(element ,ly:music? "The single child of a Music_wrapper music object,
or the body of a repeat.")
(elements ,ly:music-list? "A list of elements for sequential of
simultaneous music, or the alternatives of repeated music.")
(elements-callback ,procedure? "Return a list of children, for use by
a sequential iterator. Takes a single music parameter.")
(element ,ly:music? "The single child of a Music_wrapper music object,
or the body of a repeat.")
(elements ,ly:music-list? "A list of elements for sequential of
simultaneous music, or the alternatives of repeated music.")
(elements-callback ,procedure? "Return a list of children, for use by
a sequential iterator. Takes a single music parameter.")