clojure - Clojure 协议(protocol)源自哪种语言的哪些特性？

Question

Clojure 协议(protocol)源自哪种语言的哪些特性？

注意:这不是一个关于“如何使用协议(protocol)”的问题

这是一个关于这个想法的灵感来源的问题。

特别是，我想要的是得到类似的东西:

• XYZ + ABC 启发的 Clojure 协议(protocol)

然后，我可以去阅读人们使用 XYZ 和 ABC 来了解语言功能的说明。

谢谢!

Answer 1

如果您了解 Java，Clojure 协议(protocol)与 Java 接口(interface)类似 - 但更好。 Clojure website说了有关协议(protocol)的内容(该页面上有更多有关协议(protocol)的背景信息和基本原理):

• Provide a high-performance, dynamic polymorphism construct as an alternative to interfaces
• Support the best parts of interfaces
  • specification only, no implementation
  • a single type can implement multiple protocols
• While avoiding some of the drawbacks
  • Which interfaces are implemented is a design-time choice of the type author, cannot be extended later (although interface injection might eventually address this)
  • implementing an interface creates an isa/instanceof type relationship and hierarchy
• Avoid the 'expression problem' by allowing independent extension of the set of types, protocols, and implementations of protocols on types, by different parties
  • do so without wrappers/adapters
• Support the 90% case of multimethods (single dispatch on type) while providing higher-level abstraction/organization

此外，您可能会发现 Solving the Expression Problem with Clojure 1.2有趣的读物:

Clojure expert Stuart Sierra introduces you to new features in Clojure 1.2 that solve the Expression Problem, a classic programming dilemma. Protocols let you extend preexisting types to new methods, and datatypes let you extend preexisting methods to new types — all without changing the existing code. You'll also see how Java™ interfaces and classes can interact with Clojure protocols and datatypes.