Elsa

Weell, it's not completely untyped, but it is runtime type-checked. There's stuff like `(if (integerp foo)` and `(defcustom ... :type '(choice (const tag "abs" abs) 'integer))` And then there are more ambitious projects like the static analyzer and language server https://github.com/emacs-elsa/Elsa I haven't tried Elsa yet since it seems to require setting up a package manager like Eask (I don't really understand why I have to install a package manager to run a language server, especially when they support four emacs-specific package managers?) and the docs were very light on whether eglot is supported or just lsp-mode.

I like the ubiquitous type inference. It reminds me a bit of ELSA for Emacs Lisp: https://github.com/emacs-elsa/Elsa. In particular, type aware macros have been on my wishlist forever: there's no good reason I shouldn't be able to write, e.g. an elisp or CL/SBCL compiler-macro that specializes an operation based on its inferred type. In normal lisps, it's hard to get even the declared types. That said, I wish that part of Loon were less coupled to the allocation model though. What made you opt for mandatory manual memory management in an otherwise high-level language? And effects? There are two things common in language design that, honestly, strike me as unnecessary: 1. manual allocation and lifetime stacking, and 2. algebraic effects. On 1: I think we often conflate the benefits of Rust-style mutability-xor-aliased reference discipline

I'd say elisp is a competitive lisp in its own right, at least at the language level. There's even a promising gradual typing system: https://github.com/emacs-elsa/Elsa

After trying Typed Clojure, liking it, but giving it up because of Clojure's GPL-incompatible license, I got interested in Kawa Scheme because it has some rudimentary form of type checking. For example, this produces warnings: (define (f1 x::String y::String) (x:concat y)) (define (f2) (f1 3 3)) ;; /dev/tty:3:19: warning - type integer is incompatible with required type java.lang.String ;; /dev/tty:3:21: warning - type integer is incompatible with required type java.lang.String ;; /dev/tty:3:15: warning - cannot convert literal (of type gnu.math.IntNum) to Type java.lang.String ;; /dev/tty:3:15: warning - cannot convert literal (of type gnu.math.IntNum) to Type java.lang.String Unfortunately it does not support fully static type checking nor generics, otherwise it would be my favorite scripting language hands down. As for ty