[I18n-sig] Re: [Python-Dev] Unicode debate

M.-A. Lemburg mal@lemburg.com
Tue, 02 May 2000 10:36:43 +0200


Just a small note on the subject of a character being atomic
which seems to have been forgotten by the discussing parties:

Unicode itself can be understood as multi-word character
encoding, just like UTF-8. The reason is that Unicode entities
can be combined to produce single display characters (e.g.
u"e"+u"\u0301" will print "" in a Unicode aware renderer).
Slicing such a combined Unicode string will have the same
effect as slicing UTF-8 data.

It seems that most Latin-1 proponents seem to have single
display characters in mind. While the same is true for
many Unicode entities, there are quite a few cases of
combining characters in Unicode 3.0 and the Unicode
nomarization algorithm uses these as basis for its
work.

So in the end the "UTF-8 doesn't slice" argument holds for
Unicode itself too, just as it also does for many Asian
multi-byte variable length character encodings,
image formats, audio formats, database formats, etc.

You can't really expect slicing to always "just work"
without some knowledge about the data you are slicing.

-- 
Marc-Andre Lemburg
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