Seong Jae Lee
2.2 KiB
CommonMark
Why is a spec needed?
John Gruber’s canonical description of Markdown’s syntax does not specify the syntax unambiguously.
In the absence of a spec, early implementers consulted the original Markdown.pl code to resolve these ambiguities. But Markdown.pl was quite buggy, and gave manifestly bad results in many cases, so it was not a satisfactory replacement for a spec.
Because there is no unambiguous spec, implementations have diverged considerably. As a result, users are often surprised to find that a document that renders one way on one system (say, a GitHub wiki) renders differently on another (say, converting to docbook using Pandoc). To make matters worse, because nothing in Markdown counts as a “syntax error,” the divergence often isn't discovered right away.
There's no standard test suite for Markdown; the unofficial MDTest is the closest thing we have. The only way to resolve Markdown ambiguities and inconsistencies is Babelmark, which compares the output of 20+ implementations of Markdown against each other to see if a consensus emerges.
We propose a standard, unambiguous syntax specification for Markdown, along with a suite of comprehensive tests to validate Markdown implementations against this specification. We believe this is necessary, even essential, for the future of Markdown.
That's what we call CommonMark.
Who are you?
We're a group of Markdown fans who either work at companies with industrial scale deployments of Markdown, have written Markdown parsers, have extensive experience supporting Markdown with end users – or all of the above.
- John MacFarlane, jgm@berkeley.edu
- David Greenspan, david@meteor.com
- Vicent Marti, vicent@github.com
- Neil Williams, neil@reddit.com
- Benjamin Dumke-von der Ehe, ben@stackexchange.com
- Jeff Atwood, jatwood@codinghorror.com
When is the spec final?
The current version of the CommonMark spec is complete (two years in the making!), but provisional pending public feedback, testing, and evaluation.
With your help, we plan to announce a finalized 1.0 spec and test suite in the next few months, along with implementations in many different languages.