protected StringBuffer slice_to(StringBuffer s)
    {
	slice_check();
	int len = ket - bra;
	s.replace(0, s.length(), current.substring(bra, ket));
	return s;
    }
protected StringBuffer slice_to ( StringBuffer s ) { slice_check ( ) ; int len = ket - bra ; s . replace ( 0 , s . length ( ) , current . substring ( bra , ket ) ) ; return s ; }
/* Copy the slice into the supplied StringBuffer