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I'm doing some work in this space[1], it's a really deep and hairy problem. There's a lot that you can do at the OS level sand boxing of course, but you may wan
by ch4s3 1mo ago
I'm doing some work in this space[1], it's a really deep and hairy problem. There's a lot that you can do at the OS level sand boxing of course, but you may want some areas of you code to have network access and for some areas that use external dependencies to not have that access. Tracking where systems have side effects ends up being a lot of book keeping and a lot of languages that implement an object-capability model require you to thread caps through all of your calls, which IMO is bad ergonomics and a place where bugs creep in as functions accrue caps. Or sometimes they have rather superficial cap systems like Hack, or are rather awkward like in Deno.
[1] https://march-lang.org/docs/capabilities https://march-lang.org/docs/capabilities
- masterj 1mo agoThat's a really interesting project! Being able to assert more, statically, about what our software is doing seems like a real growing need
- ch4s3 1mo agoThank you, I really appreciate that. I'm really trying to make it easy to assert what code can do, then enforce it at compile time and optionally via the build tool at runtime via OS sandboxing integration. Supply chain attacks are also an area I'm exploring by having deps declare caps and then the build can scan and inspect binaries. It's been a real education. I talked to one of the people behind Caja and learned a lot.
- thesz 1mo agoWhy do you invent a new language for your work? Why did you not embed your language into another one, with type system that is superset of what you need? For example, there's capabilities expressed in Haskell: https://github.com/tweag/capability https://github.com/tweag/capability Capabilities there are tracked at type level and are subject to type erasure, if possible.
- tome 1mo agoI'll blow my own trumpet and promote my own Haskell capabilities library, Bluefin: https://hackage.haskell.org/package/bluefin https://hackage.haskell.org/package/bluefin Bluefin is used in production, and as far as I know capability is not.
- ch4s3 1mo agoThat looks really cool. Can you narrow Bluefin.IO to reads/writes separately? One of the things I've worked on is the ability to allow code to read files, even specific files, but deny writes.
- tome 1mo agoYeah you can write a capability that encapsulates exactly whatever effects that you like!
- ch4s3 1mo agoDid this start as an effect system and then capabilities shook out naturally?
- tome 29d agoYes! It started as an implementation of the effect system I always wanted: effects passed on the value level, rather than implicitly on the type level. Once I'd done that I realise that it was actually a capability system (and that was the better way of describing it, because more people already know what a "capability system" is).
- ch4s3 29d agoThat’s not surprising there’s a lot of mechanical overlap between the two. It’s a really interesting relationship.