lemburg> This is not possible for unichr() in Python 2.x, since applications
lemburg> always expect len(unichr(x)) == 1

Oh, ok.

lemburg> Changing ord() would be possible in Python 2.x is easier, since
lemburg> this would only extend the range of returned values for UCS2
lemburg> builds.

ord() of Python3 (narrow build) rejects surrogate characters:

'\U00010000'
>>> len(chr(0x10000))
2
>>> ord(0x10000)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: ord() expected string of length 1, but int found

---

It looks that narrow builds with surrogates have some more problems...

Test with U+10000: "LINEAR B SYLLABLE B008 A", category: Letter, Other.

Correct result (Python 2.5, wide build):

   $ python
   Python 2.5.1 (r251:54863, Jul 31 2008, 23:17:40)
   >>> unichr(0x10000)
   u'\U00010000'
   >>> unichr(0x10000).isalpha()
   True

Error in Python3 (narrow build):

   marge$ ./python
   Python 3.1a0 (py3k:69105M, Feb  3 2009, 15:04:35)
   >>> chr(0x10000).isalpha()
   False
   >>> list(chr(0x10000))
   ['\ud800', '\udc00']
   >>> chr(0xd800).isalpha()
   False
   >>> chr(0xdc00).isalpha()
   False

Unicode ranges, all in the category "Other, Surrogate":
 - U+D800..U+DB7F: Non Private Use High Surrogate
 - U+DB80..U+DBFF: Private Use High Surrogate
 - U+DC00..U+DFFF: Low Surrogate" range