xml_builder.rb

class XMLBuilder

  def initialize
    @d = {}
  end

  def to_xml
    @d
  end

  def tag tag_name, content
    "<#{tag_name}>#{content}</#{tag_name}>"
  end

  def tag1 &blk
    parent_st = caller.find_all do |s|
      (s =~ /#{__FILE__}/) && 
      (s =~ /:in `tag.*?'$/)
    end
    parents = parent_st.map { |s| s.match(/`(tag.*?)'$/)[1] }
    @d[__callee__] = {parent: parents.first}
    @d[parents.first].merge children
    blk.call
  end

  def tag2 &blk
    parent_st = caller.find_all do |s|
      (s =~ /#{__FILE__}/) && 
      (s =~ /:in `tag.*?'$/)
    end
    parents = parent_st.map { |s| s.match(/`(tag.*?)'$/)[1] }
    @d[__callee__] = {parent: parents.first}
    blk.call
  end

  def tag3 &blk
    parent_st = caller.find_all do |s|
      (s =~ /#{__FILE__}/) && 
      (s =~ /:in `tag.*?'$/)
    end
    parents = parent_st.map { |s| s.match(/`(tag.*?)'$/)[1] }
    @d[__callee__] = {parent: parents.first}
    blk.call
  end

  def tag4 &blk
    parent_st = caller.find_all do |s|
      (s =~ /#{__FILE__}/) && 
      (s =~ /:in `tag.*?'$/)
    end
    parents = parent_st.map { |s| s.match(/`(tag.*?)'$/)[1] }
    @d[__callee__] = {parent: parents.first}
    blk.call
  end

end




xb = XMLBuilder.new
xb.tag1 do
  xb.tag2 do
  end
  xb.tag3 do
    xb.tag4 { 'hi hello' }
  end
end

puts xb.to_xml