Ruby中没有参数的DSL块 [英] DSL block without argument in ruby

问题描述

我正在用ruby写一个简单的dsl.几周前，我偶然发现了一些博客文章，其中展示了如何转换代码，例如:

I'm writing a simple dsl in ruby. Few weeks ago I stumbled upon some blog post, which show how to transform code like:

some_method argument do |book|
  book.some_method_on_book
  book.some_other_method_on_book :with => argument
end

输入清洁代码:

some_method argument do
   some_method_on_book
   some_other_method_on_book :with => argument
end

我不记得该怎么做，我不确定有什么缺点，但是更简洁的语法很诱人.有没有人知道这种转变的线索?

I can't remember how to do this and I'm not sure about downsides but cleaner syntax is tempting. Does anyone have a clue about this transformation?

推荐答案

def some_method argument, &blk
  #...
  book.instance_eval &blk
  #...
end

更新:但是，这省略了本书，但不允许您使用该参数.要透明地使用它，您必须以某种方式运输它.我建议自己在书上这样做:

UPDATE: However, that omits book but don't let you use the argument. To use it transparently you must transport it someway. I suggest to do it on book itself:

class Book
  attr_accessor :argument
end

def some_method argument, &blk
  #...
  book.argument = argument
  book.instance_eval &blk
  #...
end

some_method 'argument' do
   some_method_on_book
   some_other_method_on_book argument
end

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