I’m not certain yet; although I’ve been writing all my own stuff in this language for months now, my actual implementation is mostly unfinished. (The only piece

I’m not certain yet; although I’ve been writing all my own stuff in this language for months now, my actual implementation is mostly unfinished. (The only piece that’s fully finished is list markers, which are based on CSS Counter Styles Level 3 plus parsing, so you can use e.g. cjk-decimal or bengali numbering in the source and it’ll retain that style in the output, correct values and all.) For this particular aspect, I’m still undecided on how best to actually implement it. The most likely approach is to hard-code rules (possibly in a couple of groups, e.g. “CJK” and “other”), with the ability to opt into or out of them as part of dialect configuration (which is a bit like how you can define custom roles or change the default role in reStructuredText, but more general, able to change more aspects of the language’s syntax—things like change *…* to be something other than italic, make ~…~ strikethrough, define new counter styles). You could also generalise some form of declarative line-break-collapsing rule like “if preceded and succeeded (after whitespace trimming) by a character with Unicode property East_Asian_Width ∈ {Fullwidth, Halfwidth, Wide}” or “if the preceding line matches /(?!< )—$/” or “if preceded by U+200B (ZWSP)” (this last example borrowing from https://www.w3.org/TR/css-text-3/#line-breaking https://www.w3.org/TR/css-text-3/#line-breaking, basically applying the formatting rules in reverse for parsing, similar to what I’m proposing with the em dash and doing with Counter Styles; when laying out, ZWSP introduces a line break opportunity without adding a space, so when parsing ZWSP and a line break, you clearly shouldn’t add a space). But unless I can be convinced of actual value in generalising it, giving just one or two switches is likely to be the most sensible implementation, for complexity (this will probably be an optional feature, incidentally), manageability and performance.