⌂ Creating keyboard diagrams with chords or scales

For use in education a scheme function to display chords on a keyboard have been created.

The function is called 'keys' and it takes a list of note names as its argument. For example

\keys #'(c e g bes)

wil create a C7 chord

So far the following note names are accepted:

c, cis, des, d, ....., ais, bes, b, c', cis', des', ...., bes', b', c''

The function can be wrapped up in a markup command like this

cnine=\markup\keys #'(c e g bes d')

and be used like this

\relative c' { < c e g bes d' >^\cnine }