Bigstring = 'cattttccv'
NonDupeString = NonDupe(BigString)

* Result = 'catv'

Bigstring = 'cattttccv'
NonDupeString = NonDupe(BigString)
?NonDupeString

FUNCTION NonDupe(tcString)
LOCAL lcNewString, lnI, lnLen, lcChar
lcNewString = tcString
lnLen = LEN(tcString)
lnI = 1
DO WHILE lnI < lnLen
	lcChar = SUBSTR(lcNewString, lnI, 1)
	IF OCCURS(lcChar, lcNewString) > 0
		lcNewString = STRTRAN(lcNewString, lcChar, '', 2, -1, 2)
		lnLen = LEN(lcNewString)
	ENDIF 
	lnI = lnI + 1 
ENDDO 
RETURN lcNewString