RE: [SPAM] Re: Tweaking in scheme

[Peter Gentry]

>-----Original Message-----
>From: David Kastrup [mailto:address@hidden 
>Sent: Monday, June 29, 2015 12:40 PM
>To: Thomas Morley
>Cc: Peter Gentry; lilypond-user
>Subject: [SPAM] Re: Tweaking in scheme
>
>Thomas Morley <address@hidden> writes:
>
>> How about:
>>
>> \version "2.19.21"
>>
>> %% regard output of:
>> \displayMusic
>> { \tweak style #'harmonic a'1 }
>>
>> tweakI =
>> #(define-music-function (parser location music)(ly:music?)
>>   (ly:music-set-property! music 'tweaks
>>     (acons 'style 'harmonic
>>       (acons 'color red
>>         (ly:music-property music 'tweaks))))
>>   music)
>>
>> { \tweakI a'1 }
>>
>> %% or:
>>
>> tweakII =
>> #(define-music-function (parser location music)(ly:music?)
>>   #{
>>     \tweak color #red
>>     \tweak style #'harmonic
>>     $music
>>   #})
>>
>> { \tweakII a'1 }
>
>As 2.19.22 is now available for download, let me smugly suggest:
>
>\version "2.19.22"
>tweakIII =
>#(define-music-function (music) (ly:music?)
>  (tweak 'color red
>    (tweak 'style 'harmonic music)))
>
>However, like all of the previous proposals, this relies on "music"
>being a single tweakable item.  For noteheads, there is the 
>more thorough style-note-heads function employed by 
>\harmonicNote, so this part could be done by (harmonicNote 
>music) instead (\harmonicNote uses a tweak for a single note 
>and override/revert for everything else).
>
>One can also try to do this kind of iteration oneself in order 
>to only use the less invasive tweaks and get the color covered:
>
>\version "2.19.22"
>tweakIV =
>#(define-music-function (music) (ly:music?)
>   (map-some-music
>     (lambda (m)
>       (and (music-is-of-type? 'note-event)
>            (tweak 'color red (tweak 'style 'harmonic m))))
>     music))
>
>If version 2.19.22 is not available, one can retain the 
>parser/location arguments and replace the (tweak ...) line by 
>the core of any of Harm's proposals.  map-some-music has been 
>available since 2.16.0 at least, and all the rest for longer.
>
>--
>David Kastrup

Thanks for that I have downloaded 2.19.22 for even more fun....