From: Bob Hutchison <hutch@...>
Date: 2005-10-11T23:49:34+09:00
Subject: Re: help with htree

Hi,

Thanks for the pointer to HTree.

On Oct 10, 2005, at 5:31 PM, Ara.T.Howard wrote:

> On Tue, 11 Oct 2005, Ara.T.Howard wrote:
>
>
>>
>> i'm trying use the htree library for a relatively simple task in  
>> the hope that
>> it's parser will outlive one i roll on my own - it certainly seems  
>> robust as
>> it is...  in any case i'm trying to do the following
>>
>>  - scan a doc for any elements that have a certain attribute
>>  - iff the element with that attribute is of a certain class (b,  
>> i, pre, etc)
>>    then i'll want to replace the text of that element in-place
>>  - finally, a new doc will be produced
>>
>> any hints appreciated.  i've got a hand parsed version running now  
>> - but
>> really would like to use htree.
>>
>
> on a related note, does this seem right to people:
>
>   irb(main):019:0> HTree("<hr/>").display_html ''
>   => "<hr\n>"
>

HTML doesn't have an element <hr/> it has <hr>, like the old <p> tag.  
Though most browsers support it, though some will require <hr />  
(note the space). So, technically I suppose HTree is correct.

> notice it ate the closing slash.  i know that's bad form, but i  
> wonder if this
> is intended or not...
>

Give this code a shot, I think this is what you want assuming I read  
you correctly. Had to dump yaml a few times to figure out what was  
going on :-)

Cheers,
Bob

require 'htree'

def handle_element(elem)
   new_element_name = elem.element_name().to_s
   new_attributes = Hash.new().merge(elem.attributes)
   elem.attributes.each{ | name, value |
     if "replace" == name.to_s then
       new_element_name = value.to_s
       new_attributes.delete(name)
       break
     end
   }

   if (elem.kind_of?(HTree::Text))
     new_elem = elem.to_s
   elsif (elem.kind_of?(HTree::Elem))
     children = []
     elem.children.each(){ | child |
       if (child.kind_of?(HTree::Text)) then
         children << child.to_s
       elsif (child.kind_of?(HTree::Elem))
         children << handle_element(child)
       end
     }
     new_elem = HTree::Elem.new(new_element_name, new_attributes,  
children)
   end
   return new_elem
end

def handle_root(root)
   children = []
   root.children.each(){ | elem |
     children << handle_element(elem) if (elem.kind_of?(HTree::Elem))
   }
   HTree::Doc.new(children)
end

html = %Q{
<p>
<i replace='em'>hello</i> there, <b replace='strong'>how</b> are you?
</p>
}

tree = HTree(html)
new_tree = handle_root(tree)

puts tree.display_html("")
puts new_tree.display_html("")
__EOF__

----
Bob Hutchison          -- blogs at <http://www.recursive.ca/hutch/>
Recursive Design Inc.  -- <http://www.recursive.ca/>
Raconteur              -- <http://www.raconteur.info/>