The rationale given for including mirrored half-stars as separate codepoints is right-to-left languages. I wondered why this was needed, since Unicode already h

The rationale given for including mirrored half-stars as separate codepoints is right-to-left languages. I wondered why this was needed, since Unicode already has the a right-to-left mark (RLM)[1]. I found the answer in a comment on "Explain XKCD".[2] The RLM usually only reorders characters, but does not mirror their glyphs. The exception are glyphs with the "Bidi_Mirrored=Yes" property, which are mapped to a mirrored codepoint.[3] The half-stars proposal includes a note on that property: "Existing stars are in the “Other Neutrals” class, so half stars should probably use the ON bidirectional class. The half stars have the obvious mirrored counterparts, so they can be Bidi mirrored. However, similar characters such as LEFT HALF BLACK CIRCLE are not marked as mirrored. I'll leave it up to the Unicode experts to determine if Bidi Mirrored would be appropriate or not." [1] https://en.wikipedia.org/wiki/Right-to-left_mark https://en.wikipedia.org/wiki/Right-to-left_mark [2] https://www.explainxkcd.com/wiki/index.php/1137:_RTL https://www.explainxkcd.com/wiki/index.php/1137:_RTL [3] http://www.unicode.org/Public/UNIDATA/BidiMirroring.txt http://www.unicode.org/Public/UNIDATA/BidiMirroring.txt