cmark is the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. It provides a shared library (libcmark) with functions for parsing CommonMark documents to an abstract syntax tree (AST), manipulating the AST, and rendering the document to HTML, groff man, CommonMark, or an XML representation of the AST.
Each of the R wrapping functions parses markdown and renders it to one of the output formats:
md <- " ## Test My list: - foo - bar"
markdown_html function converts markdown to HTML:
markdown_xml function gives the parse tree in xml format:
Most of the value in commonmark and is probably in the latter. There already exist a few nice markdown converters for R including the popular rmarkdown package, which uses pandoc to convert markdown to several presentation formats.
The formal commonmark spec makes markdown suitable for more strict documentation purposes, where we might currently be inclined to use json or xml. For example we could use it to parse
NEWS.md files from R packages in a way that allows for archiving and indexing individual news items, without ambiguity over indentation rules and such.