Partial compilation (was: Serious feedback and improvement headroom)

[Urs Liska]

Am 04.04.2014 15:04, schrieb Jan-Peter Voigt:
> > > What I would vote for very much is an option to recalculate the
> > > >>current system only, but with outputting the complete score anyway
> > > >>(however it may be determined what "current" is). This should work in
> > > >>many cases when a modification doesn't change line breaking. And it
> > > >>would dramatically increase the editing experience.
> > >
> > >There is little point in investing a lot of effort here when the current
> > >editing tools do not even deal with skipTypesetting and other things.
> > >
> > >Frescobaldi is the only LilyPond text editor that is actively developed.
> > >Denemo could probably make use of some of that technology, but as it has
> > >its own display engines, there is not a lot of pressure to get partial
> > >updates for it.
> But lilypond probably could assist a frontend with a map from musical
> flow to paper-flow. If the GUI knows that on page 3 are measures 27-42
> and the front end tracks an action, where I modified one slur-shape or
> one pitch, the front-end could trigger a compilation of measures 27-42
> and not the whole score.
> Its just an idea ...

Maybe that map wouldn't even be possible. I _assume_ that an editor 
might get that information by itself through point-and-click. But having 
the information directly would of course ease things.

What seems very useful to me would be something like this:

- compile a score similarly to using lilypond-book-preamble, i.e. in 
individual files per system.
- write out something like a LaTeX .aux file with information about 
measures in the systems. Editors can parse this file to know about the 
piece. An editor should then also be able to display these individual 
files like one score (maybe as a continuous page).
- Enable Lilypond to compile just a given system. This would probably 
work similar to skipTypesetting but with the difference that the system 
is laid out exactly as in the full context. Am I right that - once the 
line breaking has been done - a system is a quite independent entity for 
LilyPond?

That way an editor could provide a continuous view of the score and let 
LilyPond recompile any given system without having to redo everything else.
And it would be sufficiently straightforward to let LilyPond (or the 
editor) protest when the line breaking doesn't work anymore (e.g. the 
recompiled line gets longer and would need different line breaks).

For a "music entry mode" this could even be extended by a compilation 
mode that doesn't care at all about page breaking. Let the lines be 
ragged right and simply add measures until the line is full. This should 
reduce a noticeable part of the compilation time.

Urs
> ...
>
> Best, Jan-Peter