percival VS flix

Souffle and Cozo mentioned below already implement the whole of "traditional" datalog.

Percival (https://github.com/ekzhang/percival) has some very nice examples showing how you can interactively write and test rules on top of a datalog interpreter.

Bud (http://bloom-lang.net/bud/) is Hellerstein's proof of concept playground. It has bit-rotted in the past few years, but the examples are readable even if you can't easily get it working.

The complexity can be quite good. You can syntactically determine when you've written linear recursion (equivalent to a for loop) vs not. Otherwise, the complexity is what you'd expect from incremental view maintenance in a normal SQL database. Which is to say O(n^k) with k being the number of relations joined, but usually much, much less with appropriate indexes and skew in the data. All the usual tricks concerning data normalization and indexes from databases apply.

I've worked on percival a bit, it compiles (transpiles?) the datalog ast into javascript code on demand and executes it to get the results, see [1]. Percival's creator, Eric, also submitted a 10m presentation about the project [2] to the HYTRADBOI 'virtual conference' earlier this year [2]. They also submitted a Show HN that received a couple comments [3]. The Have You Tried Rubbing A Database On It conference included several awesome presentations featuring datalog, which readers may find interesting [4].

[1]: https://github.com/ekzhang/percival/blob/main/crates/perciva...

[2]: https://www.hytradboi.com/2022/percival-a-reactive-language-...

[3]: https://news.ycombinator.com/item?id=29521975

[4]: https://www.hytradboi.com/

I haven't written a parser with Chumsky, bit I've played with a little one a bit if you wanna see an example syntax. The error reporting for this project is implemented with `ariadne` which is also really slick.

Parser: https://github.com/ekzhang/percival/blob/main/crates/perciva...

Error reporting: https://github.com/ekzhang/percival/blob/main/crates/perciva...

Datalog playground: https://percival.ink/

To see an error report, delete some punctuation from one of the Datalog code blocks then press shift-return.

you can use Datalig within Flix https://flix.dev/

> recently added support for package management

Are there any [plans for] supply chain attack mitigations?

Naively searching, I find https://github.com/flix/flix/issues/4380#issuecomment-123641... (Proposed Principle: A package can be declared as "safe") and https://github.com/flix/flix/issues/2837 (Add capability-safety to polymorphic effects?) the latter closed with working on something related to this https://github.com/flix/flix/issues/3000 (The Road to Algebraic Effects).

I don't know that it's one-to-one in terms of features, but I've been impressed with the Flix language, also on the jvm: https://flix.dev/ .

You might be interested in Flix which has first-class Datalog program values:

https://flix.dev/

https://doc.flix.dev/fixpoints.html

(I am one of the developers of Flix)

I like it. Modern languages that distinguish between pure and impure programs like Flix, Koka, and Effekt do so on the type level instead of syntactically. This has three advantages:

I work almost 100% in Scala because it has the most advanced functional features (proper pattern matching, higher-kinded types, typeclasses, ...) and very powerful metaprogramming abilities, while being compatible with the Java OO model as long as you consume Java libraries (the other way around can be tricky, Kotlin is much better there). Only Flix takes it further but it's still an immature project.