Re: "smart" transposition of key signatures

[Kieren MacMillan]

Hi David,

> What you can do if you want to is to write (cdr elts)
> instead of elts everywhere in the body of the cond.  If you do that, the
> key is not actually included in the resulting music.  You can then write
> 
> smartglobal = {
>  \smartkey c \minor { \key c \minor s1 }
>  \smartkey cis \major { \key cis \major s1 }
>  \smartkey es \minor { \key es \minor s1 }
> }
> 
> smartnotes = \relative c' {
>  \smartkey c \minor { c4 es g <c, es g> }
>  \smartkey cis \major { cis eis gis <cis, eis gis> }
>  \smartkey es \minor { es ges bes <es, ges bes> }
> }
> 
> this seems like a rather awkward interface prone to user error.

Agreed.  =(

> you don't get around telling every music how to enharmonize, and
> that won't happen if it is merely in parallel with some enharmonization 
> construct.

Understood — thanks for the clear explanation.
I was hoping there might be an [easy] way for a function to split parallel 
music into moments "in the same key" (i.e., split points defined by key 
changes), and then apply enharmonization to those chunks on a per-staff basis.

As I've said, this entire problem space — transposition with enharmonization — 
is of great interest to me, not only for "trivial" transpositions (like the 
type we've been discussing), but for the multiinstrumentalist situation (which 
crops up all the time in my musicals and operas, as well as many of my concert 
works for winds). If you have any ideas on how to solve all of that gracefully 
(i.e., with a non-awkward user interface), I'm all ear$.  =)

Thanks!
Kieren.