boba VS xvm

I've done a small implementation, used in type inference, in my language Boba. And you are correct, I used the linear equation solving method.

The vast majority of October's improvements on Boba were type system and runtime bug fixes. In particular, the effect handler/delimited continuation semantics were hopelessly busted beyond a few simple examples I'd fixated on.

September was another productive month for Boba, which is starting to get more 'quality of life' improvements rather than broad new features. That doesn't make the work less important: one of the bug fixes to the type inference engine last month caught a previously unseen bug in the core Boba libraries!

Also worth checking out is Adam Gundry's work on type inference for UoM types. Or, if you want an example implementation of the Abelian unification used in standard type inference extended with UoM types, you can reference my implementation, based on solving linear equations.

August was a surprisingly productive month for the Boba compiler. A few highlights:

The next large feature for Boba (a general-purpose concatenative language) is language integrated property tests.

That's a good question! I wrote up some of my thoughts on the benefits of Go as a backend, but there's also a historical component here. The first backend I was experimenting with was compile-to-C plus a C-based runtime. Go was closer to C than C# for what I needed at the time and I thought had a nicer concurrency story as a backend.

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: