Seriously, read, reread and reread lilygut and CodingStyle, and
just start anywhere.
+Anywhere? Well, most of the comment doco are in the header files, so
+your best bet would be C<less lily/include/*.hh>. Some of the most
+important data-structures are to be found in:
+
+ - p-col.hh
+ - *request.hh
+ - register.hh
+ - score-elem.hh
+ - input-music.hh
+ - linespace.hh
+ - item.hh
+ - spanner.hh
+ - voice.hh
+
+
Q: Why GPL?
A: Yes.