Re: [Pyobjc-dev] Auto bridging instances by conversion

[Just v. R. <ju...@le...>]

Bob Ippolito wrote:

> > Not converting can also be problematic: What if you pass the
> > NSString to an extension-function that expects a string (like
> > open), unless these get changed to also accept NSStrings you'll
> > have to perform manual conversion from NSString to a python string.
> 
> Say NSString acts like 100% like UserString (i.e. implements __str__
> and such), wouldn't PyArg_ParseTuple(AndKeywords) do The Right Thing?

I have no idea how well this can work, but UserString seems to be a
pain:

  Python 2.3a1 (#106, Feb  2 2003, 19:33:52) 
  [GCC 3.1 20020420 (prerelease)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import re
  >>> from UserString import UserString
  >>> s = UserString("lalalala")
  >>> s
  'lalalala'
  >>> repr(s)
  "'lalalala'"
  >>> open(s)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  TypeError: coercing to Unicode: need string or buffer, instance found
  >>> re.match("la", s)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
    File "/usr/local/lib/python2.3/sre.py", line 132, in match
      return _compile(pattern, flags).match(string)
  TypeError: expected string or buffer
  >>> 


Just