Re: Feature request: revert in another context

[David Kastrup]

Simon Albrecht <address@hidden> writes:

> On 28.11.2016 17:27, David Kastrup wrote:
>> Simon Albrecht <address@hidden> writes:
>>
>>> \version "2.19.49"
>>> %{
>>> It would be formidable if in such a case one wouldn’t need
>>> to look up the default stencil procedure, but could use either
>>> \undo or \revert.
>>> Is this a valid/sensible feature request?
>>> %}
>>> \score {
>>>    \new PianoStaff \with {
>>>      \omit SystemStartBrace
>>>      \accepts GrandStaff
>>>    } <<
>>>      \new GrandStaff \with {
>>>        % those don’t work
>>>        %\undo\omit SystemStartBrace
>>>        %\revert SystemStartBrace.stencil
>>>        % this does
>>>        \override SystemStartBrace.stencil =
>>> #ly:system-start-delimiter::print
>>>      } <<
>>>        \new Staff { 1 }
>>>        \new Staff { 1 }
>>>      >>
>>>      \new Staff { 1 }
>>>    >>
>>> }
>> The context modification for GrandStaff does not have access to the
>> unmodified definition of the enclosing PianoStaff (it doesn't even have
>> access to the unmodified definition of GrandStaff and does not know that
>> it will get applied to a GrandStaff) and even if it did, how should it
>> guess that you want to undo PianoStaff settings rather than Score
>> settings?
>
> OK, I’ll take that as a no. Or is it just that it would be complicated
> to implement a behaviour matching my naïve expectation?

It would be complicated to give a sensible definition of your naïve
expectation.

If you wrote

    \undo \omit GrandStaff.SystemStartBrace

or the equivalent

    \revert GrandStaff.SystemStartBrace.stencil

in the music itself, you could not expect it to revert the settings of
PianoStaff .  So why do you expect it do do this in the context mod ?


-- 
David Kastrup