print RangeExpand$("-6,-3--1,3-5,7-11,14,15,17-20")

sub RangeExpand$(s$)
    local w$(1), n, i, r$, p, a, b

    n = token(s$, w$(), ",")

    for i = 1 to n
        p = instr(w$(i), "-", 2)
        if p then
            a = val(left$(w$(i), p-1))
            b = val(right$(w$(i), len(w$(i)) - p))
            repeat
                r$ = r$ + str$(a) + ","
                a = a + 1
            until(a > b)
        else
            r$ = r$ + w$(i) + ","
        end if
    next
    return left$(r$, len(r$) - 1)
end sub