If the length of the string exceeds the given limit, it will be cut
    off and three dots will be appended.

    @param s: the string to limit
    @type s: string
    @param length: maximum length
    @type length: non-negative integer
    @return: limited string, at most length+3 characters long

def strlimit (s, length=72):
    """If the length of the string exceeds the given limit, it will be cut
    off and three dots will be appended.

    @param s: the string to limit
    @type s: string
    @param length: maximum length
    @type length: non-negative integer
    @return: limited string, at most length+3 characters long
    """
    assert length >= 0, "length limit must be a non-negative integer"
    if not s or len(s) <= length:
        return s
    if length == 0:
        return ""
    return "%s..." % s[:length]