Fennel is a programming language that brings together the speed, simplicity and reach of Lua with the flexibility of a lisp syntax and macro system. Full Lua compatibility: Easily call any Lua function or library from Fennel and vice-versa. Zero overhead: Compiled code should be just as efficient as hand-written Lua. Compile-time macros: Ship compiled code with no runtime dependency on Fennel. Embeddable: Fennel is a one-file library as well as an executable. Embed it in other programs to support runtime extensibility and interactive development. Anywhere you can run Lua code, you can run Fennel code. Fennel is a lisp that compiles to Lua. It aims to be easy to use, expressive and has almost zero overhead compared to writing Lua directly. Building Fennel from source allows you to use versions of Fennel that haven't been released, and it makes contributing to Fennel easier.