Re: instrumentSwitch and addInstrumentDefinition use

[Keith OHara]

On Tue, 20 Jan 2015 08:51:13 -0800, Kieren MacMillan <address@hidden> wrote:

> 2. What would be required so that the \bar "||” \key \default stuff could be 
> avoided

It is awkward to make this happen with an add-on to current LilyPond.
Jan-Peter took the approach of watching for transposition changes in his 
autoTranspose engraver, to try generate key-change events in time for the 
Key_engraver to see, but I don't think this works yet.

If we can find the time to teach LilyPond to optionally print written pitches, 
given concert-pitch input without needing the explicit \transpose{} that we use 
now, we /could/ teach the Key_engraver to optionally generate the key-changes.  
(Then we will want a modifying option to omit the key-change, for traditional 
horn parts.)

> 3. In a perfect world, either \instrumentSwitch would take two music expressions
> (i.e., one for the “prep” period, one for the “playing” period), or there would 
> be
> an \instrumentPrep macro — primarily to deal with the markup activities (e.g.,
> “take clarinet”), but possibly for other things.

I would rather break free of the \instrumentSwitch structure, and define 
variables to do exactly what I want

prepClarinet {
   \set Staff.shortInstrumentName = \markup\concat {"B"\flat " Cl"}
   <>^\markup\italic { "muta in B"\flat } }

takeClarinet {
   \set Staff.printTransposition = bes
   \tag#'part {
      \once\set Staff.whichBar="||"
      \key\default
      <>^\markup\small\bold\concat { "Cl. in B"\flat } }}

and variables that can go in their own sequence separate from the notes, if you 
like
MarysArragement = {\key c\major s1*32 \prepClarinet  s1*4 \takeClarinet s1*32}
...
<<\MarysArrangement \reedIINotes >>