Re: Rebroadcasting events from a single timestep

[address@hidden]

On Jun 16, 2011, at 2:43 PM, Graham Percival wrote:

> On Thu, Jun 16, 2011 at 01:50:27PM +0200, address@hidden wrote:
>> If only it were that easy...
>> I have also tweaked the rest engraver to do automatic rest grouping.
>> 
>> For example, if in my file I have
>> \time 4/4
>> d4 r8. r8 r16 r8 r2 r4 r2
>> 
>> What will be printed is
>> d4 r4 r2 r1
> 
> That sounds like a job for a scheme music function.
> 

It is certainly doable in Scheme insofar as one can create engravers in Scheme. 
 However, in order to pull this off, I need access to context properties like 
measureLength and timeSignatureFraction, which are only available (as far as I 
know) from translators/engravers..  The type of filtering in the two snippets 
below deal with music before it gets sent to an engraver.

>> This is why the event needs to be rebroadcasted - it changes the rest to r1 
>> in the engraver (not in the .ly file).
>> I could, of course, implement a crude parser in python that combines my 
>> rests into a new input file, but this would be doubleplusunfun.
> 
> It still really sounds like you should use a combination of
> http://lsr.dsi.unimi.it/LSR/Item?id=372
> http://lsr.dsi.unimi.it/LSR/Item?id=122
> 
> 
>> Right now, I can make this work by deleting the multi-measure-rest engraver 
>> and copying all the code to rest-engraver.  However, I'd like to keep the 
>> changes as minimal as possible in hopes that the useful parts can remain 
>> separable and become part of LilyPond.
> 
> Scheme would be good for that.  Also, that way somebody else could
> compile your scores without needing to custom-patch the C++ in
> their source code.  Granted, you're probably never going to want
> anybody else in the world to compile this particular score... but
> you never know.  What if those teenagers wanted to play with
> stuff, and you gave them a short exerpt of this composition?  It
> would be *way* easier if they could just download 2.14.1 and
> compile the .ly in there, instead of trying to work with the
> source code.
> 

True, but even if I rewrote the rest engraver in Scheme, the question would 
still stand about rebroadcasting an event.
I think there may be enough users who are lazy about how they write their rests 
that it'd be valuable to have auto-rest-making à la auto-beaming, so I may wind 
up making a patch out of all this.

>> My question still stands for anyone who has any idea if/how stream events 
>> can be rerouted to other engravers.
> 
> Sure, but you should ask that on the -devel list, not the -user
> list.
> 

Generally I consult -user when it has to do with my composition activities, but 
you're right that the people one devel are those who wrote the whole 
translator/engraver/iterator system.  cc'ed to devel :)

Cheers,
MS