Java表达式树 [英] Java Expression Trees

问题描述

是否有 .net 的表达式树为 JVM 提供LINQ？我想在 Scala 中实现一些类似LINQ的代码结构，我想知道是否还要滚动我自己的表达式树库。

Is there an equivalent of .net's Expression Trees that underly LINQ for the JVM? I would like to implement some LINQ like code structures in Scala and I am wondering if I have to roll my own expression tree library also.

更新：
我对linq等价物本身不感兴趣。 .net有一大组表达式树工具，可以很容易地在运行时动态编译代码，可以从代码中调用它。我想进行的项目与数据库无关。表达式树提供了一种简单的方法来描述对数据进行操作的代码。

Update: I am not interested in a linq equivalent itself. .net has a large set of expression tree tools that make it easy to dynamically compile code at runtime can have it be callable from your code. The project I want to undertake has no relation to databases. Expression tree's provide an easy way to describe code that operates on data.

如果没有库我的其他选项我认为是创建一个发出字节代码的库。

If there is no library my other option I think is to create one that emits byte code.

推荐答案

从2.10开始，Scala有了宏，它允许您在编译时访问其参数的抽象语法树： http://scalamacros.org/ 。以下是一些使用示例，包括LINQ草图： http：// scalamacros。 org / paperstalks / 2013-12-02-WhatAreMacrosGoodFor.pdf 。

Since 2.10, Scala has macros, which give you access to abstract syntax trees of their arguments at compile-time: http://scalamacros.org/. Here are some examples of their usage including a sketch of LINQ: http://scalamacros.org/paperstalks/2013-12-02-WhatAreMacrosGoodFor.pdf.

这篇关于Java表达式树的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！