extending event-listener.ly

[luis jure]

hello list,

i have just discovered that you can save music events to a file with
event-listener.ly. this is an incredible feature for what i'm trying to
do, that is generate csound scores from lilypond files. i managed to do
that from the midi file generated by lilypond, using a very simple python
program. but much information is lost. using the text file generated by
event-listener would be much better, since i could manage dynamics and
articulations.

i'm only beginning to explore its possibilities, but one event i miss is
\parenthesize. the manual says:

"If some events that you want to see are not included, copy
‘event-listener.ly’ into your lilypond directory and modify the file so
that it outputs the information you want."

i looked at event-listener.ly, but i'm afraid it's way over my head. i can
hardly manage some basic python, for me scheme is undecipherable. 

could anyone give me a hint how to modify event-listener.ly to recognize
parenthesized notes?

any help would be greatly appreciated.

best,

lj