Chord library

[Sébastien Gross]

Hi there,

I am working on a guitar chord library for lily [1] based on the
\fret-diagram command.

The generator is written in python.

The chord configuration file is quite simple:

a section header indicates the chord type. Followin lines a defining a
chord name. If a chord name ends with "-b" the chord is considered a a
barred chord and would be expanded througth the whole neck.
If a chord has more than definition then a "-Two-" or "-Three-" ...
should be placed after the pitch name.

My explainations may be confusing (my english is not perfect :-/), so
this is an example:

[m]
# pitch                 6th     5th     4th     3rd     2nd     1st
#                       E       A       D       G       B       E
d               =       x       x       o       2-2     3-3     1-1
dis-b           =       x       x       1-1     3-3     4-4     2-2
d-Two           =       x       o       o       2-2     3-3     1-1
dis-Two-b       =       x       1-1     1-1     3-3     4-4     2-2

o = open string
x = muted string
x-y = fret-finger

Barre are autodetected

d => a classic Dm chord
d-Two => a variation of Dm including open A on the 5th string.
dis-b => the Dm chord played one fret higher to be expaned to the whole
neck
dis-Two-b => same as dis-b with the 5th string


the gen-chords.py script will generate chords commands like:

dm = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;6-x;5-x;4-o;3-2-2;2-3-3;1-1-1;" }
dmTwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;6-x;5-o;4-o;3-2-2;2-3-3;1-1-1;" }
dismITwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;c:5-4-1;6-x;5-1-1;4-1-1;3-3-3;2-4-4;1-2-2;" }
eesmITwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;c:5-4-1;6-x;5-1-1;4-1-1;3-3-3;2-4-4;1-2-2;" }
emIITwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;c:5-4-2;6-x;5-2-1;4-2-1;3-4-3;2-5-4;1-3-2;" }
fmIIITwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;c:5-4-3;6-x;5-3-1;4-3-1;3-5-3;2-6-4;1-4-2;" }
fismIVTwo = \markup{ \fret-diagram 
#"d:0.25;f:2;h:4;p:0.6;s:1;w:6;c:5-4-4;6-x;5-4-1;4-4-1;3-6-3;2-7-4;1-5-2;" }
[...]

fmIIITwo => A Fm chord played on the 3rd fret variation named "Two".

Then in an lilypond file you can use:
        ^\fmIIITwo
To call this chord.



a chord name is defined using this rule:

# M|m|sus(Two|Four)
#       M = Major chords
#       m = minor chords
#       sus = suspended chords (no 3rd)
#
# Additionnal tones:
#
# (no|add)?(d|M|A)(Eight) <- should not be used
# (no|add)?(d|m|M|A)(Two|Three|Six|Seven|Nine|Ten|Thirteen|Fourteen)
# (no|add)?(d|P|A)(Four|Five|Eleven|Twelve)
#
#       d = diminished
#       M = Major
#       P = Perfect
#       m = minor
#       A = Augmented


Thus:
[m] => minor
[MmSevenAFive] => 7/5#
[mmSevendFive] => m7b5
[susFourmSeven] => 7sus4
....


Currently not a lot of chord are defined and the generator is still
experimental. The aim of this library is to get a lot of predefined
chords out-of-the-box to prevent from redefining them in all files.


Comments are welcome.

Merry Xmas  & happy new year.



[1] - http://lilypond.chezwam.org/cgi-bin/darcsweb.cgi?r=Lilypond
    - http://lilypond.chezwam.org/darcs/lilypond/tools/chords-dict/

-- 
Sebastien Gross