Re: [MathML 4] Add rules to map from non-combining to combining accents

Murray Sargent <murrays@exchange.microsoft.com> writes:

> Agreed. It's lamentable that holes in 1D400..1D7FF were
> put in where characters already existed in the Letterlike
> Symbols block (2100..214F), e.g., math italic ℎ is 210E,
> not 1D455. Industry math code uses the current definitions
> and filling in the holes would break that code or not be
> interchangeable. So we have to live with the encoding as
> is.

NO.  Old code does not need to be changed.   See below.

"MATHEMATICAL ITALIC SMALL H" is missing in Unicode.  The
sporadic U+210E is defined to be "PLANCK CONSTANT".  And
actually the Planck constant is quite commonly represented
by a glyph that does not match what good taste would dictate
for the missing U+1D455.

In fact, the standard as it is broken for non-visual
purposes.  How is a blind individual supposed to interpret a
sudden appearance of "PLANCK CONSTANT" in an article about
number theory.

It would cause breakage to change the definition of U+210E
but no breakage to add "MATHEMATICAL ITALIC SMALL H" as
U+1D455.

> Btw, I'm the UTC member who wrote the Unicode math
> alphanumeric proposals and I recommended against having
> the holes when the math alphanumerics were standardized
> (Unicode 3.1, March 2001). I was overruled on the basis of
> the principle that Unicode shouldn't have duplicate
> characters ☹.

That conclusion on which you were overruled is simply wrong.
The characters missing from the alphabets are not the same
characters as their sporadic look-alikes.  They may (or may
not) be represented with the same glyphs, but Unicode is
supposed to be a list of characters, not a list of glyphs.

Filling in the holes would not create duplicate characters.

Filling in the missing characters would not break anything.
I am absolutely not suggesting that the sporadic characters
in the neighborhood of U+2100 be changed.  None of those
character names match the character names that would fill in
the holes.

Thanks for listening.

                     -- Bill

Received on Tuesday, 6 November 2018 18:00:51 UTC