Have you looked at the Lisps / Scheme / Racket yet? Racket in particular makes it quite nice to go #lang blah at the top of the file and change the parsing or interpretation entirely.

For example all the documentation pages and guides are written in scribble:

https://docs.racket-lang.org/scribble/getting-started.html#(part._first-example)

#lang scribble/base
 
@title{On the Cookie-Eating Habits of Mice}
 
If you give a mouse a cookie, he's going to ask for a
glass of milk.

And it has an entire document markup language created in it, which can output pdf or html. But you can still use @ syntax to drop in racket code to compute values. Or create templates.

I even implemented a #lang which took assembly directly (and interpreted it, it was for a class).

So if you are really after full control, you should study Lisps and their macro systems.

Thanks, you made me feel old today. Get off my lawn.

I’ve watched some slow typists program, and I think I have the answer. If it takes you a while to type the code out, you are much more likely to stick to the first approach that works, and not rewrite it as much.

Uh you’re not going to believe this, but the parents volunteered the boys.

You only read about the ones that get caught though…

You remember that orange soap you put in dry hands, and only after lathering wash with water? My hands never felt cleaner than after autoship class.