Mike Ayers wrote:
I'd like to point out that I consider it a Good Thing not to have a
classification system. Should I choose to use PUA characters, I don't want
any application that I didn't write attempting to interpret their meaning,
since I may use them for anything (wasn't it you, William, who was working
on a soft processor which used PUA codepoints as instructions?) and I don't
want to waste time describing the usage for other applications (if the usage
can even be described).
end quote
In that case, should you choose to use PUA characters you may well not want
any application that you didn't write attempting to interpret their meaning.
So you need to
not let anyone who might try to have an application that you did not write
attempt to interpret their meaning get a physical copy of the file
and you need to
prohibit anyone whom you do allow to have a physical copy of the file from
trying to have an application that you did not write attempt to interpret
their meaning using your rights under intellectual property law.
If that is possible then so be it. In any case, if an application not
written by you did actually end up trying to read your file, then if you
were not using private use area support tags then it would not know how to
interpret the private use area codes that it encountered. For you, with
your declared choice, that would be fine. I am not suggesting that the use
of private use area support tags should be obligatory for people using
private use area codes in a plain unicode text file, I am only suggesting an
additional facility for users of unicode.
You need not waste time describing the usage for other applications as use
of private use area support tags would be an entirely optional facility for
people to use if they so wish and not use if they do not so wish.
Yes, it is me that is researching on a soft processor which uses PUA
codepoints as instructions. It is called a uniengine. The word uniengine
is generic with the meaning previously posted, so any set of codes that I
publish regarding a particular uniengine will need for the uniengine to have
a specific name, which I shall need to coin. I am thinking in terms of
licencing the technology and letting publishing the meanings of the codes so
that people know what the codes each mean. I would use private use area
support tags to assist the processor know when an in-line graphic was
encountered if I could.
Yet, the situation of a software application seeking to read in a file in
plain unicode text where that text contains one or more characters from the
private use area is going to be a widely practiced activity. How widely
practiced I do not know, but systems such as Word 97 have facilities to read
in plain text files and output plain text files. I suggest that future word
processing packages, from a variety of manufacturers, may well have a
selection box choice for plain unicode text for reading in files and plain
unicode text for writing out files.
When reading in a unicode plain text file, any encounter of a private use
code will need to be managed by the software, and even if the user operating
the computer knows that it is whatever, be it for example symbols for early
chemistry or symbols for ballet, then the computer system will need to know
as well. A font for early chemistry symbols may well not contain the
ordinary English alphabet within the font. So, once loaded as a file and
internally converted into the internal rich text format of the
wordprocessing software there may well be lots of work for the operator to
carry out changing the font of the private use area characters to early
chemistry symbols. Even if the word processor had a facility for a global
changing of the font of the private use area characters to the early
chemistry font, that facility would not be suitable if the document
contained even non-code-clashing uses of two private use area fonts. If
code clashing occurred, then the chances for ambiguity would be huge.
When writing out, private use area support codes could be added in to the
unicode plain text file produced, or not added in to the unicode plain text
file produced as the user chose from the choice presented in the drop down
menu of the selection box in the Save as .... section of the wordprocessor.
William Overington
2 May 2001
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