[mapcars]

> You don't get the program crashing from mistyping as one would in C.

Sorry but I don't compare to C anymore, I want the same safety as in Rust or Typescript: exhaustive checks, control-flow type narrowing, mapped types and so on. Some detection at compile time is not enough, since there is a way to eliminate all type errors I want to eliminate them all, not some.

[guenthert]

Why stop there? Why not demand proof of correctness? After all, that's now within reach using LLMs producing the formal specification from a simple prompt, right?

SBCL does a fine job in detecting type mismatches within the frame of ANSI Common Lisp, not Haskell. While I would agree that a strict type system eases long term maintenance of large systems, for "explorative computing", proof-of-concepts, RAD or similar that tends to get in the way. And if such proof-of-concept looks promising, then there is no shame in rewriting it in a language more suitable for scale and maintenance.

[mapcars]

Proof of correctness would be fantastic, but I have yet to see it in action. LLMs maybe could do it for simple program, but I'm pretty sure it will fail in large codebases (due to context limits), and types help a lot in that case.

> for "explorative computing", proof-of-concepts, RAD or similar that tends to get in the way

I would even argue that its better to have typed system even for POCs, because things change fast and it very often leads to type errors that need to be discovered. At least when I did that I often would do manual tests after changes just to check if things work, with typing in place this time can also be minimised.