[nickpsecurity]

In languages with macros (esp Lisp), you can implement HTML right inside the language. It can become both a data structure that code can be embedded into and a generator of applications.

The huge number of Flask-like stacks makes me think that’s a significant, use case. Double true if the host stack supports live updates of running applications.

You might also look up the iMatix DSL’s that had high-level constructs that compiled to low-level code.