\version "2.19.32"

easyChArp = #(define-music-function (grow) (number?)
  ;% easy chord arpeggio; extendable in one staff without connectArpeggios
  #{ % apply in one voice, supplying growth parameter: + = up, - = down
    \once \override Arpeggio #'positions  = #(lambda (grob)
      (let ((iv (ly:arpeggio::calc-positions grob))
        (grow-hi (max 0 (/ grow 2)))
        (grow-lo (min 0 (/ grow 2))))
        (cons (+ (car iv) grow-lo) (+ (cdr iv) grow-hi))))
    $(make-music 'EventChord 'elements (list (make-music 'ArpeggioEvent)))
  #})

{
  \easyChArp #-6 \grace e''4  <g' f' d''>2 
}