Re: Tunable vs. internal properties

[Neil Puttock]

Hi Patrick,

2008/12/21 Patrick McCarty <address@hidden>:
> Hello,
>
> How are tunable and internal properties distinguished in the source
> code?  I am speaking of both context properties and grob properties.
>
> I can see that they are hardcoded in scm/define-context-properties.scm
> and scm/define-grob-properties.scm, but I am having trouble
> understanding how some properties are "tunable" but others are not.

> Can anyone point me to specific functions I should be looking for (in
> either C++ or Scheme)?

I think the only way is to pick a property, and based on how it's
defined in the relevant .scm file, look at the code to see how it's
used.

For example, we recently had a discussion about multi-measure rests,
where it's not possible to use breve rests for bars greater in length
than 4/2.  This behaviour is controlled in the engraver by setting the
property 'use-breve-rest, which the multi-measure-rest-interface reads
later when deciding what type of rest to print.  Since the property
setting takes place later than is possible using \override in a .ly
file, it's not user-serviceable, hence why it's classed as an internal
property.

Regards,
Neil