\tweak-like function

[Werner LEMBERG]

Dear LilyPonders,


please consider this snippet.

  moveDyn =
    #(define-music-function (X Y) (number? number?)
      #{ \once \override DynamicLineSpanner.outside-staff-priority = ##f
         \once \override DynamicText.X-offset = #X
         \once \offset Y-offset #Y DynamicLineSpanner #})

  {
    g'2
    \moveDyn #-1 #5
    g'\f
  }

How can I convert `\moveDyn' to a \tweak-like function so that I can
say

  g'\moveDynTweak #-1 #5 -\f

instead?  I naïvely tried

  moveDynTweak =
    #(define-music-function (X Y) (number? number?)
      #{ \once \override DynamicLineSpanner.outside-staff-priority = ##f
         \once \override DynamicText.X-offset = #X
         \once \offset Y-offset #Y DynamicLineSpanner
         \etc #})

but this doesn't work.


    Werner