Re: Create \temporary for doing overrides without pop-first set (issue 6687044)

[dak]

On 2012/10/15 14:03:07, janek wrote:
> On Mon, Oct 15, 2012 at 2:51 PM,  <mailto:address@hidden> wrote:

> > Let's assume that we "unify" the interface to context and grob
> > properties.  The _default_ operation on a context property will
> > _always_ be overwrite rather than push, since context properties
track
> > the change of things like the current clef, the current key
signature,
> > the current whatever.  There is no point in keeping a stack for that
> > by default, and it would be seriously confusing.

> Hmm.  I've looked at available context properties, and in my opinion
> it could be useful to be able to perform "temporary \sets" on some of
> them:

> associatedVoice
> beamExceptions
> clefOctavation
> crescendoSpanner
> crescendoText
> fontSize
> instrumentName
> instrumentTransposition
> ottavation

Where would be the point to return to a previous ottavation rather
than just setting the desired one?

> PedalSustainStyle
> tupletSpannerDuration

Well, I did not claim that there was _no_ conceivable context property
where a temporary replacement would make sense and/or that we would
never want to implement a stack here.  The question was about the
_default_ behavior, and enough things are _tracked_ in their
_progress_ in context properties that a default stack behavior does
not make sense.

I have no idea what you are trying to argue here: of course, if
context and grob properties are supposed to be unified, _both_ will
_have_ a stack implementation if temporary changes in grob properties
are desired.

But that does not mean that the default mode of setting a property
should be pushing.

> [talk] also, i'd find it nice if it was possible to write
> \set Staff.color = #red
> and have LilyPond override #'color property for all grobs belonging to
> that Staff.  Currently doing this requires a music function, so it's
> out of reach for beginners.
> If we ever decided to do some "inheritance" of this sort, it would
> make even more sense to be able to set context properties temporarily.
> [/talk]

This is not really related to implementing \temporary.  It is more
related to
<URL:http://code.google.com/p/lilypond/issues/detail?id=2832#c3>.


http://codereview.appspot.com/6687044/