Groovy等效于Scala隐式参数 - 扩展 [英] Groovy equivalent for Scala implicit parameters - extended

问题描述

此问题扩展了我之前的问题对于Scala隐式参数，Groovy等效

This question extends my previous one Groovy equivalent for Scala implicit parameters

不知道这是否是从上一个主题开发的正确方法，但无论如何..

Not sure if this is the right way to develop from a previous topic, but anyway..

寻找一种方式来表达在groovy这样的东西：

I am looking for a way to express in groovy something like this:

// scala
object A {
    def doSomethingWith(implicit i:Int) = println ("Got "+i)
}
implicit var x = 5

A.doSomethingWith(6)  // Got 6
A.doSomethingWith     // Got 5

x = 0
A.doSomethingWith     // Got 0

一般来说，我想执行一段逻辑，并在其中根据执行上下文解析变量。
在scala中的隐含我似乎能够控制这种情况。

In general, I would like to execute a piece of logic, and have variables in it resolved based on the execution 'context'. With implicits in scala I seem to be able to control this scenario. I am trying to find a way to do something similar in groovy.

根据第一个问题的反馈，我试图这样来处理：

Based on the feedback from the first question I tried to approach it like this:

// groovy
class A {
    static Closure getDoSomethingWith() {return { i = value -> println "Got $i" }} 
}

value = 5

A.doSomethingWith(6)  // Got 6
A.doSomethingWith()   /* breaks with
                         Caught: groovy.lang.MissingPropertyException: 
                         No such property: value for class: A */

现在，我在 http中查看了groovy闭包定义：//groovy.codehaus.org/Closures+-+Formal+Definition

根据我的理解，当getter被调用时，失败发生为编译器不能静态地确定值可用

As I understand it, when the getter is called, the failure happens as "the compiler cannot statically determine that 'value' is available"

那么，有没有人对这种情况有建议？干杯

So, has anyone a suggestion for this scenario? Cheers

推荐答案

您也可以尝试更改返回的Closure的委托：

You could also try changing the delegate of the returned Closure:

value = 5

Closure clos = A.doSomethingWith

// Set the closure delegate
clos.delegate = [ value: value ]

clos(6)  // Got 6
clos()   // Got 5

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