On 5 Feb 2007 02:48:08 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> I want to have a str with custom methods, but I have this problem:
>
> class myStr(str):
> def hello(self):
> return 'hello '+self
>
> s=myStr('world')
> print s.hello() # prints 'hello world'
> s=s.upper()
> print s.hello() # expected to print 'hello WORLD', but s is no longer
> myStr, it's a regular str!
You could use the proxy pattern:
class GreeterString(object):
def __init__(self, str):
self.proxy = str
def hello(self):
return 'hello ' + self.proxy
def __getattr__(self, attr):
if attr in dir(self.proxy):
proxy_attr = getattr(self.proxy, attr)
if callable(proxy_attr):
def wrapper(*args, **kwargs):
return self.__class__(proxy_attr())
return wrapper
def __str__(self):
return self.proxy.__str__()
gs = GreeterString('world')
print gs.upper().hello()
Magic methods has to be overridden manually, I think.
--
mvh Björn
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