sligh VS xvm

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

Have a look at the ecstasy library for the language definitions of these types.

2) Funky interfaces: This is an Ecstasy interface that declares abstract static members (e.g. functions), which can then be implemented on any class and overridden on any sub-class, such that they can be invoked by type (instead of this), and virtually resolved (late bound at runtime) based on the type known at compile time. The best known example, of course, is Hashable, because it has to guarantee that a type implements both equals() and hashCode() on the same class, and the implementation is tied to the type, and not to the this. (C# added a similar feature last year in version 11.)

I'm just going to warn you in advance that invocation is one of the hardest things in the compiler to make easy. In other words, the nicer your language's "developer experience" is around invocation, the more hell you're going to have to go through to get there. The AST nodes for Name( (NameExpression) and Invoke( (InvocationExpression) alone are 7kloc in the Ecstasy implementation, for example -- but the result is well worth it.

Ecstasy uses message passing automatically behind the scenes for asynchronous calls, but the message passing isn't visible at the language level (i.e. there is no "message object" or something like that visible). Basically, all Ecstasy code is executing on a fiber inside a service, and services are all running concurrently, so from any service realm to any service realm, the communication is by message.

Regarding Ecstasy, we did not set out to build a new language; we actually set out to solve a real world problem. Specifically, we wanted to be able to dramatically improve the density of workloads in data centers, by at least two orders of magnitude in the case of lightly used applications. Our initial goal was to create a runtime design that would support 10,000 stateful application instances on a single server. Let's call it the "a10k" problem 🤣 ... a tribute to the c10k problem from 1999. We refer to our goal as "zero carbon compute", i.e. we want to push the power and hardware cost for an application to as close to zero as possible; you can't reach zero, but you can get close. If we succeed, we will help reduce the electricity used in data centers over the next few decades by a significant percentage.

Generally, left to right, one character at a time. If you’re looking for example code, here’s a simple hand-built lexer.

Parts of Ecstasy are now implemented in Ecstasy. Here's the Lexer, for example.

Ecstasy

Ecstasy and the xvm were designed assuming an adaptive runtime compiler (similar in concept to the Hotspot compiler for Java), but not necessarily using a JIT.

A Future reference has the various capabilities that you'd imagine, taking lambdas for thenDo(), whenComplete(), etc. The reference, in the above example, is a local variable, so you just obtain it using the C-style & operator: