An interactive interpreter prompt is essential A really solid library ecosystem Great HTTP and JSON support with minimal hassle

REPL, lexical scoping, true macros

I'll use anything but to enjoy the experience I need: 1) Statically typed functional programming 2) Vibrant library ecosystem 3) Great dev tooling (IDE, build tool, package manager)

Examples, samples and doc - Easy setup and deploy - Cross platform - Easy debug

REPL with interactive help/inspection. Good ecosystem for primary purpose. Sensible packaging and distribution.

Emojis

- Good concurrency support - Pattern Matching - Should work with Erlang VM 😉

I don't have hard requirements, but I would say: - deterministic destructors (like C++, but "with" in python or "using()" is C# are nice to have) - nice syntax (I really dislike most of functional syntaxes) - not too confusing to learn (I manage C++'s TMP but stuggle with Rust)

Priming :p

Semicolons. Definitely the semicolons.