Proposing new arrow characters with Bidi_Mirrored=Yes

[Giacomo Catenazzi]

Also note:

https://www.w3.org/International/questions/qa-bidi-controls.en

BiDi may be done at higher level. So, maybe for simplicity sake, we 
should leave all but simple case to a different layer.

giacomo



On 2025-04-08 16:34, NeatNit via Unicode wrote:
> Hi, I hope this is the right place to bring this up. I could not find any discussions on this other than the document I quote.
>
> Quick intro: characters with the property Bidi_Mirrored=Yes will be visually mirrored within RTL text, such as Hebrew or Arabic. An easy example is the Greater Than symbol: A>B and א>ב.
>
> Arrow characters do not have this property: A→B but א→ב.
>
> I've found this discrepancy mentioned in this document:
>
> https://www.unicode.org/L2/L2022/22026r-non-bidi-mirroring.pdf
>
>> In particular, arrow and arrow-like characters
>> each often has a mirror character. One could
>> argue that they should have had the
>> Bidi_Mirrored=Yes property value, but they
>> don’t, and cannot now get that.
> Even if it weren't for Unicode's stability policies, there are two distinct usages of arrow symbols:
>
> To indicate directions, e.g. "Turn left (←) and then right (→)" - in this case the arrow refers to the physical direction and should not be mirrored in RTL. The existing arrow characters serve this purpose well: "פנה שמאלה (←) ואז ימינה (→)‏"
>
> As an operator: "Convert A->B and assign C<-D" - in this case the arrow direction should be mirrored if it appears in RTL text. Currently this can only be emulated with ASCII "->" as I've just demonstrated. Result: "המר א->ב וקבע ג<-ד".
>
> Therefore I think there should be new characters, "Forward Arrow" and "Backward Arrow", to serve the latter case. They would use the same glyphs as existing arrows, but have the Bidi_Mirrored=Yes property.
>
> Please let me know if this is likely to happen, and what I would have to do to make a proper proposal. And if any of you are convinced enough that you would like to make a proposal on my behalf, you are welcome to do so!
>
> The same reasoning can be applied to many other characters besides these basic arrows. At minimum, all arrow and arrow-like characters should be included. I haven't made a thorough search to find all affected characters, at least not yet.
>
> Note that some software, such as the Discourse forum software, convert "->" to "→" in user content, obviously unaware of this issue. These proposed bidi-mirrored arrow characters would be an appropriate replacement in such cases. Today, that simple search-and-replace must be replaced with parsing the text using the full Unicode Bidi algorithm to select the correct arrow, and even then some cases would be impossible to determine without knowing the base direction or more context which is not always available.
>
> Awaiting your comments.
>
> Thanks,
> Nitai
>
>