As far as I understand, the following is what happens:
When you say something like:
\context { \Staff
\override TimeSignature #'style = #'numbered
}
it is equivalent to two steps, namely, 1) redefining the definition of
the identifier called \Staff, i.e.:
Staff = \context {
\Staff % = earlier definition of the identifier \Staff
\override TimeSignature #'style = #'numbered
}
and 2) using this definition, i.e.:
\context{
\Staff % Now with the new definition
}(The first step was introduced between 2.0 and 2.2)
What determines that the identifier is called \Staff and nothing else is that the default definition of the identifier \Staff contains a line: \name Staff This will also determine that the definition applies to Staff contexts and not to other contexts.
The \RemoveEmptyStaffContext is a bit special, since it provides an alternative definition of the Staff context type. For example, this means that also the \RemoveEmptyStaffContext identifier contains a line \name Staff
In analogy with what I wrote earlier, this means that
\context{\RemoveEmptyStaffContext} is equivalent to the following
two steps. 1) Making a new definition of the \Staff identifier:
Staff = \context{ \RemoveEmptyStaffContext }
and 2) using this definition:
\context{\Staff}Since the identifier \RemoveEmptyStaffContext is defined in ly/engraver-init.ly, its definition will not change when you redefine the \Staff identifier in you .ly file. If you think about it, you will realize that this "bug" is the only way to make it work.
/Mats
Graham Percival wrote:
Is this a bug, or an undocumented "feature"?
Lily 2.4.2, OSX. I have a global.ly, which contains \layout{ \context { \Staff \override TimeSignature #'style = #'numbered } }
In my actual piece, I use \include "../global.ly" \layout{ \context{ \RemoveEmptyStaffContext }}
(which presumably calls a \Staff context) The piece loses the 4/4 time signature.
So when you write \layout{ \context \Foo }} LilyPond takes the default values for the Foo context, rather than the current values. If this is deliberate, I'll document it. But if it's not hugely difficult to fix, I would call this a bug. :)
Not tested on 2.5.6, since we're still trying to build it. We're getting closer, though! :)
Cheers, - Graham
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-- ============================================= Mats Bengtsson Signal Processing Signals, Sensors and Systems Royal Institute of Technology SE-100 44 STOCKHOLM Sweden Phone: (+46) 8 790 8463 Fax: (+46) 8 790 7260 Email: [EMAIL PROTECTED] WWW: http://www.s3.kth.se/~mabe =============================================
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