title: CommonMark
role: manual
tags: #manual #markdown #zettelstore
syntax: zmk
back: 00001006000000 00001007031200 00001008000000 00001008010000 00001012920513
backward: 00001006000000 00001007000000 00001007031200 00001008000000 00001008010000 00001012920513
box-number: 1
copyright: (c) 2020-present by Detlef Stern <ds@zettelstore.de>
created: 20220113183435
forward: 00001004010000 00001007000000 00001012920500 00001012920510
lang: en
license: EUPL-1.2-or-later
modified: 20221018123145
published: 20221018123145
url: https://commonmark.org/
visibility: public

[[CommonMark|https://commonmark.org/]] is a Markdown dialect, an [[attempt|https://xkcd.com/927/]] to unify all the different, divergent dialects of Markdown by providing an unambiguous syntax specification for Markdown, together with a suite of comprehensive tests to validate implementation.

Time will show, if this attempt is successful.

However, CommonMark is a well specified Markdown dialect, in contrast to most (if not all) other dialects.
Other software adopts CommonMark somehow, notably [[GitHub Flavored Markdown|https://github.github.com/gfm/]] (GFM).
But they provide proprietary extensions, which makes it harder to change to another CommonMark implementation if needed.
Plus, they sometimes build on an older specification of CommonMark.

Zettelstore supports the latest CommonMark [[specification version 0.30 (2021-06-19)|https://spec.commonmark.org/0.30/]].
If possible, Zettelstore will adapt to newer versions when they are available.

To provide CommonMark support, Zettelstore uses currently the [[Goldmark|https://github.com/yuin/goldmark]] implementation, which passes all validation tests of CommonMark.
Internally, CommonMark is translated into some kind of super-set of [[Zettelmarkup|00001007000000]], which additionally allows to use HTML code.[^Effectively, Markdown and CommonMark are itself super-sets of HTML.]
This Zettelmarkup super-set is later [[encoded|00001012920500]], often into [[HTML|00001012920510]].
Because Zettelstore HTML encoding philosophy differs a little bit to that of CommonMark, Zettelstore itself will not pass the CommonMark test suite fully.
However, no CommonMark language element will fail to be encoded as HTML.
In most cases, the differences are not visible for an user, but only by comparing the generated HTML code.

Be aware, depending on the value of the startup configuration key [[''insecure-html''|00001004010000#insecure-html]], HTML code found within a CommonMark document or within the mentioned kind of super-set of Zettelmarkup will typically be ignored for security-related reasons.