From: Micke Lax <mickelax@...>
Date: 2007-07-13T18:25:53+09:00
Subject: Help with passing a callback method

Hi!

I am trying to do the following. I can't get it to work, don't know if
it even is possible but it would be nice. If it is not possible to do it
the way I try here is there any other good approach?

My reason to use a callback is to keep the code size down and avoid
duplicate code. in one case I would use create_xml_str and in the other
case create_h_str

I have cut out a lot of code to keep the size down, tell me if you need
to see more.


###--------------------------------------------------------------------
### header_data.rb
###--------------------------------------------------------------------
class Header_Data
  def create_xml_str
  # returns a xml-formated string
  end

  def create_h_str
  # returns a h-formated string
  end

end


###--------------------------------------------------------------------
### header_data_array.rb
###--------------------------------------------------------------------
/.../
class Header_Data_Array

def interpret_layout(t, callback)
    result = String.new
    case
    when (t.match(/empty/))
      result = "\n\n"

    when (t.match(/^\d{1,4}/))
      a = @data_array[t.to_i]
      # here a tries to call the callback (crash...)
      a.callback.call()

    when (t.match(/[A-Z]*/))
      result =  create_subtitle_str(t)

    end
    return result
  end



  def create_file(file_name, layout)
    # get the callback and pass it in the method call
    function = Header_Data.new.method(:create_xml_string)
    layout   = layout.map{|l| interpret_layout(l, function)}

  end
/.../

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