Lambda Calculus (also written as λ-calculus) is a formal system in mathematical logic for expressing computation based on function abstraction and application using variable binding and substitution. Introduced by Alonzo Church in the 1930s, it is a universal model of computation that can be used to simulate any Turing machine.
The system has applications in many different areas in mathematics, philosophy, linguistics, computer science, and it has played an important role in the development of the theory of programming languages as well as functional programming languages.
Here are several input examples for the interpreter:
(\x.x)(\y.y)(\z.z)
(\x.x)y
(\x.(\y.xy))y
(λvw.v)xy
I(\x.x)
SKI(KIS)
The full documentation for the code can be found here.
The link to the original Wikipedia article can be found here.