How can I use custom macros with lilypond-book fragments?

Question

I am preparing a booklet using lilypond-book and have some snippets formatted with \begin{lilypond}[fragment]. These generally do what I want, but I would like to use some custom macros that I defined for chant formatting:

recitingNote = {
  \once \override NoteHead  #'stencil = #ly:text-interface::print
  \once \hide Stem
  \once \override NoteHead.text = \markup { \lower #0.5 \filled-box #'(0 . 6) #'(0 . 1) #0 }
  \once \override Dots.dot-count = #0
}

recitedText = {
  \once \override LyricText.self-alignment-X = #LEFT
}

I have these in a file named chant.lyinc, and in my usual full Lilypond documents I just \include "chant.lyinc" and am set. However, when I try it in fragment mode:

\begin{lilypond}[fragment]
  \include "chant.lyinc"
  c'2 d'2 e'2 f'2
\end{lilypond}

I get the errors

Parsing...
../chant.lyinc:1:1: error: not a note name: recitingNote

recitingNote = {
../chant.lyinc:1:14: error: syntax error, unexpected '='
recitingNote 
             = {
../chant.lyinc:8:1: error: not a note name: recitedText

recitedText = {
../chant.lyinc:8:13: error: syntax error, unexpected '='
recitedText 
            = {

Clearly the fragment wrapper is preventing the usual definitions from taking place. How can I use my custom includes with fragment snippets?

Answer 1

The lilypond-book processor works by extracting fragments and wrapping them in a boilerplate .ly file. After the "cut-&-pastable-section", it opens a new music expression with {, uses \sourcefileline 123 to provide debugging tracing, blindly pastes the contents of the fragment, and closes the expression with }.

A hacky workaround to use custom functions is to close the provided music expression with no contents, include the custom definitions, and open a new music expression. This generates warnings and probably screws up debug reporting and who knows what else, but it sort-of works:

\begin{lilypond}[fragment]
  } \include "chant.lyinc" {
  \recitingNote e'2 d'2 e'2 f'2
\end{lilypond}