\version "2.14.0"

startSlashedGraceMusic =  {
  \override Stem  #'stroke-style = #"grace"
}

stopSlashedGraceMusic =  {
  \revert Stem #'stroke-style
}

slashedGrace =
#(def-grace-function startSlashedGraceMusic stopSlashedGraceMusic
   (_i "Create slashed graces (slashes through stems, but no slur) from
the following music expression"))



\relative c'' {
  c4 \slashedGrace e8 c4
}