use variable out side procedure

[Freeman Gilmore]

\version "2.20.0"
#(use-modules (ice-9 regex)
j =  #(define-void-function
     (x)
     (string>?)
     (define Z x)
     (display Z))    %works
 \j "-3     +8  -6+1-8"

But how do i get Z (or x) out side so i can use the variable?  for example:
#(display Z)

Thank you, ƒg