From: stefano <scobianchi@...>
Date: 2004-03-21T19:49:30+09:00
Subject: Re: REXML concatenation

On Sat, 20 Mar 2004 00:12:25 +0900, Andrew Kulinich wrote:

> I have some xml documents:
> 1) <a><b><c id='1'/></b></a>
> 2) <a><b><c id='2'/></b></a>
> 3) <a><d><c id='3'/></d></a>
> 
> I want to concatenate them to get
> <a>
>    <b>
>      <c id='1'/>
>      <c id='2'/>
>    </b>
>    <d>
>      <c id='3'/>
>    </d>
> </a>
> 
> How can I make this using REXML?

A bit clumsy, but it works (at least with the given example :-)

require "rexml/document"

class REXML::Element
  def same_as?(other)
    self.name == other.name and
    self.attribute("id") == other.attribute("id")
  end

  def merge(other)
    if other.name == self.name
      other.each_element do |child|
        _merge(child)
      end
    end
  end

  def _merge(other)
    if other.is_a?(REXML::Element)
      if matching_node = REXML::XPath.first(self, other.name)
        if matching_node.same_as?(other)
          matching_node.merge(other)
        else
          add_element(other)
        end
      else
        add_element(other)
      end
    end
  end
end

doc1 = REXML::Document.new("<a><b><c id='1'/></b></a>")
doc2 = REXML::Document.new("<a><b><c id='2'/></b></a>")
doc3 = REXML::Document.new("<a><d><c id='3'/></d></a>")

doc = REXML::Document.new("<a/>")
doc.merge(doc1)
doc.merge(doc2)
doc.merge(doc3)

puts doc.to_s

=> <a><b><c id='1'/><c id='2'/></b><d><c id='3'/></d></a>


-- 
ste