在groovy中为数组重载+运算符 [英] Overloading + operator for arrays in groovy

问题描述

我是一个时髦的新手。也许这是小菜一碟，但我想重载数组/列表的+运算符来编写代码，如

  def a = [1,1,1] 
 def b = [2,2,2] 
 
 assert [3,3,3] == a + b 
  
 
 
  ArrayList.metaClass.plus<< {集合b  - > 
 [delegate，b] .transpose（）。collect {x，y  - > x + y} 
} 
  
一个更加本地化的选择是使用一个类别： / p> 
 
 
  class PlusCategory {
 public static Collection plus（Collection a，Collection b）{
 [a，b ] .transpose（）。collect {x，y  - > x + y} 
} 
} 
 use（PlusCategory）{
 assert [3，3，3] == [1,1,1] + [2，2， 2] 
} 
  
然而，我可能会创建一个通用的zipWith方法编程），允许人们轻松指定不同的行为...... 
  Collection.metaClass.zipWith = {Collection b，Closure c  - > 
 assert [3，3，3] == [1,1,1] .zipWith（[2， 2，2]）{a，b  - > a + b} 
 assert [2,2,2] == [1,1,1] .zipWith（[2,2,2]）{a，b-> a * b} 
  
 
I am a groovy newbie. Maybe this is a piece of cake, but I want to overload the + operator for arrays/lists to code like this
def a= [1,1,1]
def b= [2,2,2]

assert [3,3,3] == a + b 

解决方案
I wouldn't recommend globally overriding well-established behaviors. But, if you insist, this will do as you ask:
ArrayList.metaClass.plus << {Collection b -> 
    [delegate, b].transpose().collect{x, y -> x+y}
}
A more localized alternative would be to use a category:
class PlusCategory{
    public static Collection plus(Collection a, Collection b){
        [a, b].transpose().collect{x, y -> x+y}
    }
}
use (PlusCategory){
    assert [3, 3, 3] == [1, 1, 1] + [2, 2, 2]
}
However, I would probably create a generic zipWith method (as in functional programming), allowing one to easily specify different behaviors...
Collection.metaClass.zipWith = {Collection b, Closure c -> 
    [delegate, b].transpose().collect(c)
}
assert [3, 3, 3] == [1, 1, 1].zipWith([2, 2, 2]){a, b -> a+b}
assert [2, 2, 2] == [1, 1, 1].zipWith([2, 2, 2]){a, b -> a*b}


                        
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