Sub-classing unicode: getting the unicode value

[Torsten Bronger]

Hallöchen!

I sub-classed unicode in an own class called "Excerpt", and now I
try to implement a __unicode__ method. In this method, I want to
get the actual value of the instance, i.e. the unicode string:

def __unicode__(self):
"""Returns the Unicode representation of Excerpt. Note that this is buffered,
so don't be afraid of calling it many times.

:Return:
- Unicode representation of ``self``

:rtype: unicode
"""
if not hasattr(self, "__unicode"):
self.__unicode = super(Excerpt, self).__unicode__()
return self.__unicode

Unfortunately, unicode objects don't have a __unicode__ method.
However, unicode(super(Excerpt, self)) is also forbidden because
super() allows attribute access only (why by the way?).

How does my object get its own value?

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus
Jabber ID: br*****@jabber.org
(See http://ime.webhop.org for further contact info.)

[Gabriel Genellina]

On 30 dic, 17:25, Torsten Bronger <[e-mail]>
wrote:

I sub-classed unicode in an own class called "Excerpt", and now I
try to implement a __unicode__ method. *In this method, I want to
get the actual value of the instance, i.e. the unicode string:

The "actual value of the instance", given that it inherits from
unicode, is... self.
Are you sure you *really* want to inherit from unicode? Don't you want
to store an unicode object as an instance attribute?

Unfortunately, unicode objects don't have a __unicode__ method.

Because it's not needed; unicode objects are already unicode objects,
and since they're immutable, there is no need to duplicate them. If it
existed, would always return self.

However, unicode(super(Excerpt, self)) is also forbidden because
super() allows attribute access only (why by the way?).

(because its purpose is to allow cooperative methods in a multiple
inheritance hierarchy)

How does my object get its own value?

"its own value" is the instance itself

--
Gabriel Genellina

[=?ISO-8859-1?Q?=22Martin_v=2E_L=F6wis=22?=]

How does my object get its own value?

def __unicode__(self):
return unicode(self)

Regards,
Martin

[Torsten Bronger]

Hallöchen!

Martin v. Löwis writes:

>How does my object get its own value?

def __unicode__(self):
return unicode(self)

I get an endless recursion with this.

I must admit, though, that I probably overestimate the costs
connected with unicode(my_excerpt) because Gabriel is probably right
that no real conversion takes place. A mere attribute lookup may
still be cheaper, but only very slightly.

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus
Jabber ID: br*****@jabber.org
(See http://ime.webhop.org for further contact info.)