CSUR Tonal

[Doug Ewell]

Luke Dashjr <luke at dashjr dot org> wrote:

>> As David pointed out, currency symbols really aren’t an analogy to
>> anything else. They are never built from combining characters, and
>> are never decomposable to them. This has nothing really to do with
>> TTS or pronunciation. One person in the Ubuntu thread mentioned that,
>> but that is not the primary reason.
>
> Why is that?

Why are currency symbols not decomposable to combining characters, or
equivalently, composable from them?

Well, I (rather famously) don't speak for UTC or WG2, and for all I
know, the official thinking on this has changed.

But the impression I got from 20 years following the Unicode Standard
was that a currency symbol such as $ is fundamentally different from a
capital S with a combining vertical line, even if that was the original
derivation of the symbol a few centuries ago.

Likewise, even if the euro sign € was designed as a stylized E with an
equals-sign overlay symbolizing equality, or something, that is no
longer its essential nature as a character.

By contrast, an A with an acute accent is, and will always be, an A with
an acute accent, regardless of whether it is encoded as a precomposed
character or as a combining sequence, or whether it is perceived as a
unitary letter in any language's orthography.

In particular with regard to the bitcoin hack^H^H^H^Hworkaround, U+20E6
COMBINING DOUBLE VERTICAL STROKE OVERLAY appears to have been encoded
for a specific math purpose, and not meant to be applied to just any
arbitrary base character on the basis of its appearance. (There was also
a corollary principle that characters should be used for what they are
meant to be, not just because the glyph "looks right.")

As I said, YMMV, and you are way better off checking with a real UTC or
WG2 member or even writing a proposal.

--
Doug Ewell | http://ewellic.org | Thornton, CO ����