Compiler refactoring

[janis-me]

The compiler needs to undergo changes, in order to support more features and fix some bugs. The main issues I see right now:

• We compile files one-by-one
• Files that are loaded twice, are run twice. That's an issue, for example for custom properties defined in the root. See Custom properties are defined once for every import #37
• We can't have multiple entrypoints
• The watch mode does not currently re-use the rolldown instance
• CLI Arg parsing is bad

And more importantly, we need to define how surimi code is shared across modules, how surimi code can be imported by ts modules (and end up in the final build) and also how the compiler picks up styles and compiles them.

One of the biggest issues is that builders like the SelectorBuilder cannot and should not be imported into non-surimi files. there is no value and it would require runtime. On the other hand, generated class names and CSS custom property names might very well be used and imported as strings.

How can we

1. Make it clear to users what they can and can not import into .ts files?
2. Ensure the compiler compiles away all surimi code so no runtime is needed
3. Not have any magic that changes variable types (from class to string)

[janis-me]

My ideas for solving some of these points:

• Every surimi class has a build() method, that
  1. finalizes the builder/class and returns a string
  2. adds the styles to the current postcss root (.style() would not!)
• The compiler goes through each .css.ts file and transforms it by calling .build, for all surimi builders, if not already called.
• It also transforms the files by adding Sruimi.build at the end to generate the CSS and exports it via __SURIMI_GENERATED_CSS__ just like before.
• When one .css.ts file imports another, it will receive the original file, thus still having access to all the builder classes.

Each file would still be compiled individually, but now they would not "interfere" each other. We can also leave the full resolving / loading of files part to vite (in vite mode), I think.

For the other issues like re-rusing rolldown in watch mode, we can design the new compiler in a way that is flexible to run in "standalone" mode, compile multiple or single files, and also integrate properly with vite.

[janis-me]

Changed my mind about this.

We will NOT mess with changing an AST or something like this for now. Instead, the compiler / vite plugin should just make sure to only include CSS files once in the build.

The points about CLI arguments and the watch mode being bad still stand. Need to work on that. But as far as I can tell, the compiler now works quite okay

[janis-me]

Linking #59 to think about the Compiler performance, and how to cache compilation results cross-context (cc @ixexel661 )