Yes, overline characters are covered by Unicode. Here is a little test.
global const $dbar = ChrW(0x33F) ;DOUBLE OVERLINE
global const $bar = ChrW(0x305) ;OVERLINE
Func I_Quit()
Exit
EndFunc
Func To_Roman($iDec)
local $roman = ""
local $io[25][2] = [[1000000000,"M" & $dbar], _
[500000000,"D" & $dbar], _
[100000000,"C" & $dbar], _
[50000000,"L" & $dbar], _
[10000000,"X" & $dbar], _
[5000000,"V" & $dbar], _
[1000000,"M" & $bar], _
[500000,"D" & $bar], _
[100000,"C" & $bar], _
[50000,"L" & $bar], _
[10000,"X" & $bar], _
[5000,"V" & $bar], _
[1000,"M"], _
[900,"CM"], _
[500,"D"], _
[400,"CD"], _
[100,"C"], _
[90,"XC"], _
[50,"L"], _
[40,"XL"], _
[10,"X"], _
[9,"IX"], _
[5,"V"], _
[4,"IV"], _
[1,"I"]]
For $i = 0 To Ubound($io) - 1
While $iDec >= $io[$i][0]
$iDec -= $io[$i][0]
$roman &= $io[$i][1]
WEnd
Next
Return $roman
EndFunc
HotKeySet("{ESC}","I_Quit")
local $iNumber = 3457898377
SplashTextOn("Roman Numbers For:" & $iNumber,To_Roman($iNumber),@DesktopWidth,60,-1,-1,-1,default,24)
While True
wEnd