Simple Menu Function

A while ago, I wrote a simple menu function that I use all the time:

DEF MENU(LIST$[])
 VAR CHOICE%,SCROLL%
 VAR BTN%=#UP
 
 REPEAT
  
  IF BTN% AND #UP+#DOWN THEN
   
   IF BTN% AND #UP THEN
    DEC CHOICE%
   ELSEIF BTN% AND #DOWN THEN
    INC CHOICE%
   ENDIF
   CHOICE%=MIN(MAX(CHOICE%,0),LEN(LIST$)-1)
   SCROLL%=MIN(MAX(SCROLL%,CHOICE%-29),CHOICE%)
   
   CLS
   VAR ROW%
   FOR ROW%=0 TO MIN(30,LEN(LIST$))-1
    LOCATE 1,ROW%
    PRINT LIST$[SCROLL%+ROW%];
   NEXT
   LOCATE 0,CHOICE%-SCROLL%
   PRINT "";
   
  ENDIF
  
  BTN%=BUTTON(1)
  VSYNC
  
 UNTIL BTN% AND #A
 
 CLS
 RETURN CHOICE%
END

Use the d-pad to move and A to select an item. The list scrolls if it's longer than 30 items. It can be used for a simple menu, file selection, etc. Example use:

DIM FILELIST$[0]
FILES "TXT",FILELIST$

VAR FILE$=FILELIST$[MENU(FILELIST$)]
FILE$[0]="" 'remove *
LOAD "PRG1:"+FILE$