    [NAME]
    ALL.dao.type.string.pattern.change

    [TITLE]
    string.change()

    [DESCRIPTION]

       1  string.change( pt :string, s :string, index=0, start=0, end=0 ) => int

    Replace the substrings that match to pt with string s, which may contain reference to
    captured subtrings for groups, for example, if s = 'abc%1', it means replacing with a
    string which is a concatenation of abc and the substring that match to the first group
    of pt.

    If index is positive, replace the index-th occurrence of the substring matching to pt.
    The substitution can also be restricted within a region starting from position start
    until position end.

    The number of occurrence of substitution is returned.