Standard ML
Standard ML (SML) is a general-purpose programming language that supports functional, imperative, and concurrent programming paradigms. It is mainly used for academic research, programming language theory, and development of type-safe and high-performance software systems.
Hello, world code example:
print "Hello world!\n"
Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.
Repositories on GitHub: 500,559