Re: applyContext and music streams

[Han-Wen Nienhuys]

Erik Sandberg schreef:
> Hi,
>
> There are two different ways of handling applyContext for music streams:
> 1. The way I did it in my thesis: leave the command as it is, and just let the 
> apply-context-iterator apply the function.
> 2. Send the function in a stream event, and let a translator apply the 
> function (similar to how applyOutput is implemented).
>
> I like (1) better, because it makes the music stream format more 
> simple/verbose (it should always be possible to encode the the actions of an 
> applyContext as stream events, if they affect output).
>
> However, I realise that (1) will however break some code, such as 
> wilhelmus.ly, which currently set properties directly instead of using stream 
> events (if wilhelmus is exported to a music stream and then reloaded to a 
> different context tree, the property changes will be lost).


I think (1) is better too. Breaking wilhelmus.ly is a non-issue; we can 
adapt it if necessary. It should use the

  \override Foo #'space-alist #'staff-bar = #5

form anyway.

> BTW: My current progress is that all information now goes through the stream. 
> I propose that we add command-line flags --[no-]isolated-iteration, which 
> makes iteration and translation use separate context trees. This would be 
> slightly inefficient, but useful for testing/debugging, so it could be 
> defaulted to #t in development versions and to #f in stable ones.

I don't understand the issue. What do we gain by either solution?

--

Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen

LilyPond Software Design
 -- Code for Music Notation
http://www.lilypond-design.com