On 15/01/2014 16:28, Travis Griggs wrote:
........ of a sequence of graphemes I can use either a sequence of bytes or a
sequence of codepoints. They are both encodings of the graphemes; what unicode
says is an encoding doesn't define what encodings are ie mappings from some
source alphabet to a target alphabet.
But you’re talking about two levels of encoding. One runs on top of the other.
So insisting that you be able to call them all encodings, makes the term
pointless, because now it’s ambiguous as to what you’re referring to. Are you
referring to encoding in the sense of representing code points with bytes? Or
are you referring to what the unicode guys call “forms”?
For example, the NFC form of ‘ñ’ is ’\u00F1’. ‘nThe NFD form represents the
exact same grapheme, but is ‘\u006e\u0303’. You can call them encodings if you
want, but I echo Ned’s sentiment that you keep that to yourself.
Conventionally, they’re different forms, not different encodings. You can
encode either form with an encoding, e.g.
'\u00F1'.encode('utf8’)
'\u00F1'.encode('utf16’)
'\u006e\u0303'.encode('utf8’)
'\u006e\u0303'.encode('utf16')
I think about these as encodings, because that's what they are mathematically,
logically & practically. I can encode the target grapheme sequence as a sequence
of bytes using a particular 'unicode encoding' eg utf8 or a sequence of code points.
The fact that unicoders want to take over the meaning of encoding is not
relevant.
In my utf8 bash shell the python print() takes one encoding (python3 str) and
translates that to the stdout encoding which happens to be utf8 and passes that
to the shell which probably does a lot of work to render the result as graphical
symbols (or graphemes).
I'm not anti unicode, that's just an assignment of identity to some symbols.
Coding the values of the ids is a separate issue. It's my belief that we don't
need more than the byte level encoding to represent unicode. One of the claims
made for python3 unicode is that it somehow eliminates the problems associated
with other encodings eg utf8, but in fact they will remain until we force
printers/designers to stop using complicated multi-codepoint graphemes. I
suspect that won't happen.
--
Robin Becker
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