这些奇怪的角色是什么意思?

I'm reading a Ruby book but it doesn't explain the following:

我正在读一本Ruby的书，但它没有解释以下内容:

1. What is this: validates :name, :presence => true

   什么是:validates:name:presence => true

   • I mean I know what it does but what's validates? Is it a method of the validator class? If so, how come it's called without mentioning the class name first?

     我的意思是我知道它的作用但是什么是有效的?它是validator类的一个方法吗?如果是，为什么不先提到类名就调用它呢?

   • What's the meaning of : in the previous code and in Rails on general?

     在以前的代码和Rails中，一般来说是什么意思?

2. In the following code: <%= form_for([@post, @post.comments.build]) do |f| %>

   在以下代码中:<%= form_for([@post， @post.comments.build]) |f| %>。

   • Is form_for an object or a procedural function?

     form_for是对象还是过程函数?

   • What's the meaning of the | character in |f|

     |f|中的|字符是什么意思

3. In <%= link_to 'Edit Post', edit_post_path(@post) %>

   在<%= link_to 'Edit Post'中，edit_post_path(@post) %>

   • Who, where and when was edit_post_path method defined?

     edit_post_path方法定义了谁、在何处以及何时?

   • To which class it belongs?

     它属于哪个类别?

1 个解决方案

#1

1. validates is a method, part of the validators in Rails. It is declared in (actually, included to) a superclass, that is why it does not have to be declared in the model. The : in front of anything signifies a symbol, not a variable. Symbols are part of Ruby, somewhat similar to strings.
2. 验证是一个方法，是Rails中的验证器的一部分。它被声明在超类中(实际上包括在超类中)，这就是为什么它不必在模型中声明的原因。在任何东西前面都表示符号，而不是变量。符号是Ruby的一部分，有点类似于字符串。
3. form_for is a method, which takes a number of parameters and a block (that is why there is a do afterwards). The | is part of Ruby syntax, the way you enclose code block parameters.
4. form_for是一个方法，它接受许多参数和一个块(这就是为什么后面会有一个do)。|是Ruby语法的一部分，是封装代码块参数的方式。
5. edit_post_path is defined by the Rails magic and the routes. It is a helper method.
6. edit_post_path由Rails魔法和路由定义。它是一个辅助方法。

I encourage you to read this book about Ruby to get more familiar with symbols, code blocks, modules and other things that make Ruby a great programming language.

我鼓励您阅读这本关于Ruby的书，以便更熟悉符号、代码块、模块和其他使Ruby成为优秀编程语言的东西。