Re: About pitch

[Richard Shann]

On Tue, 2015-05-19 at 15:15 +0200, Ralf Mattes wrote:
>  Am Dienstag, 19. Mai 2015 10:12 CEST, PharoahS <address@hidden> schrieb: 
>  
> > Hi all
> > 
> > When i write #(display language-pitch-names) i get someting beginning wuth:
> > ((nederlands (ceses . #<Pitch ceses >) (ceh . #<Pitch ceh >)
> > 
> > i see in 
> > http://denemo.org/~rshann/gub.bak/target/mingw/root/usr/share/lilypond/current/scm/define-note-names.scm
> > <http://denemo.org/~rshann/gub.bak/target/mingw/root/usr/share/lilypond/current/scm/define-note-names.scm>
> >   
> > that it should begin with
> > (nederlands . (
> >                (ceses . ,(ly:make-pitch -1 0 DOUBLE-FLAT))
> >                (ceh . ,(ly:make-pitch -1 0 SEMI-FLAT))
> 
> This can't be true.
Well, besides quoting LilyPond source from a rather random place,
PharaohS failed to give the preceding context of the list which is in
the lilypond scm/define-note-names.scm as follows:

(define-public language-pitch-names
  `(

which has the backquote Ralf predicted.

>  You must be missing a backquote "`" somewhere since kommas "," 
> are only valid syntax within a "backquoted"  expression (schemers call that 
> quasi-quoted
> expression).
> 
> > Why is there such a difference? 
> 
> There is none, since the komma instructs the scheme reader to replace the 
> following
> expression with it's _value_ and the value of (ly:make-pitch ....) will be a 
> lilypond pitch
> which _prints_ like #<Pitch .....>.
> 
> > and how can i display from lily the
> > denemo-like version?
> 
> You can't.  The scheme 'display' function does display pitches the way it 
> does since
> there is no print representation for pitches that can be read back by scheme.
> Anything starting with "#<" is consiered "unreadable" by scheme. This is why 
> denemo
> needs to substitute pitches with scheme code to generate them.

I don't think this has anything to do with Denemo - what is being quoted
is a bit of LilyPond source code which is in the GUB directory used to
build the Denemo+LilyPond package for windows. (And it is only there
because the build has been run on that GUB directory which resulted in
the LilyPond sources being downloaded... this build gub.bak is anyway
ancient, the LilyPond sources may have moved on).

Richard



> NB: I think there _should_ be a readable scheme representation for pitches 
> .... but
> that's another thread ;-)
> 
>  HTH Ralf Mattes
> 
> > Thanks
> >  
> > 
> > 
> > 
> > --
> > View this message in context: 
> > http://lilypond.1069038.n5.nabble.com/About-pitch-tp176774.html
> > Sent from the User mailing list archive at Nabble.com.
> > 
> > _______________________________________________
> > lilypond-user mailing list
> > address@hidden
> > https://lists.gnu.org/mailman/listinfo/lilypond-user
>  
> 
> 
> 
> 
> 
> 
> _______________________________________________
> lilypond-user mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/lilypond-user