Thoughts on how to make CSS extraction safe

[alex35mil]

The stumbling blocks of static extraction in ReScript:

• PPX has access only to code AST it wraps, nothing else
• PPX can't emit side effects

In the current state of things, I see no way to implement static extraction with PPX-only. But it can be split in 2 steps:

1. ReScript part: PPX parses CSS and generates sound CSS functions
2. Bundler: parses generated JS from ReScript and transforms CSS functions generated by PPX back into static CSS. Output is: classnames in.js + CSS code in .css.

Basically, step 2 is reimplementation of Linaria but for ReScript.

It's a lot of work.