RE: Fret Diagram markup

[Heikki Johannes Junes]

IMHO, the \fret-diagram-verbose syntax is the direction to go. But the syntax,
which uses \fret-diagram-verbose should be optimized. Here is one, even less
verbose syntax than what is presented previously:

Some remarks of the possible syntax:
- number of ';' marks could give the number of strings,
- string numbers are not needed; strings may be given from left to right
- first number could give the fret position
- space may be used to separate multiple frets in one string
- a number attached with '-' mark could denote the fingering
- only notes on the same fret position (and also fingering!?) may have a slur
  (for example, vertical or diagonal slurs are not allowed), therefore, slur
  notation may be used

Then there could be some interface to the verbose syntax, what about:
- an empty 6-string \fret-diagram ";;;;;;"
- an empty 4-string \fret-diagram ";;;;"
- muted and open strings in a \fret-diagram "0;x;x;0;0;0;"
- fis major chord given in a simply filled \fret-diagram "2;2;4;4;4;2;"
- c major scale given in a multiply filled \fret-diagram ";3;0 2 3;0 2;0 1;;"
- fingered g major chord in a \fret-diagram "3-1;5-3;5-4;4-2;3-1;3-1;"
- slurred, fingered c major chord in a \fret-diagram "x;3-1-(;5-4;5-3;5-2;3-1-);

Other options may be given using some \override or similar before using
\fret-diagram.

There has been a request to be able to use an user-defined markup in a place of
a fret position, see
http://lists.gnu.org/archive/html/lilypond-devel/2004-02/msg00042.html
Syntax for such a FretChord context could be taken from TabStaff context, see
http://lilypond.org/doc/v2.3/Documentation/user/out-www/lilypond/Non-guitar-tablatures.html
I think that this extended feature could be an issue, not for the next, but
next-to-next major release. In general, it means just making a FretChord
context, which could be interpreted then for different purposes.

Greetings,

Heikki Junes