2.3.2 Music function usage

With regard to handling the argument list, music functions don’t differ from scheme functions, Scheme function usage.

A ‘music function’ has to return an expression matching the predicate ly:music?. This makes music function calls suitable as arguments of type ly:music? for another music function call.

When using a music function call in other contexts, the context may cause further semantic restrictions.

‘Polymorphic’ functions, like \tweak, can be applied to post-events, chord constituent and top level music expressions.

LilyPond — Extending v2.24.3 (stable-branch).