Truncate filter

@register.filter
def trunc( string, number, dots='...'):
  """ 
  truncate the {string} to {number} characters
  print {dots} on the end if truncated

  usage: {{ "some text to be truncated"|trunc:6 }}
  results: some te...
  """
  if not isinstance(string, str): string = str(string)
  if len(string) <= number:
    return string
  return string[0:number]+dots