Edge cases largely don't matter, because again I'm not trying to make a book. I don't care if my table is off by a few pixels. 50% of the time I'm reading markdown it's not even formatted, it's just in raw format in an editor.
If you write Markdown in a way that your engine will misparse, you may well not notice—the compiler probably doesn’t even have the notion of throwing an error. The fact that you’re normally working with the unformatted text makes it even more likely that you won’t notice. (And the complexity is badly encapsulated, too.)
I have seen errors due to Markdown complexity so often. I just dealt with a blog where some images were completely missing because they’d written <img> tags in order to add some class attributes, and the engine didn’t allow raw HTML, and they didn’t notice they were gone (probably because ![]() images were still there). Markdown is so technically unsound it’s sometimes quite distressing.
We’re not talking about a table being off by a few pixels. We’re talking about words being mangled, text disappearing, much more severe stuff. Markdown isn’t even capable of table stuff.
HTML transformation is a bonus on top of that. If we want that we will mandate a specific Markdown engine with a strict parser.
If you only care about reading it raw, you don’t bother with Markdown. Some of what you write will be the same as Markdown, but not all—for example, no one would use its ridiculous link or image syntax.
The reason you write with Markdown syntax is because you want to be able to format it (even if you will normally consume it in plain text yourself). And once you’re using Markdown syntax, you need to know the rules, to a greater or lesser extent. You must be able to parse Markdown syntax mentally. If you don’t know the rules well enough, your mental parse will be incorrect, and you’ll produce errors. Errors that won’t be detected by your computer. That’s the hazard with Markdown compared to C++: your mental parser is buggy and incomplete, but with C++ the computer will generally catch your errors while with Markdown it will never catch your errors.
> Markdown is that it's easy to read, and its second-biggest advantage is that it's easy to write. How easy it is to parse doesn't matter
After saying MD is "easy to read" the meaning of "parsing" is clearly limited to automated parsing by non-humans, and the only reasonable reading is "provided the markup is easy to read for humans, the difficulty in constructing an automated parser is irrelevant".
When you write a file name a_b_c in one place, and a mathematical expression a*b*c in another place, and you don’t want to use `code formatting`, you need to know Markdown’s rules. Because otherwise, you’ll write a*b*c and get abc, instead of writing a\*b\*c to get a*b*c.
(And those are only the exact rules if you’re using CommonMark. On another engine, it might behave differently.)
If you only want to read, don’t use Markdown. But if you want to process as well, you need to know the processing.
Conveying meaning at the bitwise operator level is a different thing than applying emphasis to a few words in a sentence with bolding or embedding a hyperlink in a document.
Markup versus computer code is of course not exactly the same, but the nature of the mistakes—tokens in places they’re not supposed to be, and such—would generally lead to a syntax error in C++.
Good enough beats perfect.
> no one would use its ridiculous link or image syntax.
And many don't, which is fine! But some do, if they remember the syntax. Markdown is tolerant of that, and ultimately if the file is rendered to HTML Markdown engines know to just turn raw URLs into hyperlinks.
> The reason you write with Markdown syntax is because you want to be able to format it
Maybe sometimes. Not always. That's the point. A lot of the time it's nice that most technical people who write docs in text files all agree on what headings, lists, emphasis etc. should look like in plain text so we don't have to constantly do a dance of negotiating what the markup is. And the bonus on top of that is we can also get a reasonable HTML page out of it.
> If you don’t know the rules well enough, your mental parse will be incorrect, and you’ll produce errors. Errors that won’t be detected by your computer. That’s the hazard with Markdown
I mean, 'hazard'. Kind of an over-the-top way to put it. It's a text file for documentation purposes, not a production system handling money or something. Nobody cares if the Markdown has a few syntactic errors. The point is to convey information to other humans in a reasonably efficient way.
Really? I was under the impression that the fact that it is miserable to parse C++ directly means that it's also miserable to compile C++ - it can't be done quickly - which is something that everyone has to do all the time.
(And just to be completely clear, I'm not saying that the difficulty of parsing C++ makes it miserable to write a compiler. I'm saying that the difficulty of parsing C++ makes it miserable to run a compiler.)
How so? In Ada, Fortran, C, C++, Java, Python, etc. parsing is one of the many phases of compiling. Far from being orthogonal problems, parsing is a sub-problem of compiling.
YACC was called "Yet Another Compiler Compiler" because back in the day parsing was the bulk of compilation, now it's relatively minimal.
When we parse a string, we go up from low-level human-readable strings to intermediate parse trees to a high-level AST.
A process of compilation goes down from some kind of a high-level internal representation through phases to something that is close to the target low-level language.
It can go down from an AST, or LLVM-s internal representation, or whatever.
Problems solved by both processes are different:
1. Parsing is about finding string patterns (using regexps or PEGs or whatever) and representing these using a more strict high-level structure. The structure is usually tree-like but is also often a graph.
2. Compiling takes something high-level (a tree, a graph, etc) and emits something different, usually simplified.
A good example is a typical lisp implementation where the parser is trivial but compilation phases represent numerous simplifying phases.