From: Kenneth Whistler (firstname.lastname@example.org)
Date: Wed Feb 18 2004 - 20:29:06 EST
Michael responded to me:
> > >And the subscript / is over the edge, as far as I am concerned.
> > U+208D and U+208E aren't.
And David Starner continued:
> Why not? That's like saying that U+2128 ANGSTROM SIGN is
> justification for adding further canonically equivelent
> characters. U+208D and U+208E were, as I understood it,
> added soley because some terminal supported them as characters
> and Unicode wanted to support that terminal.
Actually, U+208D/U+208E were part of the original big
repertoire for Unicode 1.0, and their immediate justification
was the following two sources:
XCCS (Xerox Character Code Standard) 1980
375/331 Subscript opening parenthesis = Alternate rendition of
"opening parenthesis" (0/50)
375/332 Subscript closing parenthesis = Alternate rendition of
"closing parenthesis" (0/51)
IBM Corporate Specification circa 1988
GCGID SP062000 Left Parenthesis Subscript
GCGID SP072000 Right Parenthesis Subscript
It was known at the time that these were "hinky" characters in
the first place, but the likelihood of their existing in Xerox
and IBM data someplace (possibly for terminals, possibly for
something else) led to their inclusion in the original batch of
compatibility superscript and subscript characters, to enable
one-to-one mapping of existing data.
There have been very, very few additions of such characters since
that time, except for truly demonstrated linguistic modifier
letters, precisely because no one truly believes it to be the
right thing to keep extending these rendering hacks from the
1980's on a principled basis in the Unicode character encoding.
I stated in my last note:
> Every such precedent, based on
> whatever good or flimsy context it orginally got into the
> standard, has been used as a reason for encoding more such
> characters in the future, no matter how much they violate
> the ideals of the Unicode text model.
Michael just cited 208D/208E as justification for encoding
quod erat demonstrandum
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