OCaml is a mature and statically-typed functional programming language. It is commonly used for programming language research, writing compilers and interpreters, as well as in areas such as finance and formal verification.

Hello, world code example:

print_endline "Hello world!"

Popularity: 0.7% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.

Repositories on GitHub: 31,131