RE: Tweaking in scheme

[Peter Gentry]

>-----Original Message-----
>From: Thomas Morley [mailto:address@hidden 
>Sent: Monday, June 29, 2015 12:10 PM
>To: Peter Gentry
>Cc: lilypond-user
>Subject: Re: Tweaking in scheme
>
>2015-06-29 12:54 GMT+02:00 Peter Gentry <address@hidden>:
>>
>> Tweaking in scheme
>>
>> The heart of the scheme procedure  I'm trying is
>>
>> #(define (instrumentrange music instrument )
>>    (  ly:music? string? )
>> ; extract the various portions of the music object (let ((es 
>> (ly:music-property music 'elements))
>>            (e   (ly:music-property music 'element))
>>            (p   (ly:music-property music 'pitch)));rebuild 
>the pitch and if a changed pitch add the color tweak
>> ...
>> ...
>>
>> (if (ly:pitch? p)
>>           (let ((new-pitch (naturalize-instrument-range p 
>instrument)))
>>           (ly:music-set-property! music 'pitch new-pitch)
>>           (if (and (not (equal? p new-pitch)) (color? my-color))
>>               (ly:music-set-property! music 'tweaks
>>               (acons
>>                 'color my-color
>>                (ly:music-property music 'tweaks))))))
>>
>>      music))
>>
>> This works fine and I have used \displayMusic to show the 
>music stream 
>> to investigate other possible properties that can be 
>specified in this way.
>>
>> I would like to specify note head style but this does not 
>seem to appear as a property that can be applied in the acons list.
>> In display music there is a complex list
>
>This is an \override
>
>> (make-music
>> 'ContextSpeccedMusic
>> 'contextt-type
>> 'Bottom
>> 'element
>> (make-music
>>  'OverrideProperty
>> 'pop-first
>> #t
>> 'grob-property-path
>> (list (quote style))
>> 'grob-value
>> 'harmonic
>> 'symbol
>> 'NoteHead))
>>
>> Can this in any way be implimented by  the 'tweaks method.
>
>
>
>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 }
>
>
>HTH,
>  Harm

Thankyou very musch that works a treat. 

I couldn't find any specific information in the manuals and the displayMusic 
output  contains a lot more than simply 'style and
'harmonic.