Re: Implementation of music streams

[Han-Wen Nienhuys]

Erik Sandberg schreef:
> > > Here's my plan on how to front-port music streams to the 2.9 branch.
> > >
> > > 1. Implement classes Dispatcher, Stream_event, Listener (move modules
> > > from my thesis fork)
> > > 2. Add dispatchers event_source_, and possibly events_below_, to 
> > Context
> > > class.
> > > 3. Make Context::try_music send stream events to the event_source_.
>
> This step is now finished, patch attached. You can notice some

Can you also look my nits regarding warnings and SEND_EVENT_TO_CONTEXT 
below, and commit if "make web" still works?

> additional stuff that has been added as well, which currently is
> unused but will be used in future patches. You will notice that this
> patch makes lily spit out lots of Junking Event messages, which are
> harmless.

Can you make sure that in this patch those warnings are surpressed?
I don't want to leave lily in a state where it prints bazillions of 
messages.


Regarding SEND_EVENT_TO_CONTEXT(ctx, cl, ...)   and EVENT_PROPERTY:
I think the proper unproctect method nowadays is

  smob->unprotect()

also wouldn't it be possible to do away with EVENT_PROPERTY, and just do

  send_event_to_context (c, ev,
                         ly_symbol2scm ("key"), val,
                         ly_symbol2scm ("key2"), val2)

and in the macro do something like

  SCM args[] = { __VA_ARGS__ ,  0 };
  for (int i = 0; args[i]; i+=2)
      ..

I think that this reads more logically. Come to think of it, I don't see 
why SEND_EVENT_TO_CONTEXT should be a macro. Is there a reason why it 
can't be a function, except for the ly_symbol2scm() memoization?

If you want to keep the macro, then at least make sure the actual code 
body  which says

    Stream_event *_e_ = new Stream_event (ctx, ly_symbol2scm (cl));
    ctx->event_source ()->distribute (_e_);
    scm_gc_unprotect_object (_e_->self_scm ());      

is in a function. That makes debugging a bit easier and reads more 
logically.

--

Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen

LilyPond Software Design
 -- Code for Music Notation
http://www.lilypond-design.com