6.7 Using Scheme code instead of \tweak

The main disadvantage of \tweak is its syntactical inflexibility. For example, the following produces a syntax error.

F = \tweak #'font-size #-3 -\flageolet

\relative c'' {
  c4^\F c4_\F

With other words, \tweak doesn’t behave like an articulation regarding the syntax; in particular, it can’t be attached with ^ and _.

Using Scheme, this problem can be circumvented. The route to the result is given in Adding articulation to notes (example), especially how to use \displayMusic as a helping guide.

F = #(let ((m (make-music 'ArticulationEvent
                          'articulation-type "flageolet")))
       (set! (ly:music-property m 'tweaks)
             (acons 'font-size -3
                    (ly:music-property m 'tweaks)))

\relative c'' {
  c4^\F c4_\F

Here, the tweaks properties of the flageolet object m (created with make-music) are extracted with ly:music-property, a new key-value pair to change the font size is prepended to the property list with the acons Scheme function, and the result is finally written back with set!. The last element of the let block is the return value, m itself.

Other languages: espaƱol.

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