Re: Issue 4078: Doc: Use variables rather than instrument definitions (issue 138950043 by address@hidden)

[Keith OHara]

On Sun, 31 Aug 2014 00:14:11 -0700, <address@hidden> wrote:

> On 2014/08/31 06:58:47, Keith wrote:
>
> https://codereview.appspot.com/138950043/diff/1/Documentation/notation/vocal.itely#newcode2646
> > \set instrumentCueName = "Flute"
> > This is the *other* use of instrumentSwitch,
> > which I'll probably put back to a <>^\markup
>
> I think one of the points of the instrument switches was that you could
> do as many as you liked in a row (namely, attaching the instrument
> switch to the start of any music variable to be used for a particular
> instrument) without triggering extraneous switch messages.
>
> <>^\markup would seem to defeat that part of the original design.  While
> we don't need the instrumentSwitch command as such, the respective
> engravers weeding out duplication still serve a purpose.

This particular engraver seems to try, but fails, to suppress repeated 
identical settings.  (Maybe incorrect use of Scheme's eq? to compare the 
strings?)

{ \set instrumentCueName = "hautbois"
   c'4
   \set instrumentCueName = "hautbois"
   \set instrumentCueName = "cor.Ang."
   c'4
   \set instrumentCueName = "cor.Ang."
   c'4
   \set instrumentCueName = "cor.Ang."
   c'4 }

However, the (mis)use of instrumentCueName for labeling the instrument that is 
playing a cue (the topic of the documentation linked above) would not seem to 
benefit from suppression of repeated settings.  The use-case is something like

oboeNotes = \relative c'' {
   R1*32
   \new CueVoice { \set instrumentCueName = "flute" }
   \cueDuring #"flute" #UP { R1 }
   g2 c,
   R1*32
   \new CueVoice { \set instrumentCueName = "flute" }
   \cueDuring #"flute" #UP { R1 }
   g2 c, }