On the lack of a SQUARE TB glyph

[Fred Brennan via Unicode]

On Friday, September 27, 2019 3:56:39 AM PST Ken Whistler wrote:
> On 9/26/2019 4:21 AM, Fred Brennan via Unicode wrote:
> > There is a clear demand for a SQUARE TB. In the font SMotoya Sinkai W55
> > W3,
> > which is ©2008 株式会社 モトヤ, the glyph is unencoded and accessed via the
> > Discretionary Ligatures (`dlig`) OpenType feature. It has name `T_B.dlig`.
> 
> Aye, there's the rub. Despite the subject of this thread, the problem is
> not the lack of a "glyph". This and many other particular squared forms
> may exist in Japanese fonts. The question then devolves to whether there
> is a *character* encoding issue here. What data representation and
> interchange issue is being raised here that requires an atomic character
> encoding, when the *presentation* issue can just be handled with
> OpenType features and already existing characters?

The purpose of Unicode is plaintext encoding, is it not? The square TB form is 
fundamentally no different than the square form of Reiwa, U+32FF ㋿, which was 
added in a hurry. The difference is that SQUARE TB's necessity and use is a 
slow thing which happened over years, not all of a sudden via one announcement 
of the Japanese government.

In plaintext SQUARE TB is fundamentally different than ASCII T followed by 
ASCII B. Plaintext tables (and programs generating them) and files already 
using SQUARE MB, SQUARE GB, etc benefit from SQUARE TB. 

> Note that there is a certain, systemic similarity here to the problem of
> extensibility of emoji, where encoding of multiple flags, of multiple
> skin tones, or of multiple gender representations, etc., is handled more
> generally by specifying how fonts need to map specified sequences into
> single glyphs, rather than by insisting that every meaningful
> combination end up encoded as an atomic character.

New emoji are still being encoded. The existence of SQUARE GB leads to its 
use, which then leads to people wanting SQUARE TB and resorting to hacks to 
get it done. If you didn't want people to request more square forms you 
shouldn't have encoded any at all. It's too late for that.

There is no sequence of glyphs that could be logically mapped, unless you're 
telling me to request that the sequence T <ZWNJ> B be recommended for general 
interchange as SQUARE TB? That's silly.

> --Ken