The Github fork of cmark supports several markdown extensions which provide features which are not (yet) in the official commonmark spec.
Details
Currently the following extensions are supported:
table support rendering of tables: gfm-spec section 4.10
strikethrough via
~~sometext~~
syntax: gfm-spec section 6.5autolink automatically turn URLs into hyperlinks: gfm-spec section 6.9
tagfilter blacklist html tags:
title
textarea
style
xmp
iframe
noembed
noframes
script
plaintext
: gfm-spec section 6.11tasklist turns certain list items into checkboxes: gfm-spec section 5.3
See the full spec for GitHub Flavored Markdown.
Examples
print(list_extensions())
#> [1] "table" "strikethrough" "autolink" "tagfilter"
#> [5] "tasklist"