Salt v1.0.0 – a systems language with Z3 theorem proving in the compiler

Salt v1.0.0 – a systems language with Z3 theorem proving in the compiler(salt-lang.dev)

16 points by bneb-dev 3 hours ago | 7 comments

csb6 1 hour ago |

For people looking for other languages with statically checked contracts, you might want to check out SPARK, which has been around in some form since the late 1980s. It is a subset of the Ada language and had been used for safety critical code in aerospace and defense projects, as well as for some Nvidia firmware.

It also uses Z3 to discharge proof obligations generated by the contract annotations, and it lets you use swap out different theorem provers as backends.

The GNAT Ada compiler (which is part of GCC) allows you to turn off the dynamic safety checks that are usually inserted into Ada programs at build time so you can optionally remove them if they are proven unnecessary.

Here are some resources for comparison:

- https://www.adacore.com/languages/spark

- https://learn.adacore.com/courses/intro-to-spark/chapters/01...

bneb-dev 1 hour ago | |

SPARK seems interesting. Any ideas how it compares to Salt?

- C performance? - Generics? - Syntax ergonomics?

Thanks for sharing!

csb6 1 hour ago | | |

Yes, it has generics. The syntax is Pascal-like, which some people used to C-family languages dislike but I personally find nice. Performance can definitely match performant C code. (intended use cases include real-time systems and embedded devices)

The language overview can be found here: https://docs.adacore.com/spark2014-docs/html/ug/en/spark_201...

skybrian 2 hours ago |

This looks pretty impressive but it’s all AI-generated (or written in a similar style) and therefore the documentation is lacking.

There is a language specification [1][2] but it lacks coherence.

I think the way to improve it would be to try to teach this language to people and get feedback from them. That is, it needs beta testers. It looks like there’s no community of users yet?

[1] https://github.com/bneb/lattice/blob/main/docs/SPEC.md

[2] https://github.com/bneb/lattice/blob/main/SYNTAX.md

bneb-dev 1 hour ago | |

For complete transparency: AI augmented engineering is the core workflow for this project.

I have been pretty diligent about trying to de-slop the project after long RALPH loops and `/goal` prompts, and I review and edit documentation. Based on your feedback, I just made another pass.

Please feel free to let me know if there is anything specific lacking from the docs, and I will update them in the future.

skybrian 51 minutes ago | | |

If you compare say, the Go language specification for an assignment statement [1] to Salt's explanation of its let statement, there is a big difference. Salt's docs lean heavily on "it works like you would expect from other languages" so you have to reason by analogy. A specification shouldn't work that way; it should actually explain the rules for each language construct, without assuming knowledge of other languages.

[1] https://go.dev/ref/spec#Assignment_statements

luckystarr 2 hours ago |

> [int overflows, etc.] No runtime cost when Z3 can prove it. Otherwise, the compiler emits a safe runtime check as fallback.

Super interesting approach. I see this eventually be integrated into future mainstream languages, though that may take a while. I suspect that the game programming crowd will try to use it first, due to the possibility to prove certain edge cases at compile time and skip the runtime cost. But perhaps this optimization drive is no longer the case because we've got bazillions of cores nowadays. I may be too old for these predictions. Cool nonetheless.

bneb-dev 1 hour ago | |

Thanks for reading and sharing your thoughts!