Object-oriented programming (OOP) is one of the most popular paradigms used for building software systems. However, despite its industrial and academic popularity, OOP is still missing a formal apparatus similar to $\lambda$-calculus, which functional programming is based on. There were a number of attempts to formalize OOP, but none of them managed to cover all the features available in modern OO programming languages, such as C++ or Java. We have made yet another attempt and created $\varphi$-calculus. We also created EOLANG (also called EO), an experimental programming language based on $\varphi$-calculus.

翻译：面向对象编程（OOP）是构建软件系统最常用的范式之一。然而，尽管其在工业界与学术界广受欢迎，OOP仍缺乏类似函数式编程所依赖的λ-演算的形式化体系。此前已有多次尝试对OOP进行形式化，但均未能覆盖现代面向对象编程语言（如C++或Java）中可用的全部特性。我们再次进行尝试，创建了φ-演算，并基于φ-演算开发了实验性编程语言EOLANG（亦称EO）。