Key difference here is that it's not aiming to be a comprehensive type system, just to catch obvious problems. So if it runs into something it doesn't understand it'll just move on and leave it as is. If it sees something it understands and it's incorrect it will give an error.
Personally, I would find this very valuable because it would help catch many common errors early while staying completely out of the way.
And yeah, I can't really do development without the REPL anymore. I find the REPL makes the whole experience a lot more enjoyable and engaging than the compile and test cycle. It's really a shame that most languages still don't provide this workflow.
Didn't core.typed try to do the same thing? Not provide comprehensive types but just as needed? I never really used it (a coworker did but ended up throwing it out I think). Even if it's exactly the same technically maybe it'll work out with a different set of social circumstances. Maybe if Circle didn't drop core.typed it'd be even more popular now. Never know about these things.
Haha, well that's where you and I differ. The REPL is amazing, but I still want my ability to create closed world assumptions first!
Core typed requires you to annotate everything in the namespace, or add exclusions explicitly. This introduces quite a bit of additional work, and I suspect that's why it never really caught on.
I've read that the author is looking at improving inference in it, and at generating types from Spec, so it might still find a niche after all.
And I understand completely, it's all about perceived pain points at the end of the day, and we all optimize for different things based on our experience and the domain we're working in. That's why it's nice to have lots of different languages that fit the way different people think. :)
Personally, I would find this very valuable because it would help catch many common errors early while staying completely out of the way.
And yeah, I can't really do development without the REPL anymore. I find the REPL makes the whole experience a lot more enjoyable and engaging than the compile and test cycle. It's really a shame that most languages still don't provide this workflow.