On 7/18/2018 6:43 AM, philip chastney via Unicode wrote:
there are also contexts where "Hello World!" can be read as the function "Hello", applied to the factorial value of "World" even though such a move wouldn't necessarily remove all ambiguity, the easiest solution is to declare that formal notations cannot be "plain" text
Of course they can -- and (usually) should be, as they are designed that way. To state otherwise would just create headaches for designing parsers for formal notations.
I think you are confusing ambiguity of *interpretation* of bits of formal notation, taken out of context, with ambiguity of *display* of formal notations in contexts where one does not know and control the paragraph directionality.
The easiest (and correct) solution, when displaying formal notation for visual interpretation by human readers, is to use tools where one knows and can rely on the paragraph directionality explicitly, so that Unicode bidi doesn't add an out-of-left-field set of display conundrums, as it were, for bidi edge cases that can result in *mis*interpretation by the reader.
In other words, if I am trying to read C program text or regex expressions, I expect that my tooling is not going to silently assume a RTL paragraph directional context and present me with visual garbage to interpret, forcing me to reverse engineer the bidi algorithm in my head, just to read the text. Why would I put up with that?
--Ken
