Re: Concise term for non-ASCII Unicode characters

From: Sean Leonard <>
Date: Mon, 21 Sep 2015 01:22:14 -0700

First of all, thank you all for the responses thus far.

On 9/20/2015 5:51 PM, Martin J. Dürst wrote:
> Hello Sean,
> On 2015/09/20 23:48, Sean Leonard wrote:
>> What is the most concise term for characters or code points
> So we already have two different things we might need a term for.

> [...]
>> The terms "supplementary character" and "supplementary code point" are
>> defined in the Unicode standard, referring to characters or code points
>> above U+FFFF. I am looking for something like those, but for characters
>> or code points above U+007F.
> Anyway, what I wanted to show is that depending on what you need it
> for, there are so many different variations that it doesn't pay off to
> create specific short terms for all of them, and the term you use
> currently may be short enough.

Well what I am getting at is that when writing standards documents in
various SDOs (or any other computer science text, for that matter), it
is helpful to identify these characters/code points.

I think we can limit our inquiry to "characters" and "code points". Both
of those are well-defined in Unicode (see
<>). A [Unicode] code point is any value in
the range 0 - 0x10FFFF. A [Unicode] character is an abstract character
that is actually assigned a [Unicode] scalar value. Therefore the space
is Unicode code point > Unicode scalar value > Unicode character.

"supplementary" means outside the BMP, i.e., 0x10000 - 0x10FFFF.
"BMP" means inside the Basic Multilingual Plane, i.e., 0x0 - 0xFFFF.

The problem is that the BMP / supplementary distinction makes sense in a
UCS-2 / UTF-16 universe. But for much interchange these days, UTF-8 is
the way to go.

I wish that "non-ASCII characters" and "non-ASCII code points" (and
non-ASCII scalar values) were sufficient for me. Maybe they can be.
However, in contexts where ASCII is getting extended or supplemented
(e.g., in the DNS or in e-mail), one needs to be really clear that the
octets 0x80 - 0xFF are Unicode (specifically UTF-8, I suppose), and not
something else.

The expressions "beyond [...] ASCII" or "beyond the ASCII range" (as in,
characters beyond ASCII, code points beyond ASCII) have some support in
the Unicode Standard; see, e.g., Section 2.5 "ASCII Transparency"
paragraph. Additionally as Peter stated, an expression including "Basic
Latin block" (e.g., characters beyond the Basic Latin block) could work.

FWIW, the term "non-ASCII" is used in e-mail address
internationalization ("EAI") in the IETF; its opposite is "all-ASCII"
(or simply "ASCII"). (RFCs 6530, 6531, 6532). The term also appears in
RFC 2047 from November 1996 but there it has the more expansive meaning
(i.e., not limited or targeted to Unicode).

Received on Mon Sep 21 2015 - 03:23:03 CDT

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