# Lambda Calculus

First developed by American mathematician Alonzo Church in the 1930s, **lambda calculus** is a formal system for expressing computation based on the abstraction of functions. It is a foundational principle in mathematical logic. More plainly, lambda calculus aims to be a simple system of computation that is an alternative to the "hardware" approach used by Turing machines.

## How is lambda calculus used?

In computer programming, lambda calculus is used to anonymize functions, allowing them to be referred to in the abstract sense. This action makes them first-class objects: they can be operated on just like any other entity in the language. For example, an anonymous function can be passed to other functions as a parameter.

One of the first programming languages to use anonymous functions was LISP. The special word lambda in LISP defines a function without giving it a name. For instance, the function x + 2 can be defined anonymously in LISP with the following statement:

(lambda (x) (+ x 2))

Anonymous functions are an important part of many modern programming languages, including JavaScript.

Knights of Lambda Calculus, Logic, Programming terms, Syntactic sugar