Re: [GLISS] facilitate changes of the (default-) drumStyleTable

[Marc Hohl]

Am 26.09.2012 02:25, schrieb Thomas Morley:
> Hi,
>
> sometimes I heard users complaining about the difficulty of changing
> the appearance of customized percussion staves,
>
> The NR "Custom percussion staves"
> states: "If you do not like any of the predefined lists you can define
> your own list at the top of your file." and demonstrates the use of
> \set DrumStaff.drumStyleTable = #(alist->hash-table <mydrums>)
> http://lilypond.org/doc/v2.17/Documentation/notation-big-page#custom-percussion-staves
>
> But if you only want to change _one_ value in the predefined lists you
> have no other chance than to follow the method mentioned above, i.e.
> _completely_ redefine the whole list.
>
> What do you think about providing a music-function, faciltating this, perhaps:
I like the idea of giving the user the ability to change only parts of 
the list
without having to rewrite the full list; I think that this concept could 
be of
use in other parts of lilypond as well, so perhaps it would be more 
general to
have something like

\changeTable 'drumStyleTable (...)

I'd like to avoid to have different commands with a different syntax; it 
makes
it harder for the user to remember ...

Oh, but a git grep "aslist->hash-table" shows that only 'drumStyleTable
seems to have a hash-table structure, so my proposal is probably useless.

+1

Marc
> %%%%%%%%%%%%%%%%%%%%%%
>
> \version "2.17.0"
>
> changeDrumStyleTable =
> #(define-music-function (parser location custom-style)(list?)
>    (make-music
>      'ApplyContext
>      'procedure
>      (lambda (x)
>       (let* ((ctx (ly:context-property-where-defined x 'drumStyleTable))
>              (dr-st-tab (ly:context-property ctx 'drumStyleTable)))
>       (if (list? (car custom-style))
>         (for-each (lambda (x) (hashq-set! dr-st-tab (car x) (cdr x)))
> custom-style)
>         (hashq-set! dr-st-tab (car custom-style) (cdr custom-style)))))))
>
> %--- Test
>
> customChanges =
> \with {
>          % changing single value:
>          \changeDrumStyleTable #'(lowtom () #t 30)
>          % changing a list of values:
>          \changeDrumStyleTable
>          #'(
>             (triangle doThin #f 16)
>             (bassdrum faThin #f -15)
>             (snare () #f 0)
>             )
> }
>
> \layout {
>          \context {
>                 \DrumStaff
>                 \customChanges
>         }
> }
>                 
>
> mus = \drummode {
>          bd4  sn  bd toml8 tri
>          bd ssh ss ssl  sna sn hh hh
>          hhc4 r sn tri
> }
>
> \new DrumStaff {
>          \mus
>          <<
>          \new DrumVoice { \voiceOne \mus }
>          \new DrumVoice { \voiceTwo \mus }
>          >>
> }
>
> %%%%%%%%%%%%%%%%%%%%%%
>
> -Harm
>
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