Remove unused event-type general-music

Remove unused event-type general-music

[david.nalesnik, 2015-04-01 14:43:55]

Please review.  Thanks!

[david.nalesnik, 2015-04-01 15:16:07]

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm
File scm/define-music-types.scm (right):

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm#ne...
scm/define-music-types.scm:343: (types . ())
Should Music be given a type? According to pattern, "music" with lowercase "m"?

[Trevor Daniels, 2015-04-04 15:25:27]

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm
File scm/define-music-types.scm (right):

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm#ne...
scm/define-music-types.scm:343: (types . ())
On 2015/04/01 15:16:07, david.nalesnik wrote:
> Should Music be given a type? According to pattern, "music" with lowercase
"m"?

Well, if "general-music" is unused presumably a type of "music" would also be
unused.  I'm rather outside my knowledge zone here, but is an entry of Music
required at all?  If "general-music" is being removed I'd have thought the Music
entry should be removed too.

Trevor

[david.nalesnik, 2015-04-04 16:17:20]

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm
File scm/define-music-types.scm (right):

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm#ne...
scm/define-music-types.scm:343: (types . ())
On 2015/04/04 15:25:27, Trevor Daniels wrote:
> On 2015/04/01 15:16:07, david.nalesnik wrote:
> > Should Music be given a type? According to pattern, "music" with lowercase
> "m"?
> 
> Well, if "general-music" is unused presumably a type of "music" would also be
> unused.  I'm rather outside my knowledge zone here, but is an entry of Music
> required at all?  If "general-music" is being removed I'd have thought the
Music
> entry should be removed too.
> 
> Trevor

Music is used.  For example, looking at what sort of object must be produced by
\shape:

#(display (car (ly:music-function-signature shape)))

==>

(#<primitive-procedure ly:music?> . #<Prob: Music C++: Music((void . #t))((name
. Music) (types general-music)) >
)

This patch would leave an empty entry for types.  That doesn't matter here --
The predicate ly:music? works just fine.  I just wonder if there would ever be
cause to recognize Music by its types, as for example, a engraver would
recognize NoteEvent by note-event.

[david.nalesnik, 2015-04-04 19:05:22]

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm
File scm/define-music-types.scm (right):

https://codereview.appspot.com/222090043/diff/1/scm/define-music-types.scm#ne...
scm/define-music-types.scm:343: (types . ())
On 2015/04/04 16:17:20, david.nalesnik wrote:

> > On 2015/04/01 15:16:07, david.nalesnik wrote:

> I just wonder if there would ever be
> cause to recognize Music by its types, as for example, a engraver would
> recognize NoteEvent by note-event.

Well, an engraver would be looking at stream events, so my "for example" doesn't
apply.

[dak, 2015-04-04 20:20:33]

On 2015/04/04 16:17:20, david.nalesnik wrote:

> Music is used.  For example, looking at what sort of object must be produced
by
> \shape:
> 
> #(display (car (ly:music-function-signature shape)))
> 
> ==>
> 
> (#<primitive-procedure ly:music?> . #<Prob: Music C++: Music((void .
#t))((name
> . Music) (types general-music)) >
> )
> 
> This patch would leave an empty entry for types.  That doesn't matter here --
> The predicate ly:music? works just fine.  I just wonder if there would ever be
> cause to recognize Music by its types, as for example, a engraver would
> recognize NoteEvent by note-event.

The usual way to recognize music types is by music-is-of-type? and the name is
not generally used except for subclassing.  Music would likely not be
interesting though.

[david.nalesnik, 2015-04-04 21:14:58]

On 2015/04/04 20:20:33, dak wrote:
> On 2015/04/04 16:17:20, david.nalesnik wrote:
> 
> > Music is used.  For example, looking at what sort of object must be produced
> by
> > \shape:
> > 
> > #(display (car (ly:music-function-signature shape)))
> > 
> > ==>
> > 
> > (#<primitive-procedure ly:music?> . #<Prob: Music C++: Music((void .
> #t))((name
> > . Music) (types general-music)) >
> > )
> > 
> > This patch would leave an empty entry for types.  That doesn't matter here
--
> > The predicate ly:music? works just fine.  I just wonder if there would ever
be
> > cause to recognize Music by its types, as for example, a engraver would
> > recognize NoteEvent by note-event.
> 
> The usual way to recognize music types is by music-is-of-type? and the name is
> not generally used except for subclassing.  Music would likely not be
> interesting though.

Of course "general-music" could be used to group music objects, too.  However,
from what I can gather, it is a remnant of times past when engravers accepted
Music objects by way of "general music" (instead of stream events) and figured
out what specific kind they were there.