RE: Question about U+FFFC

From: Paul Dempsey (Exchange) (paulde@exchange.microsoft.com)
Date: Mon May 24 1999 - 13:12:10 EDT


There is no Unicode-standardized notation or representation for the thing
that this character is replacing. It is standardized only as a placeholder
character. Everything else is up to the application or some other standard.
Unicode doesn't specify markup.

In general, I would not expect to see this in plain-text files. It is quite
useful in binary and in-memory formats.

For your example, I would not use ORC in the file at all. I'd use some other
notation along the lines of SGML or RTF. If I did want to use ORC in a file,
I would not use it as a paired delimiter as in your example. You really want
an open/close pair of characters for that style of markup. I would suggest
something more along the lines of \uFFFC<C:\MyImages\Image.GIF>

My application is real-world example of the use of OBJECT REPLACEMENT
CHARACTER (ORC). The ORC never appears in the persisted text in a file. At
run time, parts of our application synthesizes text that will be displayed
at certain points within the file. The ORC is inserted where the synthesized
text is to appear. When the display logic of our application sees ORC, it
calls back to another subsystem to fetch the synthesized text. This item
behaves as an atomic unit in the caret, editing, selection, and word wrap
logic because it _is_ just another character.

I hope this helps...

--- Paul Chase Dempsey
Microsoft Visual Studio Text Editor Development

-----Original Message-----
From: stephen_holmes@lionbridge.com
[mailto:stephen_holmes@lionbridge.com]
Sent: Monday, May 24, 1999 4:10 AM
To: Unicode List
Subject: Question about U+FFFC

Hi there,

This character is defined in the standard as OBJECT REPLACEMENT CHARACTER,
used
as I understand it, to facilitate the insertion of objects outside the scope
of
a normal Unicode text stream. Would someone have an example of how this is
used
(pseudo-code/algorithm)?

i.e., Should you delimit the inserted object with FFFC and how is the object
data typically represented in the stream? For example, I'd like to represent
an
inserted image file, would it look like

        \uFFFC C:\MyImages\Image.GIF \uFFCC

Any clarification would be greatly appreciated.

Thanks
Steve.

--------------------------------------
Stephen Holmes, Engineering Manager

Lionbridge Technologies, Grattan House
Temple Road, Blackrock.
Co. Dublin. IRELAND

Tel: +353-1-283-6050 x 118
Fax: +353-1-288-6220
Web: http://www.lionbridge.com
--------------------------------------



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