From: Marc-antoine Kruzik <kadelfek@...>
Date: 2009-09-07T17:10:07+09:00
Subject: Re: something.new( :attribute => value) thing

Martin Boese wrote:
> On Sun, 2009-09-06 at 03:06 +0900, Marc-antoine Kruzik wrote:
>> >    A.send(:attr_accessor, key)
>> >    send("#{key}=", val)
>> 
>> This solution is what I was looking for.
>> With a bit of work, I will be able to write code like this :
> 
> Hi Marc,
> 
> I'd try to keep it simple:
> 
> class A
>  def initialize(param_a, param_b, options = {})
>     @x = options[:x] || 50     # defaults to 50 if not specified
>     @y = options[:y] || 100
>     @z = options[:z] || 'red'
>     puts "Initialized with #{@x}/#{@y}/#{@z}"
>  end
> end

Use default values is a goog idea. The problem is, you have to write the 
code for @x, @y and @z.


My version is now this one :

I have three classes :
GUI_Object > GUI_Object_Graphic > Picture

The purpose of the code is to avoid to write a lot of code when you are 
working on classes like Picture.

(I know, I don't optimize my code, if you have better solution, it would 
be nice.)


class GUI_Object

  attr_accessor :parent

  @accessors = [:parent]


  def initialize(parent=nil, hash=nil)

    @parent = parent

    hash = param_hash_1(parent, hash)
    modify_accessor(hash)

  end

  def param_hash_1(parent, hash)
    if hash.is_a?(Hash)
      return hash
    elsif parent.is_a?(Hash)
      @parent = nil
      return parent
    end
    return nil
  end

  def modify_accessor(hash)
    return if hash == nil
    hash.each do |key, val|
      if self.class.check_accessor(key) == true
        # Here's the 7stud function :
        send("#{key}=", val)
      else
        raise("unknown accessor for class #{self.class}: #{key}")
      end
    end
  end

  def self.check_accessor(acc)
    if self.accessor != nil and self.accessor.include?(acc)
        return true
    else
      if self != GUI_Object
        return true if self.ancestors[1].check_accessor(acc) == true
      end
    end
    return false
  end

  def self.accessor
    return @accessors
  end


end



class GUI_Object_Graphic < GUI_Object

  attr_reader   :x
  attr_reader   :y
  attr_accessor :width
  attr_accessor :height

  @accessors = [:x, :y, :width, :height]


  def initialize(parent=nil, x=0, y=0, width=0, height=0, hash=nil)

    @x = x
    @y = y
    @width = width
    @height = height
    hash = param_hash(x, y, width, height, hash)

    @x = 0 if @x == nil
    @y = 0 if @y == nil
    @width = 0 if @width == nil
    @height = 0 if @height == nil

    super(parent, hash)

  end


  def param_hash(x, y, width, height, hash)
    if hash.is_a?(Hash)
      return hash
    elsif x.is_a?(Hash)
      @x = 0
      return x
    elsif y.is_a?(Hash)
      @y = 0
      return y
    elsif width.is_a?(Hash)
      @width = 0
      return width
    elsif height.is_a?(Hash)
      @height = 0
      return height
    end
    return nil
  end

end



class Picture < GUI_Object_Graphic

  attr_accessor :bg_color
  attr_accessor :cadre
  attr_accessor :marges
  attr_accessor :image
  attr_accessor :zoom


  # I ONLY have to create THIS list to use the attributes I want
  @accessors = [:bg_color, :picture, :zoom]
  # So, it's really, really not difficult


  def initialize(parent=nil, x=0, y=0, width=0, height=0, hash=nil)

    # Default values
    @bg_color = nil
    @zoom = 1


    super

    @marges = [0, 0, 0, 0]
    @cadre = nil

  end

end



So I can use these codes to create a Picture :

x = y = width = height = 0

a = Picture.new(nil, x, y, width, height)
a = Picture.new(nil, x, y, :zoom => 2, :width => 30, :bg_color => "red")


I'm not using a class variable like @@accessors, because of the problems 
with class variables.

With this code, people can easily create new classes like Picture. And 
with a simple list like @accessors = [:bg_color, :picture, :zoom], they 
can allow to use only the attributes they want.


It's part of my code to create a super-easy-to-use GUI working with a 
video game graphical library.
Here's a screenshot :
http://i291.photobucket.com/albums/ll318/KingKadelfek/screen05-f95306.png

I want the users able to create new components (such as Picture), so I 
try to find the most easiest way.
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