Re: The exact semantics of the new \new command?

[Mats Bengtsson]

OK!

I noticed that this new syntax isn't yet described in
"9.1.1 Creating contexts" and is not listed in Cameron's
TODO list for the document updates. Unfortunately, I don't
have much time to contribute to the docs for the moment,
but this seems like something that easily could be updated.

  /Mats

Graham Percival wrote:

> On 23-Apr-06, at 2:50 AM, Mats Bengtsson wrote:
>
> > What, exactly, is the semantics of the \new <context> = <name> ...
> > syntax? As far as I understood the discussion leading to this
> > syntax, it should be equivalent to
> > \context <context> = <name>
> > if that context wasn't already created and it should
> > issue a warning if the context already existed.
>
>
> IIRC, it was decided that no warning would be issued.  This was to 
> make the implementation easier; I believe that there was some mention 
> of upcoming 3.0 syntax changes that would change \new and \context 
> further, and thus it didn't make sense to spend a lot of effort on it 
> right now.
>
> > As the following example shows (and the last example in
> > "More Stanzas", for example), what really happens is equivalent
> > to \new <context>, i.e. you get a new instance of the context
> > with some anonymous name. Also, no warning is issued.
> >
> > \version "2.8.0"
> >
> > \relative <<
> >  \new Staff = FIRST \new Voice { c1^"in FIRST" }
> >   % Should at least issue a warning:
> >  \new Staff = FIRST \new Voice { e1 e^"2nd incarnation of FIRST" }
> >  % Which of the above two will this one end up in?:
> >  \context Staff = FIRST \new Voice { g1 g g^"back in FIRST" }
> > >>
>
>
> Disregarding the warning issue (in HWN's words, "Don't Do That"), this 
> example works (if you rename the second FIRST to SECOND).
>
> > It seems that whoever updated the examples such as the
> > last example in "More Stanzas" rather had the impression
> > that
> > \new <context> = <name> ...
> > will always be equivalent to
> > \context <context> = <name> ...
> > which clearly isn't the case, so this is a problem both
> > in the implementation and the documentation and example
> > files.
>
>
> I didn't think that \new was the same as \context, but I also don't 
> claim to fully understand this issue.  As far as I know, right now 
> \new works well other than not giving warnings.
>
> The issue with "More Stanzas" is that I was updating the docs during a 
> music theory lecture, and (as always) I don't really know what I'm 
> doing with vocal music.  The two
> \new Lyrics = "mainlyrics"
> are obviously a mistake.  I've changed the second one to \context, and 
> it looks right to me.
>
> Cheers,
> - Graham


--
=============================================
        Mats Bengtsson
        Signal Processing
        Signals, Sensors and Systems
        Royal Institute of Technology
        SE-100 44  STOCKHOLM
        Sweden
        Phone: (+46) 8 790 8463                         
       Fax:   (+46) 8 790 7260
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