Pure functional languages do not rely on operations that save or retrieve state and do not allow destructive assignments.

纯粹的函数性语言不依赖保存或检索状态的操作，因此不允许破坏性赋值。

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Instead, programs written in pure functional languages communicate by passing messages between concurrent, autonomous processes.

相反的，用纯函数式语言编写的程序在并发自主的进程中通过传递消息来通信。

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A pure functional language like Haskell might offer type hierarchies, discriminated unions, quantification, existential types, and so on, but OOP languages typically lack these things.

象Haskell那样的纯函数型语言可以提供类型层次结构、区别合并、量化、存在类型等等，但OOP语言通常缺乏这些功能。

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