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How to use classes in shoes?

I am a beginner programmer who has experience with processing. I am currently trying to make an application using Shoes, but I am confused about how objects and classes work.

I understand that the following will do the following in Ruby:

class Post
    def self.print_author
      puts "The author of all posts is Jimmy"
    end
end

Post.print_author

But why isn't the following in the shoes? How can I start it?

class Post
    def self.print_author
      para "The author of all posts is Jimmy"
    end
end

Shoes.app do
    Post.print_author
end
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2 answers


I'm not very familiar with Shoes, but the problem you are probably running into is that you are trying to call a method para

in a class Post

and no such method exists.

When you call Shoes.app do ...

, I suspect that Shoes is changing the current execution context to one that includes these methods. That is, you should expect this to work:

Shoes.app do
  para "The author of all posts is Jimmy"
end

This is equivalent to:



Shoes.app do
  self.para("The author of all posts is Jimmy")
end

When you call Post.print_author

, it is self

no longer a Shoes object, but rather a Post class. At this point, you have several options:

  • Go to the Shoes instance and call your shoe-specific methods on it. You should probably do it this way when you don't need any state from the Post:

    class Post
  def self.print_author(shoes)
    shoes.para "The author of all posts is Jimmy"
  end
end

Shoes.app do
  Post.print_author(self)
end

  • Create a Post class that accepts a Shoes object so you don't need to skip it. You should do it this way if the Post will have a significant number of states:

    class Post
  def initialize(shoes)
    @shoes = shoes
  end

  def print_author
    @shoes.para "The author of all posts is Jimmy"
  end
end

Shoes.app do
  post = Post.new(self)
  post.print_author
end

  • You can use the option on option 2. to automatically transfer calls to the object @shoes

    . This is starting to creep into Ruby metaprogramming, which I would recommend that you avoid until you are more comfortable with Ruby, but I leave it here to keep you interested:

    class Post
  def initialize(shoes)
    @shoes = shoes
  end

  def print_author
    para "The author of all posts is Jimmy"
  end

  def method_missing(method, *args, &block)
    @shoes.send(method, *args, &block)
  end
end

Shoes.app do
  post = Post.new(self)
  post.print_author
end

What it means is Ruby says "if the method is not found on the Post instance, try submitting it instead of the @shoes instance." As you can imagine, some very nice DSLs can afford this, but you must use them carefully as it can make your code difficult to execute if you overuse it.

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An easier way to do this is to Post

provide content and then display that content in your Shoes application, but you want it. Side benefit: you can reuse the Post class in another class that prints to the console.



class Post
  def self.print_author
    "The author of all posts is Jimmy"
  end
end

Shoes.app do
  para Post.print_author
end

class ConsoleApp
  def run
    puts Post.print_author
  end
end
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