do..end对Ruby的大括号 [英] do..end vs curly braces for blocks in Ruby

问题描述

我有一个同事正在积极地试图说服我，我不应该使用do..end，而是使用花括号来定义Ruby中的多行块。

I have a coworker who is actively trying to convince me that I should not use do..end and instead use curly braces for defining multiline blocks in Ruby.

我坚定地在营地只使用大括号短的一线和do..end为一切。但我想我会联系更大的社区得到一些解决方案。

I'm firmly in the camp of only using curly braces for short one-liners and do..end for everything else. But I thought I would reach out to the greater community to get some resolution.

那是什么，为什么呢？ （一些代码的示例）

So which is it, and why? (Example of some shoulda code)

context do
  setup { do_some_setup() }
  should "do somthing" do
    # some more code...
  end
end

或

context {
  setup { do_some_setup() }
  should("do somthing") {
    # some more code...
  }
}

推荐答案

puts [1,2,3].map{ |k| k+1 }
2
3
4
=> nil
puts [1,2,3].map do |k| k+1; end
#<Enumerator:0x0000010a06d140>
=> nil

这意味着{}具有比do..end更高的优先级，

This means that {} has a higher precedence than do..end, so keep that in mind when deciding what you want to use.

PS：在开发您的偏好设置时，还要记住一个例子。

P.S: One more example to keep in mind while you develop your preferences.

以下代码：

task :rake => pre_rake_task do
  something
end

真的意味着：

task(:rake => pre_rake_task){ something }

此代码：

task :rake => pre_rake_task {
  something
}

真的意味着：

task :rake => (pre_rake_task { something })

为了获得所需的实际定义，使用大括号必须执行：

So to get the actual definition that you want, with curly braces, you must do:

task(:rake => pre_rake_task) {
  something
}

也许使用大括号是参数是你想做的反正，但如果你不这样做最好使用在这些情况下，避免这种混乱。

Maybe using braces for parameters is something you want to do anyways, but if you don't it's probably best to use do..end in these cases to avoid this confusion.

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