Re: dashed ties and line breaks

[David Nalesnik]

On Sun, Nov 4, 2012 at 1:46 PM, David Nalesnik <address@hidden> wrote:
> On Sun, Nov 4, 2012 at 8:37 AM, David Kastrup <address@hidden> wrote:
>> Thomas Morley <address@hidden> writes:
>>
>>>> Or, of course, the version as a tweak, not requiring you to specify "Tie":
>>>>
>>>> \version "2.17.6"
>>>>
>>>> \relative c'' {
>>>>   c1-\alterBroken dash-definition #'( ((0 1 0.4 0.75)) ((0 1 1 1)) )
>>>>      ~
>>>>   c1~
>>>>   \break
>>>>   c
>>>> }
>>>
>>> @ David (K)
>>> Sorry, but with this coding no dashed Tie is printed and the terminal 
>>> returns:
>>>
>>> warning: not a spanner
>>>
>>>      ~
>>
>> Oops.  Don't have the time to analyse this one right now, but I think
>> this is something that _should_ work.
>>
>
> The problem appears to be that 'span-direction is not set for tie events.
>
> At the moment I'm not sure what the best way is around the problem.
>

Well, if there isn't a more artful way...

alterBroken =
#(define-music-function (parser location property arg item)
  (symbol-list-or-symbol? list? symbol-list-or-music?)
    (if (ly:music? item)
        (if (or (eq? (ly:music-property item 'span-direction) START)
                (eq? (ly:music-property item 'name) 'TieEvent))
            #{ \tweak #property #(value-for-spanner-piece arg) #item #}
            (begin
              (ly:music-warning item (_ "not a spanner"))
              item))

[etc.]