StrRepl:
Orig = ARG(1)
Oldtxt = ARG(2)
Newtxt = ARG(3)
Newstr = ''
Work = Orig
Do while POS(Oldtxt,Work) > 0
Newstr = Newstr||SUBSTR(Work,1,pos(Oldtxt,Work)-1)||Newtxt
Work= SUBSTR(Work,pos(Oldtxt,Work)+LENGTH(Oldtxt))
end
Newstr = Newstr||SUBSTR(Work,1)
return Newstr