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：面向目标的编程(OOP)是用于建立软件系统的最受欢迎的范例之一,然而,尽管OOP在工业和学术上很受欢迎,但仍然缺少类似于美元计算的正式装置,而美元计算是功能性编程的基础。曾几次尝试将OOP正式化,但其中没有任何一次尝试能够涵盖现代OO编程语言的所有功能,如C++或Java。我们又尝试并创建了美元计算器。我们还创建了EOLANG(也称为EO),这是一种实验性编程语言,以美元计算。