Issue 514 in lilypond: abc2ly grace notes

[codesite-noreply]

Issue 514: abc2ly grace notes
http://code.google.com/p/lilypond/issues/detail?id=514

New issue report by gpermus:
A bug and a rendering problem in abc2ly (LilyPond) 2.11.34, probably easy
to fix:

* The option "abc2ly --beams=None" does not nest properly the "["'s it
writes in the output with respect to the command \grace{...}. For example,
the input
----
T:abc2ly grace note bug
M:C
L:1/8
Q:1/4=120
K:E Dorian
{ga}gdgb {a}g>d g<a|
----
will produce in the output .ly file:
...
\grace {    gis''8[    a''8  }   gis''8    dis''8
gis''8    b''8]
...

But it should be:
...
\grace {    gis''8[    a''8]  }   gis''8[    dis''8
gis''8    b''8]
...
That is, an extra "]" within the \grace{...}, and an extra "[", if called
for, on the note following.

* In addition, the written grace note values seem to be too long. ABC does
not leave any option to specify the written length of grace notes, so 
it is
up to the renderer for interpretation.

If I look into a folk music book, Robin Williamson, "Fiddle Tunes" (1976),
I think:

a. If there is only one note within the ABC grace note construct "{...}",
then one can use
\acciaccatura (as to produce a slurred note with a stroke on it).
b. If there are several notes within the ABC grace note construct "{...}",
the note values might be 1/4 (or at least 1/2) of the ABC default value (in
example above, the field "L:1/8"), and in addition, it seems me one can
write \acciaccatura instead of \grace.

I have tried to look for a semantic difference between grace notes using
slurs or not, and I have found none.

Below is how I think the "abc2ly --beams=None" output of the example above
might look like.

 Hans Aberg

----
\version "2.7.40"
\header {
   footnotes = ""
   tagline = "Lily was here 2.11.34 -- automatically converted from ABC"
   title = "abc2ly grace note bug"
}
voicedefault =  {
\set Score.defaultBarType = "empty"

    \override Staff.TimeSignature #'style = #'C
\time 4/4 \key e \major   \acciaccatura {    gis''32[    a''32]  }
gis''8[    dis''8
gis''8    b''8]  \acciaccatura {    a''8  }   gis''8.[    dis''16]    gis''16[
a''8.]  \bar "|"
}

\score{
   <<

   \context Staff="default"
   {
       \voicedefault
   }

   >>
   \layout {
   }
   \midi {
       \context {
        \Score tempoWholesPerMinute = #(ly:make-moment  120   4 )
        }
}
}



Issue attributes:
        Status: Accepted
        Owner: gpermus
        Labels: Type-Defect Priority-Postponed abc2ly

--
You received this message because you are listed in the owner
or CC fields of this issue, or because you starred this issue.
You may adjust your issue notification preferences at:
http://code.google.com/hosting/settings