Re: using "\transpose" with variables

[Mats Bengtsson]

Roland Goretzki wrote:
> Hello list, hello Tomas,
>
> You wrote:
>
>   
> > Hi,
> > I try to use \transpose with a variable as parameter like
> >
> > mykey = {d'}
> >
> > melody = \transpose c' \mykey 
> >          \relative c' {... }
> >
> > what??s wrong?
> >
> > I get the message: 
> > syntax error, unexpected STRING, expecting NOTENAME_PITCH or TONICNAME_PITCH
> >  melody = \transpose c' 
> >                         mykey
> >     
>
> Incorrect syntax.
> Have a look at the documentation at 6.1.8 Transpose:
>
>   \transpose c g' \mykey
>
> which means:
>
>   transpose from c to c' the music defined in \mykey
>
>   
Roland, I think you misunderstood the question. Tomas probably wants to
do the same transposition on a number of different scores and be able to
change the transposition of all of them, by only modifying a single line 
in the
.ly file, namely a definition of a variable that's used as the second 
argument of
\transpose. Unfortunately, the parser of LilyPond is hard-coded to only 
accept
an explicit pitch name. The solution is therefore to define your own 
music function
in Scheme, that is equivalent to \transpose but can handle a variable as 
the input.
See Chapter 12 "Interfaces for programmers" and in particular 12.3 "Building
complicated functions", for hints on how to do it.

  /Mats