sligh VS edsl

But, you still seem hung up on this, so here’s actual code: https://github.com/amw-zero/sligh/blob/main/lib/codegen.ml.

Of course. Here was the first incarnation: https://github.com/amw-zero/sligh. It has a decent overview of the idea in the readme. To sum it up here, the idea is: have a language built around model-driven development and model-based testing, where you write a simple model of an application, and the implementation and model-based tests are compiled for you. I wrote about the overall model-based testing strategy here. This idea comes from self-certifying compilers that produce proofs of their correctness such as Cogent, but we drop the formality requirement and use property-based testing to compare the implementation and model.

Honorable mention - I’m working on a language with similar goals: Sligh, and I’ve written about why I think it’s such a compelling idea before as well too.

In Sligh, I spent most of the last month introducing a new intermediate representation to make tier splitting (choosing if code should live on the client or server) easier. My goal was to enable derived data, as in a model that queries other models for its data and combines them by processing them in memory. I've been using the example of a personal finance application, so imagine:

The language that I work on is Sligh, and it's out of the bulleted list because it's nowhere near as mature as any of those that I listed, and I'm more of a verification enthusiast vs. expert. Almost all of the ideas in it are borrowed from somewhere else, but I think the one quasi-unique idea is it allows you to write a pure logical description / specification of an application, and it generates full-stack web application code from that.

I’m currently using Pest, though I wouldn’t exactly recommend my compiler as a ‘good example’ just yet because I’m prototyping and just churning code out.

Sligh

So tactically it’s currently a source-to-source compiler, where in the source language (my language) you denote the system state transitions, i.e. by writing create!, update!, etc, and those get compiled to corresponding client and server code in the target language (JS for now, but hoping to support WebAssembly in the future). Heres an example program. The compiler source is there too. I’m hacking it together right now, so it’s not my finest work :D

I'm taking a brief detour from working on my actual language to work on some underlying theory. My language (Sligh) is based on informal certifying compilation, i.e. the compiler generates a test checking for correctness of the compiled program instead of a proof. Because I'm mostly interested in generating code for full-stack web applications, I think optimization is actually essential for the practicality of this approach, otherwise the certificate test will be much less effective.

So, full compilation of the implementation is out in my mind, and the next best thing is at least deriving the implementation from the model so you can leverage the logic you've already defined. That's where metaprogramming comes in, and that's what I'm playing around with here.