I occasionally dally with XML in hobby code as a document source format, but I think what drives me away at the end is silly stuff with syntax, because it is a big spec well beyond the angle-bracket stuff, it wants to cover all the bases, do security right and do character encoding right - which means that "plain text editing" in it is some really unintuitive stuff where you can type in something like this paragraph and it might be parsed in a compatibility mode, but it won't be valid. As an interchange format or something loaded into application software tailored for it, it has more legs - and LLMs definitely wouldn't have any trouble making sense of it, which is good. A lot of yesteryear's challenges came from programmers short on time and eager to hack in features taking a heavily structured spec and wielding it like a blunt instrument. "XML? Sure, I can write a regex for that." Repeat that across three different programs and three different authors and you have a mess.
There is a format that I've hit upon that actually does get at what I want for myself, and that's BBCode. That's a great source format for a lot of stuff - still basically an angle-bracket, but with the right amount of structure and flexibility to serve as a general-purpose frontend syntax. Early implementations were "write a regex for that" but after decades of battle-testing, there are more graceful parsers around these days as well.
There is a format that I've hit upon that actually does get at what I want for myself, and that's BBCode. That's a great source format for a lot of stuff - still basically an angle-bracket, but with the right amount of structure and flexibility to serve as a general-purpose frontend syntax. Early implementations were "write a regex for that" but after decades of battle-testing, there are more graceful parsers around these days as well.