from django.utils.encoding import force_unicode
from django.utils.functional import allow_lazy


def truncate_letters(s, num):
    """ truncates a string to a number of letters, similar to truncate_words """
    s = force_unicode(s)
    length = int(num)
    if len(s) > length:
        s = s[:length]
        if not s.endswith('...'):
            s += '...'
    return s
truncate_letters = allow_lazy(truncate_letters, unicode)
