具有多个隐式参数的函数字面量 [英] Function literal with multiple implicit arguments

问题描述

如何在 Scala 中定义具有多个隐式参数的函数字面量?我试过这种方式:

How to define function literal with multiple implicit arguments in Scala? I've tried this way:

def create = authAction { (implicit request, user) ⇒ // Syntax error
  Ok(html.user.create(registrationForm))
}

但它会引发编译错误.

推荐答案

如之前的回答所述，您只能为函数字面量定义一个隐式参数，但有解决方法.

As stated in previous answer, you can only define a single implicit parameter for a function literal, but there is workaround.

代替多个隐式参数，您可以将函数字面量写为采用多个参数列表，每个参数列表.然后可以将每个参数标记为隐式.重写原始片段:

Instead of multiple implicit arguments you can write function literal as taking multiple argument lists with one argument each. Then it is possible to mark each argument as implicit. Rewriting original snippet:

def create = authAction { implicit request ⇒ implicit user ⇒
  Ok(html.user.create(registrationForm))
}

您可以从 authAction 调用它作为 f(request)(user).

You can call it from authAction as f(request)(user).

implicit 关键字重复很烦人，但至少它有效.

implicit keyword duplication is annoying, but at least it works.

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