Combining Multimeasure rests

[Urs Liska]

Hi all,

I'm trying to get the combination of consecutive MultiMeasureRests 
working but got stuck.

I have the function combineMMRests from
http://lilypond.1069038.n5.nabble.com/new-snippet-combine-multimeasure-rests-td144688.html

which works pretty well usually, but it doesn't merge rests when 
"something" is between them, even if that "something" is actually "nothing".

Consider the attached files.
Uncommenting one of the lines in the music expression causes either a 
\barNumberCheck or an empty music function to happen between the two 
rests, with the result of not merging them properly.

As far as I can see the problem is in the combinable-rest? predicate 
defined in the .ily file. I assume what I'd want is extending the list 
of cases where this predicate returns true by some more (currently the 
barnumber checks and empty music expressions returned by a function. Of 
course it may be that I'd find more cases in the future, but for now 
that would be it.

So I think my question is: is there a way to test if a list element is 
the result of an empty music function?

Thanks for any hints, explanations or improvements.
Urs

testMMRests.ly
Description: Text Data

combineMultimeasureRests.ily
Description: Text document