erlend_sh If I asked you for a practical example it's because I'm not interested in arguing from a theorical perspective. It's a waste of time for all parties concerned. I'm looking for the practical impact of any decision.
I know a whole lot that support Markdown, e.g. GitHub, Reddit and StackOverflow
None of those sites implement the real Markdown, that's my point. For example, none of those sites support HTML, which is part of the original Markdown syntax. GitHub supports ~~strikethrough~~
and other extensions. There are many differences between the various librairies those sites used throughout the years and the original Markdown, but since they support the core and spirit of the original Markdown then from a practical standpoint they are all functionally equivalent.
I just tried creating a standard Markdown/Litedown link from wikipedia like this:
Yo check this out: (https://en.wikipedia.org/wiki/Taxonomy_(general)) Didn't even use markup. 😎
Balancing parentheses is easy, the plugin that autolinks URLs in regular text does it. That's why they're correctly balanced in the sentence above. That's in normal text though. Should they be balanced inside of markup too? Shouldn't markup be explicit? What happens if you wanted to link to the Wikipedia page for the left parenthesis or the right one? (test it online)
[(](https://en.wikipedia.org/wiki/()
[)](https://en.wikipedia.org/wiki/))
Markdown defines a way to escape special characters using a backslash. I think that's what should be used inside of markup. For some reason it doesn't work in Commonmark implementations. Not sure whether it's in the spec or an implementation bug. (test it online)
[taxonomy](https://en.wikipedia.org/wiki/Taxonomy_(general))
[taxonomy](https://en.wikipedia.org/wiki/Taxonomy_(general\))
(https://en.wikipedia.org/wiki/Taxonomy_(general))
My point is this: every implementation will have some differences. What matters is whether those differences affect regular users. If I see that regular users are having troubles posting links that contain a pair of parentheses then I'll definitely consider balancing them inside of markup without making it harder to post links with a single parenthesis. Everything is a trade-off and the benefits must outweigh the costs. (Edit: I looked into it and added support for one level of balanced parentheses)
CommonMark is a just another Markdown flavour. One that has codified the result of a hundred different edge cases. Are all of those edge cases worth the trouble? I don't know that they are. Talking about edge cases, what do you think the following should display?
*(*foo*)*
You can try it online. CommonMark emphasises the whole string and the "foo" part is double-emphasised. How can you create a string with emphasised parentheses and a non-emphasised "foo"? You'd have to use HTML for that. That's ok too. I don't think many users will try to post emphasised parentheses around non-emphasised text. It's ok if some edge cases are treated differently.