How can I create conductor's annotations in Lilypond?

Question

I'm writing a second edition of a Legend of Zelda: Ocarina of Time medley I wrote and conducted in high school (it was indeed as fun as it sounds). Through our rehearsals, my director and I penciled in a bunch of changes that I somehow never got around to putting into the source code. Unfortunately, I lost all that code—it was before I'd begun my computer science studies and discovered git and make. However, this gives me the opportunity to do things over the right way.

My project structure is the same as the example given in section 5.5 of the Lilypond Usage manual. While some of the edits we made were applicable to the parts—articulations added or removed, etc.—some of them are meant purely for the conductor, such as reminders to cue sections of the orchestra. What's the best way to insert these? As far as I can tell, the .ly file containing the full score is nothing more than a series of \include directives, but that denies me the ability to add further information to a staff once it's included.

Answer 1

I guess a good, pure-Lilypond way would be using tags (see docs).

In short: you can annotate anything in your score with \tag #'whatever. An example could be

flutes = { \global
  \tag #'fullscore { c4-\markup\italic "wave hands at the flutes!" }
    \tag #'parts { c4 } d e f |
  g4 a b c' |
}

Then, you can use \keepWithTag or \removeWithTag. So, in the conductor's score, you would replace \new Staff \with { instrumentName = "Flutes" } { \flutes } with \new Staff \with { instrumentName = "Flutes" } { \keepWithTag #'fullscore \flutes }. That will keep only things tagged with #'fullscore and with nothing, and discard everything else, so you will get the "wave hands at the flutes!" markup.

Similarly you would use \removeWithTag #'fullscore (or \keepWithTag #'parts) in the parts to get rid of the markup.