Enumeration of the content types.

Technically document is also a content type, which includes containers (lists, block quotes) and flow. As ContentType is used on tokens to define the type of subcontent but document is the highest level of content, so it’s not listed here.

Containers in markdown come from the margin and include more constructs on the lines that define them. Take for example a block quote with a paragraph inside it (such as > asd).

flow represents the sections, such as headings, code, and content, which is also parsed per line An example is HTML, which has a certain starting condition (such as <script> on its own line), then continues for a while, until an end condition is found (such as </style>). If that line with an end condition is never found, that flow goes until the end.

content is zero or more definitions, and then zero or one paragraph. It’s a weird one, and needed to make certain edge cases around definitions spec compliant. Definitions are unlike other things in markdown, in that they behave like text in that they can contain arbitrary line endings, but have to end at a line ending. If they end in something else, the whole definition instead is seen as a paragraph.

The content in markdown first needs to be parsed up to this level to figure out which things are defined, for the whole document, before continuing on with text, as whether a link or image reference forms or not depends on whether it’s defined. This unfortunately prevents a true streaming markdown to HTML compiler.

text contains phrasing content such as attention (emphasis, strong), media (links, images), and actual text.

string is a limited text like content type which only allows character references and character escapes. It exists in things such as identifiers (media references, definitions), titles, or URLs.