proposed Patch: \define-scheme-function

[David Kastrup]

The recent \contextStringTunings fixes were dissatisfactory to me
because I found the user interface awkward anyway.

Employing <URL:http://codereview.appspot.com/4969062>, one can code a
new command and the respective regtest as follows:

%% A scheme function for converting a chord to a string tuning
stringTuning =
#(define-scheme-function (parser location chord) (ly:music?)
  (let* ((ev-chord (car (extract-named-music chord 'EventChord))))
   (reverse (event-chord-pitches ev-chord))))

\header {

  texidoc = "For other tunings, it is sufficient to set
    @code{stringTunings}. The number of staff lines is adjusted
    accordingly."

}

\new TabStaff {
  \set TabStaff.stringTunings = \stringTuning <f' ais' dis'' gis''>

  \relative c''  { c4 d e f }
}


This is more obvious and nicer as either using #`(,(ly:make-pitch ...) ...)
(and, by the way, I have never seen such a strange tuning, so I consider
it likely that the respective arguments were simply wrong) or
contextStringTunings.

-- 
David Kastrup