Private Use areas

Philippe Verdy via Unicode unicode at
Wed Aug 22 04:58:58 CDT 2018

May be this debate could find an end if there was a way to encode "private
use variants", so that we can override an existing character with correct
properties by creating a custom variant, which would immediately inherit
the properties of the base character on which it is encoded.

But for now there's no private use variant codes (PUV). I think that a
small block of 16 codes (may be even less) would be largely enough (given
that it would be used only in pairs after any standard character). They
could be used after any base character, possibly even after a combining
character (so the default combining class for these PUV should be 0).

For now there's still no way to have variant sequences unless they are
registered and standardized by Unicode but registration should be not
needed (forbidden) for sequences containing PUV.

I think there's a usage pattern for such schemes. Their default (spacing)
glyph could be a dotted circle with a single hex digit inside, it would be
itself non-joining, it would be itself bidi-neutral and used only after a
base character from which it would inherit the directionality (so the glyph
would appear automatically on the correct side). Actual fonts implementing
these PUV sequences would treat the PUV sequences as distinct unbreakable
entities  mapped to their own abstract character, and subject to common

Le mer. 22 août 2018 à 04:58, Andrew Cunningham via Unicode <
unicode at> a écrit :

> On Wednesday, 22 August 2018, Mark E. Shoulson via Unicode <
> unicode at> wrote:
>> On 08/21/2018 02:03 PM, Ken Whistler via Unicode wrote:
>> Best we can do is shout loudly at OpenType tables and hope to cram in
>> behavior (or at least appearance, which is more likely all we can get) that
>> vaguely resembles what we're after.  And that's not SO awful, given what
>> we're dealing with.
> At the moment I am looking at implementing three unencoded Arabic
> characters in  the PUA.
> For the foreseeable future OpenType is a non-starter, so I will look at
> implementing them in Graphite tables in a font.
> Andrew
> --
> Andrew Cunningham
> at
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