I just stumbled upon this: https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-23/#G13001
> Three pairs of deprecated format characters are encoded in this block: > > Symmetric swapping format characters used to control the glyphs that depict > characters such as “(” (The default state is activated.) > > [...] > > Symmetric Swapping. The symmetric swapping format characters are used in > conjunction with the class of left- and right-handed pairs of characters > (symmetric characters), such as parentheses. The characters thus affected are > listed in Section 4.7, Bidi Mirrored. They indicate whether the > interpretation of the term LEFT or RIGHT in the character names should be > interpreted as meaning opening or closing, respectively. They do not nest. > The default state of symmetric swapping may be set by a higher-level protocol > or standard, such as ISO 6429. In the absence of such a protocol, the default > state is activated. > > From the point of encountering U+206A INHIBIT SYMMETRIC SWAPPING format > character up to a subsequent U+206B ACTIVATE SYMMETRIC SWAPPING (if any), the > symmetric characters will be interpreted and rendered as left and right. > > From the point of encountering U+206B ACTIVATE SYMMETRIC SWAPPING format > character up to a subsequent U+206A INHIBIT SYMMETRIC SWAPPING (if any), the > symmetric characters will be interpreted and rendered as opening and closing. > This state (activated) is the default state in the absence of any symmetric > swapping code or a higher-level protocol. These deprecated format characters differ the ones proposed now in the following ways: - They only apply to characters that have the Bidi_Mirrored property, meaning they don't solve the use cases raised. - They apply to an entire span of text, whereas the proposed characters bind to a single preceding character each time. - It is ambiguous, at least to me, whether symmetric swapping should be inhibited or activated after U+206B ACTIVATE SYMMETRIC SWAPPING .. U+206A INHIBIT SYMMETRIC SWAPPING. The proposed characters would leave no ambiguity. As I mentioned, I will share a more complete description of the proposal in an email under a new title soon. If anyone would like to help draft it, contact me privately. Thanks, Nitai
