Lambda Calculus Playground

Explore the untyped lambda calculus, one of most fundamental systems in computing. Starting with a remarkably simple set of rules, all computation is possible. But just because the rules are simple doesn't mean the lambda calculus is easy: you'll need some cleverness and creativity to get to a point where you can compute anything.

This app allows you to visually create lambda calculus expressions (lambdas, variables, and function calls) and evaluate them. Try out booleans, church numerals, or the Y combinator.

Works great on tablets! On phones, works best in landscape mode.

Note that the app does not (yet) teach the lambda calculus, so it's best to have a separate resource for that (e.g. online or a class).