Issue 1789 in lilypond: \tweak is 'broken' when trying to tie chorded notes (other than the first note in the chord)

[lilypond]

Status: New
Owner: ----
Labels: Type-Defect Priority-Low

New issue 1789 by address@hidden: \tweak is 'broken' when trying to tie  
chorded notes (other than the first note in the chord)
http://code.google.com/p/lilypond/issues/detail?id=1789

Here is the main thread:

--snip--


)-----Original Message-----
)From: address@hidden
)[mailto:address@hidden On )Behalf  
Of Jan Warchol
)Sent: 29 July 2011 08:11
)To: David Kastrup
)Cc: address@hidden
)Subject: Re: music function semantics
)
)David,
)
)2011/7/27 David Kastrup <address@hidden>:
)> Neil Puttock <address@hidden> writes:
)>
)>> On 26 July 2011 22:41, David Kastrup <address@hidden> wrote:
)>>
)>>> So the question basically is: which of those mechanisms is actually  
)>>> being in use?  Are there examples for existing music functions )>>>  
interpreting a postevent or a chord constituent?
)>>
)>> \tweak would be the most common usage for both of these cases:
)>>
)>> c1-\tweak #'color #red -\fermata
)>>
)>> and
)>>
)>> < \tweak #'color #red c>1
)>
)> So much for my "nobody needs that" theory.  The problem I have is that  
)> accepting \transpose in all the same places as \tweak does not seem )>  
like a good idea.
)>
)> On the other hand, whether an error gets thrown by the parser or by )>  
the expression builder might not make that much of a difference to the )>  
end user than it feels like making to me.

if i understood you correctly (it's about the difference in syntax between  
tweak and override?), i agree that it's quite a serious problem. ...ah, so  
it is possible to modify ties in a chord separately!  Do you realize that i  
didn't know about it?

--snip--

From Jan W

> Snippet for LSR?

I tried to write it, and do you know what?  It doesn't work!  Very stupid.

% if you apply this tweak to first note (c'), it works (tie gets weird).   
However, when applied to second note, it doesn't.
{ < c' ~   g'-\tweak #'control-points #'((1 . -1) (3 . 0.6) (12.5 .
0.6) (14.5 . -1)) ~ >   q }

--snip--

From David K

--snip--
If you take a look at the output of

\displayMusic { < c'-\tweak #'control-points #'((1 . -1) (3 . 0.6) (12.5 .
0.6) (14.5 . -1)) ~   g'-\tweak #'control-points #'((1 . -1) (3 . 0.6)  
(12.5 .
0.6) (14.5 . -1)) ~ >   q }

you'll see that it is not the fault of the parser.  The music expression  
still carries the respective information.

--snip--

From Reinhold

--snip--


Hehe. What David wanted to say: The parser correctly interprets the syntax  
and properly sets the control-points for the TieEvent. So, his part of  
current interest (the parser) works just fine.
However, there might be a bug later on when the graphical tie object is  
actually created from the music expression. There, the control-points seem  
to be handled differently for the two notes, even though both ties have the  
same value assigned...

> So is this a bug or something else? (I.e do we need a tracker item or
> not?) and can we tie individual notes within in a chord or not?

Yes, we can tie individual notes within a chord.
  <c~ e g~>4 <c e g c>
It's just the tweak that seems to be broken in your case... I would say  
this is a bug, although of low priority.