (types . (general-music event bang-event))

         ))

     ))

Hope this helps!

David