LilyPond

GNU LilyPond is the musical counterpart to TeX, a command-based note engraver.

A setup as own module "t-lilyfilter" can look like this:

\startmodule[lilyfilter]

\def\LILYTEMP{lilytemp} % subdirectory for LilyPond files

\def\ParseLilypondFile#1% #1 is the name of the output file
  {\ctxlua{thirddata.parselilypondfile("#1")}}

\startluacode
 thirddata = thirddata or {}

 -- create temp folder if missing
 if not lfs.isdir("\LILYTEMP") then
   lfs.mkdir("\LILYTEMP")
 end

 function thirddata.parselilypondfile(name)
   -- include all systems (pages)
   -- name is like \LILYTEMP/mainfile-temp-lilypond-21.pdf
   logs.report("LILYPOND","name='" .. name .. "'")
   local scname = string.gsub(name, '%.pdf$', '-systems.count')
   local syco = tonumber(io.loaddata(scname)) or 0


   for nr = 1, syco do
	 logs.report("LILYPOND","including system no." .. nr)
	 context("\\externalfigure[" .. string.gsub(name, '%.pdf$', '-' .. nr) .. "]")
   end
 end
\stopluacode

\usemodule[filter]
\defineexternalfilter[lilypond]
	[continue=yes,
            cache=yes,
	readcommand=\ParseLilypondFile,
	directory=\LILYTEMP/,
	output={\externalfilterbasefile.pdf},
	filtercommand={lilypond -dbackend=eps -ddelete-intermediate-files -o"\LILYTEMP/\externalfilterbasefile/" "\externalfilterinputfile"},]

% More possible options of LilyPond see lily.scm

\stopmodule

Beware, this works only with ConTeXt MkIV, since it uses Lua.

It includes single note lines (systems) to leave the page breaking to ConTeXt.

Tested with LilyPond 2.16 to 2.20

See also the LilyPond page in ConTeXt wiki.