       10 // PROC sample program
       20 //
       30 DIM a$(5), b$(5)
       40 a$:="String a"
       50 b$:="String b"
       60 aap(a$, b$)
       70 //
       80 FOR f:=1 TO 5 DO
       90   SYS assert, a$(f)="String a"
      100 ENDFOR f
      110 //
      120 FOR f:=1 TO 5 DO
      130   SYS assert, b$(f)="A$"
      140 ENDFOR f
      150 //
      160 PRINT "Ok"
      170 //
      180 PROC aap(b$(), REF a$())
      190   b$:="B$"
      200   a$:="A$"
      210 ENDPROC aap
