Yon is described as 'Experimental, topos-oriented programming language: a compiled language whose semantics are drawn from category theory (elementary topoi, Heyting algebras, directed type theory) and whose runtime stores every value in a content-addressed heap built on the Leech lattice ?' and is an app in the development category. There are more than 25 alternatives to Yon for a variety of platforms, including Linux, Mac, Windows, BSD and Web-based apps. The best Yon alternative is C (programming language), which is both free and Open Source. Other great apps like Yon are Rust, C++, Haskell and Elixir.