Hysen LabsYo
Yo - A programming language that's LLM-friendly to write and human-friendly to read
Yo is a compiled language designed to be read by humans and models
shd101wyy/Yo is a work-in-progress, multi-paradigm compiled language that aims to be simple and close to C in speed. Its syntax is built to be easy for both people and language models to read and write.
Design goals
Yo is a multi-paradigm, general-purpose, compiled language. The README states its aim is to be simple and fast, roughly 0 to 15 percent slower than C, and the name comes from the Chinese word for pomelo, a fruit also used as the author's daughter's nickname. The syntax is inspired by Lisp S expressions to support homoiconicity and metaprogramming with a small, regular rule set that stays friendly to both human and machine readers.
Language features
The feature list includes first-class types, compile-time evaluation, closures, algebraic effects and handlers, and async or await built on a builtin Io effect. Memory safety is the default: user code cannot write undefined behavior through raw pointers, FFI, or inline assembly without an explicit opt-in pragma, and the project ships a tool to audit that unsafe surface. It also offers reference types, compile-time reference counting, and a thread-per-core parallelism model.
Tooling and build
Yo transpiles to C, so a C compiler is required to produce machine code, and the install script can build from a single-file yo.c for platforms such as NixOS. The declarative build system is inspired by Zig and Nix, with yo build, yo init, and WebAssembly targets, and projects can pin a version through a .yo-version file. The compiler is written in Yo and builds itself.
Editorial conclusion
The language ships with an install script that fetches a prebuilt compiler and is released under the UIUC/NCSA Open Source License.
Community notes