I (mostly) lurk on the markdown discussion list, which is a great collection of people who implement and develop projects that use markdown. And there's been a recent spate of conversation about standardization of markdown implementations and syntax. This post is both a reflection on this topic and a brief overview of the oft-forgotten history.
Markdown is a simple project that takes the convention that most people have been using to convey text formatting and style in plain text email, and providing a very minimalist and lightweight script that translates this "markup" (i.e. "markdown") into HTML. It's a great idea, and having systems that make it possible for people to focus on writing rather than formating is a great thing.
People should never write XML, HTML, or XHTML by hand. Ever.
Here's the problem: the initial implementation is a Perl script that uses a bunch of pattern matching regular expressions (as you'd expect) to parse the input. It's slow, imprecise, there are a few minor logical bugs, there's no formal specification, and the description of the markdown language are ambiguous on a few key questions. Furthermore, there are a number of features that are simple, frequently requested/desired, with no official description of the behavior.
As people have gone about developing markdown implementations and extensions in other languages, to fix up the inconsistencies, to provide markdown support in every programming language under the sun, without a formal specification and disambiguation of the open question, the result is fragmentation: all the implementations are subtly different. Often you'll never notice, but if you use footnotes (which are non-standard,) or want to have nested lists, you will end up writing implementation-dependent markdown.
The result is that either you tie your text to a specific implementation, or you go blithely on with the knowledge that the markdown that you write or store today will require intervention of some sort in the future. If you need to extend markdown syntax, you can't without becoming an implementer of markdown itself.
That's an awful thing. And there's no real path out of this: the originator of markdown has publicly stated that he has no interest in blessing a successor, continuing development of the reference implementation, or in contributing to a specification process. Insofar as he controls the authoritative definition of markdown, the project to standardize markdown is dead before it even begins.
The problem is that while most people involved (implementers, application developers, etc.) in markdown want some resolution to this problem: it's bad for users and it makes implementing markdown difficult (which markdown flavor should you use? should you reimplemented bugs for consistency and compatibility, or provide a correct system that breaks compatibility?) At the same time, markdown implementations are not commercial products and were built to address their author's needs, and none of those maintainers really have the time or a non-goodwill interest in a standardization process.
If markdown standardization weren't doomed from the start, the fact that the only people with any real ability to rally community support for a standardized markdown, are not inclined to participate in a standardization process.
If markdown were better, more clear, and more rigorously defined and implemented, this wouldn't be a problem, but the truth is that markdown's main role has been for README files, blog posts, wikis, and comments on blog posts and in discussion forms.
It's a great "lowest common denominator" for multi-authored text that needs rich hypertext features but needs markdowns simplicity and intuitiveness. Big projects? Multi-file projects? Outputs beyond single files?
Sure you can hack it with things like maruku and multi-markdown to get LaTeX output, and footnotes, and more complex metadata. And there are some systems that make it possible to handle projects beyond the scope of a single file, but they're not amazing, or particularly innovative, particularly at scale.
To recap, markdown is probably not an ideal archival format for important text, because:
The implementation-dependency means that markdown often fails at genericism, which I think is supposed to be it's primary features.
Generic text representation formats are a must.
If you need output formats beyond HTML/XHTML then markdown is probably not for you.
You can get other formats, but it's even more implementation specific.
Don't standardize anything. While markdown isn't perfect the way it is now, there's no real change possible that wouldn't make markdown worse. There are two paths forward, as I see it:
Give up and use reStructuredText for all new projects.
RST is fussy, but has definite and clear solutions to the issues that plague markdown.
It has support for every major output format, and it wouldn't be too hard to expand on that.
In addition to the primary implementation, Pandoc supports python and there are early stage Java/PHP implementations. Most tools just wrap the Python implementation, which isn't really a problem.
There are clear paths for extending rst as needed for new projects.
Design and implement a new markdown -like implementation. I think reMarkdown would be a good name. This will be a lot of work, and have the following components:
a complete test suite that other implementations could use to confirm compatibility with reMarkdown.
a formal specification.
a lexer/parser design and reference implementation. With an abstract XML-like output format. We want a realistic model implementation that isn't overly dependent upon a single output format.
an explicit and defined process for changing and improving the syntax.