Re: Issue 1274 in lilypond: convert-ly does not warn about #'dash-period = #-1 for LyricHyphen

[lilypond]

Updates:
	Labels: -Type-Scripts -Priority-Critical -Regression Type-Enhancement  
Priority-Medium

Comment #4 on issue 1274 by n.puttock: convert-ly does not warn about  
#'dash-period = #-1 for LyricHyphen
http://code.google.com/p/lilypond/issues/detail?id=1274

> But the IR says it should? ("3.1.57 LyricHyphen" -- 3.1.56 in the IR for  
> 2.12.3)

There's only one description for a property, but for convenience, several  
grobs may use the same property even if they use different code to handle  
the property's behaviour.  I agree it's confusing, but (AFAICT) there's  
never been any deliberate support for hiding hyphens using  
negative 'dash-period.

I see the behaviour in 2.12.3 isn't as strange as I originally thought:  
it's an arithmetical fluke based on the span points, which are wider due to  
the default position of the semibreve in the second bar.  In 2.13, Joe  
tweaked the code which sets the extra space in single-note bars, so the  
notes are closer.

Whether the hyphens appear or not with negative 'dash-period is a matter of  
luck dependent on the space calculated between hyphens.  The following  
snippets have no hyphens in 2.13.34:

\score {
  \relative c'' {
    c1 c8 c c c c c c c
  }
  \addlyrics {
    la -- la
  }
  \layout {
    \context {
      \Lyrics
      \override LyricHyphen #'dash-period = #-1
    }
  }
}

\score {
  \relative c'' {
    \override Score.NonMusicalPaperColumn #'full-measure-extra-space = #5
    c1 c1
  }
  \addlyrics {
    la -- la
  }
  \layout {
    ragged-right = ##f
    \context {
      \Lyrics
      \override LyricHyphen #'dash-period = #-1
    }
  }
}