具有多个隐式参数的函数文字 [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

如上一个答案所述，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.

您可以将函数文字编写为采用多个参数列表，每个列表带有一个参数，而不是多个隐式参数.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，但至少可以.

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

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