insert unique data in a list

[Fire Crow]

> Also, I'm not sure I like your abuse of the + operator to modify the
> object in place and return a flag. It is an API not shared by (as far as
> I can see) any other data type in Python.

I agree it couuld be more consisten with other object apis,

I also think that if every api has to conform to every other api
nothing will ever get done.

Heres a slightly more familiar version, it returns the value added or
none to conform with other APIs.

class unique_set(object):
   def __init__(self,list):
       self.list = list

   def __add___(self,val):
       if val not in self.list
          self.list.append(val)
          return val
       return None

>>> unique_list = unique_set(['a','b','c'])
>>> unique_list.list
['a', 'b', 'c']
>>> unique_list + 'd'
'd'

then a test opperand to verify if a value was inserted could be

if unique_list + 'd':
     # done some stuff

but it could also be used in cases like this

unique_added = unique_list + 'd' or 'not added'