I built an extendable full document markup language

Hi HN, I've been working on an easy to read and write extendable markup language that can express any HTML element and structure. Longform can be used in most situations Markdown might be used, but is better suited for situations where structure and semantics are a requirement of the output and are understood by a document's authors.

Longform exports full documents or HTML fragments, allowing a parent program to piece together the fragments into its own markup. And directives can be used to extend the language.

Take a look at https://longform.occultist.dev for the working spec. If you want to test it out, I've built a really basic static site generator at https://stat.occultist.dev.