Does that not also suggest (cautious, make sure we back it up with our actions) optimism about this acquisition? We're not breaking up the band. These tools will be in the same hands as before. And it would be extremely value-destructive to bring in a team like ours and then undermine what made us valued and successful.
The parser is not the hard part. The hard part is doing something useful with the parse trees. They even chose "oh is that all?" and a picture of a piece of cake as the teaser image for my Strange Loop talk on this subject!
I've been in the industry for similarly long, and I understand and sympathize with this view. All I can say is that _right now_, we're committed to maintaining our open-source tools with the same level of effort, care, and attention to detail as before. That does not change with this acquisition. No one can guarantee how motives, incentives, and decisions might change years down the line. But that's why we bake optionality into it with the tools being permissively licensed. That makes the worst-case scenarios have the shape of "fork and move on", and not "software disappears forever".
> My understand is Astral's focus for ty has been on making a good experience for common issues, whereas they plan for very high compliance but difficult or rare edge cases aren't are prioritized.
I would say that's true in terms of prioritization (there's a lot to do!), but not in terms of the final user experience that we are aiming for. We're not planning on punting on anything in the conformance suite, for instance.
If you run a type checker like ty or pyright they're not decorative — you'll get clear diagnostics for that particular example [1], and any other type errors you might have. You can set up CI so that e.g. blocks PRs from being merged, just like any other test failure.
If you mean types not being checked at runtime, the consensus is that most users don't want to pay the cost of the checks every time the program is run. It's more cost-effective to do those checks at development/test/CI time using a type checker, as described above. But if you _do_ want that, you can opt in to that using something like beartype [2].
There have been some early proposals to add something like that, but none of them have made it very far yet. As you might imagine, it's a hard problem!
There was a hang/performance bug [1, 2] that was reported just after the beta release, which we've since fixed [3]. You might try seeing if we get through your entire project now?
(And as an aside, there _is_ a verbose mode: if you add `-vv` you'll get DEBUG-level log messages printing out the name of each file as we start to check it, and you can set TY_MAX_PARALLELISM=1 in your env to make it very clear which file is causing the hang. That's how we debug these kinds of issues when they're reported to us.)
Yes, we love TypeForm! We plan to support it as soon as the PEP for it lands. Under the covers, we already support much of what's needed, and use it for some of our special-cased functions like `ty_extensions.is_equivalent_to` [1,2]. TypeForm proper has been lower on the priority list mostly because we have a large enough backlog as it is, and that lets us wait to make sure there aren't any last-minute changes to the syntax.
Stepping away from Forth in particular, one of the benefits of a stack-based / concatenative language is that it's easy to implement on constrained hardware. uxn [1] is a great example of that.
And shameless self-promotion, if you're interested in how these kinds of languages compare with more traditional named-based languages, with more theoretical constructs like the lambda calculus and combinatory logic, and with gadgets like a PyBadge — well you're in luck! I gave a talk about exactly that at the final Strange Loop [2].
Note that we're not ever spinning up a Python interpreter to run your code, or monitoring an existing running Python process. So we do need some kind of metadata.
But yes, if you have a Python version specified in pyproject.toml, we respect that, and if you have a virtualenv, we can see the Python version that was used to create that. And that's what we use to type-check your code.
The default being discussed here is what we fall back on if that project metadata isn't available.
We are planning on shipping an LSP front end, and the goal is for that to include code completions. Though to set expectations, they will probably not be that sophisticated on day one. There's a lot of interesting work that we could do here, but it will take time!
We're definitely thinking hard about the ergonomics of our error messages! We're drawing inspiration from rustc and miette for the diagnostic model, and are aiming for a quality bar on par with rustc for their content.
The code is definitely open source from a licensing perspective, but we are also trying to ensure that a healthy community forms around our tools as well. We've been developing ty in the open for the last year or so, and it already includes significant work from external contributors. This is definitely not a project where only Astral-paid engineers can contribute.
Yes, if you have a Python version specifed in pyproject.toml, for instance, we respect that, and that's what we use to type-check your code. The default being discussed here is what we fall back on if that project metadata isn't available.
To add to the complexity, you have to worry about not just which language you're analyzing, but also which language the type-checker is implemented in.
So if we were to do this for ty, we would have to carefully design the internal data types and algorithms that we use to model Python code, so that they're extensible in a robust way.
But we would also have to decide what kind of Rust plugin architecture to use. (Embed a Lua interpreter? dlopen plugins at runtime? Sidecar process communication over stdin/stdout?)
Solvable problems, to be sure, but it adds to the amount of work that's needed to support this well — which in turn affects our decisions about whether/when to prioritize this relative to other features.
At least for the moment, we aren't planning on a plugin architecture. We do recognize that there are some popular libraries and code patterns that aren't easily (or at all) typeable with the current state of the typing spec. We feel it would be more useful to help drive changes to the typing spec where we can, so that other type checkers can also benefit; and/or implement workarounds for the most popular libraries directly in ty, so that a library author doesn't have to rely on their downstream consumers installing a particular set of plugins to get good type-checker results.
(It's also more difficult to support plugins effectively in a type checker like ty, than in a linter like ruff, since any non-trivial use case would likely require deep changes to how we represent types and how we implement type inference. That's not something that lends itself to a couple of simple hook extension points.)