On Mon, 24 Aug 2015 11:00:32 +0100 (BST) William_J_G Overington <wjgo_10...@btinternet.com> wrote:
> Looking at the document > http://www.unicode.org/L2/L1999/99159.pdf > that has been mentioned, the four bracket characters are therein > described as follows. > 4X1F O LEFT BRACKET, REVERSE SOLIDUS TOP CORNER > 4X20 C RIGHT BRACKET, REVERSE SOLIDUS BOTTOM CORNER > 4X21 O LEFT BRACKET, SOLIDUS BOTTOM CORNER > 4X22 C RIGHT BRACKET, SOLIDUS TOP CORNER > So it looks like the pairings in Unicode today are as originally > intended. How so? There are two relevant pairings in Unicode - the Bidi_Mirroring_Glyph and Bidi_Paired_Bracket. Both pair the 1st and the 4th together and the 2nd and the 3rd together. Now, Bidi_Mirroring_Glyph is based mainly on appearance (or have I missed a caveat?), and that seems to be correct. Bid_Paired_Bracket is based on semantics, which are difficult to be sure of when we have no examples of use. Indeed, some quote marks are notoriously inconsistent from language to language. I am assuming that it is better to render reversed ⊄ U+2284 NOT A SUBSET OF (= <U+2282, U+0338 COMBINING LONG SOLIDUS OVERLAY) using an unreversed glyph for ⊃⃥ <U+2283 SUPERSET OF, U+20E5 COMBINING REVERSE SOLIDUS OVERLAY>, rather than the unreversed glyph of ⊅ U+2285 NOT A SUPERSET OF = <U+2283, U+0338>, despite U+2284 and U+2285 being a bidi-mirroring pair. If one took the view that a combining solidus didn't mirror (as indeed, it doesn't according to the UCD), and that the ticks are unhidden parts of solidi, then the Bidi_Mirroring_Glyph properties would be wrong! Good taste is probably the only way through the bidi mirroring maze. Richard.