asmusf at ix.netcom.com
Sat Oct 29 16:56:20 CDT 2022
On 10/29/2022 1:31 PM, Gabriel Tellez via Unicode wrote:
> Looks like the real answer (hopefully) would be if we could find out
> what U+207B SUPERSCRIPT MINUS was originally added for.
These characters were in Unicode from very early on. Unlike some of the
later additions there is no link to a particular citation "in the wild".
Instead, the original repertoire collected a superset of then existing
character sets in reasonably wide usage. If any of their members
violated Unicode encoding principles, they were added as compatibility
characters (to facilitate round trip), otherwise as ordinary characters.
However, the question implicitly supposes that symbols and punctuation
are encoded by function. That is not generally correct. They are encoded
based on distinct (contrasting) shape compared to other symbols (noting
that for dashes and similar symbols, shape is not only defined by the
"ink" but also where that "ink" is placed). If a symbol was reused for
something else without a change in appearance, it would not therefore
qualify for being re-encoded.
In this case, the appearance of SUPERSCRIPT MINUS in a modern math font
shows a relative positioning to superscript digits, full sized digits
and relative length to the standard minus sign that matches to the TI
character for negation (within the constrained imposed by limited
resolution raster images).
I can see no indication that the TI engineers had some other symbol in
mind, that is had they had the choice of a Unicode-encoded outline font,
they would have chosen something with an appearance very distinct from
SUPERSCRIPT MINUS. Unless and until someone can come up with a very
cogent argument that they were really trying to model something that is
visually distinct from a superscript minus sign, there is no reason to
reject that mapping.
However, as I pointed out in another message, we should reject a mapping
to 203E even though some sources have it: the visuals simply do not match.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Unicode