That's exactly my point, the solution you're discussing is about something else, and not relevant to what's discussed in this post.

The solution I describe merely serves for being an easier to parse way of nesting code blocks. I don't mean it to serve for any syntax highlighting, as I am understanding is your impression. That would only be an outcome for tools that act upon the AST generated by the parser. Tools that can take code of a programming language and color it. Not the job of a markdown parser, for which my idea is meant.

So if syntax highlighting isn't a problem. The standard way of presenting block of code in Markdown is to indent it.

Which is quick and easy to understand.