Le 27/02/2021 à 02:16, Ken Ledeen a écrit :
I am struggling to understand the restrictions on substitution functions.
For example:
1) can a function include "\score { ...}" or can it only be invoked
INSIDE a \score?
2) is it possible to include \header { ...} inside a substitution
function? It fails when I try, but I don't understand why.
I assume I am missing some basic concepts regarding their use.
Thanks!
Hello,
Music functions must return music objects; \score blocks are not music
but general containers that enclose music as well as other objects such
as \header and \layout blocks.
However, replacing define-music-function with define-scheme-function,
you can define more versatile functions that are allowed to return any
kind of object for interpretation. For example:
\version "2.23.1"
failingFunction =
#(define-music-function () ()
#{
\score {
\header {
piece = "Piece A"
}
{ c' }
}
#})
% \failingFunction
succeedingFunction =
#(define-scheme-function () ()
#{
\score {
\header {
piece = "Piece B"
}
{ c' }
}
#})
\succeedingFunction
Hope that helps,
Jean
