具有多个参数的Scala隐式转换 [英] Scala implicit conversions with multiple arguments

问题描述

我一直认为Scala隐式转换只能使用一个参数，如果需要从多个参数进行转换之类的东西，则可以使用元组.但是，我惊讶地发现Scala 2.10.3实际上接受了这个(傻)定义，没有问题:

I've always thought that Scala implicit conversions could only take one argument, and if you needed something like conversion from multiple arguments, you would use a tuple. However, I was surprised to find that Scala 2.10.3 actually accepts this (silly) definition without problem:

scala> implicit def foo(i: Int, j: Int): Int = i
foo: (i: Int, j: Int)Int

是否有任何方式或理由使用这种多参数隐式?

Is there any way or reason to use such a multi-argument implicit?

推荐答案

并非所有隐式函数都是转换！

Not all implicit functions are conversions!

任何具有单个参数 的隐式函数都可以用作转换，但这不是唯一的隐式用例.

Any implicit function with a single argument could be used as a conversion, but that's not the only use-case for implicits.

函数只是另一种类型，因此，您可以在(implicit fn:(Int，Int)=> Int)

Functions are just another type and, as such, you can specify an implicit argument as in (implicit fn: (Int, Int) => Int)

但是我不会这样做，您打算以隐式形式传递的任何内容都应具有一个 far 更具体的类型，以便更好地自我记录其预期目的.

I wouldn't do this though, anything you intend to pass as an implicit should have a far more specific type that better self-documents its intended purpose.

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