Lean is an [[Apache v2]] licensed programming language and theorem prover written in [[C++]]. - [Website](https://lean-lang.org/) - [Source](https://github.com/leanprover/lean4) - [Documentation](https://lean-lang.org/documentation/) > Lean is a functional programming language that makes it easy to write correct and maintainable code. You can also use Lean as an interactive theorem prover. Lean programming primarily involves defining types and functions. This allows your focus to remain on the problem domain and manipulating its data, rather than the details of programming. \- official website # Notability # Philosophy The [Lean FRO](https://lean-fro.org/) nonprofit was launched in August of 2023. # Platform Support - x86-64 Linux with glibc 2.27+ - x86-64 macOS 10.15+ - x86-64 Windows 10+ ## Tier 2 - aarch64 Linux with glibc 2.27+ - aarch64 (Apple Silicon) macOS - x86 (32-bit) Linux - Emscripten Web Assembly # Features - Type inference - First-class functions - Powerful data types - Pattern matching - Type classes - Extensible syntax - Hygienic macros - Dependent types - Metaprogramming framework - Multithreading - Verification: you can prove properties of your functions using Lean itself # Tips # History The Lean project was launched by Leonardo de Moura when he was at Microsoft Research in 2013. # References