From: Xeno Campanoli / Eskimo North and Gmail <xeno.campanoli@...>
Date: 2010-07-17T07:52:37+09:00
Subject: Re: Hpricot test for equivalence of two xml segments?

On 10-07-16 03:16 PM, Ammar Ali wrote:
> On Sat, Jul 17, 2010 at 12:28 AM, Xeno Campanoli / Eskimo North and Gmail<
> xeno.campanoli@gmail.com>  wrote:
>
>> I'm looking through what documentation I can find for Hpricot (nokogirl
>> wouldn't install for me, and I just wand a quick an simple solution), and I
>> cannot find a simple method to take two xml strings and find out if they are
>> equivalent.  I'm getting a bunch of xhmtl back from our rendering agent with
>> random permutations of attributes inside of the tags, and I want a quick and
>> easy ruby way to find out of segments are equivalent without writing my own
>> regex based parser...???
>
>
> I can think of a few definitions for equivalence. One definition would
> simply require unifying the case of both strings and checking if they are
> the same. A second definition would require building a tree of the structure
> in each string, including attributes, sorting it, and looping over them to
> check if they contain the same elements (Nokogiri's XML::NodeSet does
> something like this with ==). A third definition would build on the second
> one, while treating certain tags as equivalent to other tags (for example q
> is equivalent to blockquote).
>
> What's *your* definition of equivalence for two xml documents or fragments?
>
> Ammar

The only thing I am concerned about is permutations of attributes inside the 
tags.  Everything else I'm seeing is regular.  Is there something where I can 
parse all the tags in a segment and tell if they are equivalent and just have 
the attributes in different orders?  I'm not even concerned about different tag 
forms.  We don't see that.  A typical example is:

< <li><img src="/my/image/path/thingy.jpg" alt="alt text" />My Text</li>
 > <li><img alt="alt text" src="/my/image/path/thingy.jpg" />My Text</li>

I need to have something that can help me judge such things as equivalent. 
Again, I NEVER see tag permutations, but just attribute permutations.
>

Thank you for you response.

Sincerely, Xeno

-- 
"It's the preponderance, stupid!" - Professor Stephen Schneider, IPCC member