On Sun, 20 Jan 2013, Henning Hraban Ramm wrote:

> I'm using t-filter with LilyPond for my songbooklets like this:
>
> -----
>
> \def\readPDFfile#1{\externalfigure[#1]}
>
> \usemodule[filter]
> \defineexternalfilter[lilypond]
> 	[continue=yes,
> 	readcommand=\readPDFfile,
> 	directory=lilytemp/,
> 	output={\externalfilterbasefile.pdf},
> 	filtercommand={lilypond -dbackend=eps -dinclude-eps-fonts -dno-gs-load-fonts -o"lilytemp/\externalfilterbasefile" "\externalfilterinputfile"}]
>
> -----
>
> Now, I'd like my lilypond sections/buffers to have different names than just numbers; I'd prefer some unique IDs or even manually set names to be able to re-order them without the need of re-compiling.
> I.e. if I change the order of songs in my songbook, all LilyPond snippets must get recalculated, even if they didn’t change.

Does

\startlilypond[name=one]
....
\stoplilypond

what you are looking for? (see the docs for how this behaves behind the 
scenes)


> There are some more enhancements that I’d like to implement, e.g. 
> checking the resulting files if there are several pages or using single 
> notelines to let ConTeXt do the page breaking (like lilypond-book does 
> with LaTeX). I guess that would be as simple as replacing my 
> \readPDFfile with some Lua code - can you give me a hint how to do that?

See grph-inc.*. I'll post an example later on how to handle single page 
and multipage pdfs differently.

Aditya