Michael Kaplan invited me to give an actual scenario that requires private
use area support tags and an associated protocol. Well, the short answer is
that I am unable to find one at the present time with my present level of
knowledge.
I thought about how I might find such an actual scenario with the facilities
before me. I have access to as PC with Windows 95 which has Word 97 on it.
This enables one to create a Word document, select a font that contains
private use area characters, use Insert Symbol to add such a symbol or
symbols to the Word document, save the Word document then Save as HTML then
View HTML Source. From the HTML source code produced one can find the
decimal values of the codes. I tried the Junicode font and the Times New
Roman font, the latter because I remembered someone in this list writing
some months ago that the Microsoft Times New Roman font on their website
(which is the font that I am using, having obtained it so as to support on
this local machine the use of unicode in my 1456 object code system that is
on www.users.globalnet.co.uk/~ngo which is our family webspace in England)
has an extra character in it. Might this extra character, the one that says
OBJ in a dotted box, just possibly clash with the Junicode lady in the
Junicode font? An interesting situation is that the OBJ character came out
as  which is U+FFFC which is not in the private use area and I
learned some more about unicode by following that up in the unicode
specification (chapter 13 of version 3.0 under Specials, Replacement
Characters). I found that the dialogue box of the Insert Symbol facility in
Word 97 has near its top right corner a text box that will actually display
the text "Private Use Area" when the "selection cursor" for the symbol that
one is considering is on a symbol that is from the private use area. Does
what I have here termed the "selection cursor" have a proper Microsoft name?
I like to get the parlance of features of Microsoft products right. I now
notice that Arial also has the OBJ character, so perhaps OBJ is not the
additional character to which the poster from some months ago referred? I
also notice that both the Times New Roman and the Arial have fi and fl
ligatures twice, once under Private Use Area and once under Alphabetic
Presentation Forms. Junicode does not appear to have either fi or fl under
Private Use Area but does have ff, fi, fl, ffi and ffl under Alphabetic
Presentation Forms. The Junicode ffl placed in a Word document and then
formatted as Arial gives a black outline box. The Arial fi from the Private
Use Area placed in a Word document and then formatted as Junicode gave a
black outline box. The black outline box seems to represent "unknown to
this font". The use of the fi and fl from the Alphabetic Presentation Forms
section of Times New Roman, Arial and Junicode all carry through to the
other two fonts, regardless of which font one uses to insert the characters
in the first place.
The decimal codes for ff, fi, fl, ffi and ffl come out as 64256, 64257,
64258, 64259 and 64260 respectively, and these turn out to be U+FB00 through
to FB04 inclusive.
Michael continues:
If there is no such scenario, then why not involve your obviously fine
intellect in some of those real problems? In other words, help clear the
backlog of work rather than try to create work without proof that it is even
needed? Once we clear all of those things up, we will be bored and can
certainly move on to all of the theoretical matters that might be out there.
end quote
Well, as they say, I am grateful to the honourable gentleman for the remarks
in the first part of his question.
Two points arise. One is that I happen, as a user of unicode, to regard
what is to be done to support the use of the private use area as a real
problem. Secondly, are there any of the problems to which you refer where
there is an opportunity for people who do not represent the organizations
that are members of the Unicode Consortium to participate? I have not seen
any such opportunities advertised in the mailing list, though I have not
been a subscriber to the list for very long.
William Overington
1 May 2001
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