Martin v. Löwis wrote:
If the bytes are mapped to single half surrogate codes instead of the
normal pairs (low+high), then I can see that decoding could never be
ambiguous and encoding could produce the original bytes.

I was confused by Markus Kuhn's original UTF-8b specification. I have
now changed the PEP to avoid using PUA characters at all.

I find the PEP easier to understand now.

In detail I'd say that if a sequence of bytes >=0x80 is found which is
not valid UTF-8, then the first byte is mapped to a half surrogate and
then decoding is continued from the next byte.

The only drawback I can see is if the UTF-8 bytes actually decode to a
half surrogate. However, half surrogates should really only occur in
UTF-16 (as I understand it), so they shouldn't be encoded in UTF-8
anyway!

As for handling this case, you could either:

1. Raise an exception (which is what you're trying to avoid)

or:

2. Treat it as invalid UTF-8 and map the bytes to half surrogates
(encoding would produce the original bytes).

I'd prefer option 2.

Anyway, +1 from me.
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe: 
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com

Reply via email to