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2.1.6 Void functions
A music function must return a music expression, but sometimes we
may want to have a function that does not involve music (such as
turning off Point and Click). To do this, we return a void
music expression.
That is why the form that is returned is the
(make-music …)
. With the 'void
property
set to #t
, the parser is told to actually disregard this
returned music expression. Thus the important part of the void
music function is the processing done by the function, not the
music expression that is returned.
noPointAndClick = #(define-music-function (parser location) () (ly:set-option 'point-and-click #f) (make-music 'SequentialMusic 'void #t)) ... \noPointAndClick % disable point and click
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