I need to extract the Score part from a Lilypond file (example .ly file here) with separated voices.
My idea is to read the Lilypond grammar from a file and create a PHP parser using the PHP builtin features for parsers.
My question is how to read the Lilypond grammar?
I did not find a standard EBNF grammar source for Lilypond. And the Lilypond parser written in BIson on Github does not help much.