custom markup help

[Damian leGassick]

Hello list

I'm trying to get a markup to help with repetitive addition of scale-degrees 
with carats

I've got this far, but it's not picking up the new default baseline-skip value

\version "2.18.0" 


#(define-markup-command (sd layout props sdnum) (markup?)
  #:properties ((baseline-skip 0.5))
  "Put a number with a carat above the note."
  (interpret-markup layout props
    #{\markup \override #`(baseline-skip . ,baseline-skip)
              \column { \small {^ #sdnum }}    #}))


{g^\markup {\sd 3}}


any clues?

ideally i'd like to be able to write something like

{g^\sd{3}}

any assistance much appreciated

thanks as always

Damian