Internet Message Format Meeting Report
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d) Character set issues
The working group specified the definition of a character set for
the purposes of quad-x to be a unique mapping of a byte stream to
glyphs, a mapping which does not require external profiling
information.
1) The word "glyph" should be substituted by "character" to
follow ISO terminology.
The concept of "glyph" does only take graphic shape into
account and is related to _fonts_. The concept of "graphic
character" is based on several factors--semantics, shape,
origin, usage--and is used in _coded character sets_. It is
not uncommon that different glyphs represent the same
character, e.g. the different graphic forms of the AMPERSAND
character. On the other hand, the same glyph may in different
occurences represent different characters. The capital
Cyrillic character "A" for instance has exactly the same
shape as the capital Latin character "A".
Another point is that "characters" also include "control
characters", which definitely are not "glyphs".
the purposes of quad-x to be a unique mapping of a byte stream to
glyphs, a mapping which does not require external profiling
information.
2) The mapping is from a byte stream to a STREAM of characters.
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2) Mnemonic
A
lunch sub-group defined a profile for mnemonic, with a lead in
character of ``___'' and ASCII as the default character set.
3) Keld Simonsen has informed me that the actual decision of the
meeting was to use "&" (decimal code 38, hexadecimal 26) as
lead in character.
4) What is meant by saying that ASCII is the "default" character
set? Is it at all possible to use another coded character
set in connection with Mnemonic in quad-x? If not, it would
be better to talk about the "character set base" for Mnemonic
or something like that. (Since Mnemonic itself is regarded
as a character set, it may be confusing to talk about a
default _character set_ for Mnemonic.)