Re: lilypond ChangeLog Documentation/user/examples....

[Han-Wen Nienhuys]

Erik Sandberg wrote:
> On Sunday 27 August 2006 17:41, Han-Wen Nienhuys wrote:
> > Graham Percival wrote:
> > > I'm sure that there's some reason why "\tempo x = y" is a horrible
> > > construct and must be replaced, but
> > >     \context {
> > >       \Score
> > >       tempoWholesPerMinute = #(ly:make-moment y x)
> > >       }
> > > looks unnecessarily complicated.  If that's the way it's going to be,
> > > I'll document it, but... why this?  Do we want to allow users to have
> > > different tempo in different Staff contexts?
> > we can hvae something like
> >
> >   #(set-tempo "4" 70)
> >
> > or maybe
> >
> >    tempo = #70
> >
> > \tempo has to go, because it is strange exception to the general syntax.
>
> How about
> \score {
>  { c d e }
>  \midi{ pre = \tempo 4. = 70 }
> }
> ?
>
> (I.e., \tempo is a music expression => it's not a grammatical exception)
>
> Semantics: If pre is set, then embed main input in a SequentialMusic when 
> interpreting music for midi. So instead of interpreting { c d e } above, we 
> interpret the expression:
> { \tempo 4.=70 { c d e } } 

This is a smart idea. Syntactically, I'm not a big fan of this (the 
double = is a little strange). However, it would be easy to encapsulate 
this with a Scheme expression,


  #(set-midi-tempo "4." 70)

however, we would need to have a separate music expression for each 
output block.

That would nicely match with a syntax change along the lines of


  \withoutput \layout { .. } {music expression}

  \withoutput \midi { .. } {music expression}

This implies that music functions are definitely allowed to have side 
effects, so it's a syntax change that has some serious repercussions.

ideas, comments?


--

Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen

LilyPond Software Design
 -- Code for Music Notation
http://www.lilypond-design.com