paren =
#(define-event-function (dyn) (ly:event?)
   (make-dynamic-script
    #{ \markup \concat {
         \normal-text \italic \fontsize #2 (
	 \pad-x #0.2 #(ly:music-property dyn 'text)
	 \normal-text \italic \fontsize #2 )
       }
    #}))

\relative c'' {
  c4\paren\f c c \dynamicUp c\paren\p
}