The Julia programming language
Julia is a high level, high performance, dynamic language for technical computing.
Julia is fast: It was designed from the beginning for high performance. Julia programs JIT compile to efficient native code for multiple systems and architectures via LLVM.
Julia is general: It uses multiple dispatch as a paradigm, making it easy to express object oriented and functional programming patterns. The standard library provides asynchronous I/O, process control, logging, profiling, a package manager, and more. In addition, there is a rich ecosystem of over 10,000 packages and counting across a number of domains.
Julia is easy to use: It has high level syntax and is dynamically typed, providing accessibility for programmers of all backgrounds and experience levels, and making it feel like a scripting language.
Julia is optionally typed: It has an extensive, flexible, and extensible type system, and type declarations can be used to clarify and solidify programs. But type declarations are not required for general use.
Julia is open source: It's free for anyone to use, and the source code is publicly available under a permissive license on GitHub (https://github.com/JuliaLang/julia).