Gavin Kistner
5/19/2005 2:46:00 PM
On May 19, 2005, at 8:15 AM, John Lam wrote:
> item.details = []
> doc.elements.each('ItemLookupResponse/Items/Item') do |item|
> # construct an item_detail
> item_details << item_detail
> end
>
> This doesn't *feel* right. I wanted to use collect() but it's not
> implemented in REXML. Is there a more Ruby-esque approach to gathering
> some objects into an array while parsing XML?
You seem to have left a detail out of your code (where does
'item_detail' come from?) but that's generally what I do in similar
circumstances.
Alternatively, you could write your own #collect method:
class REXML::Elements
def collect( xpath=nil )
vals = []
self.each(xpath){ |el| vals << yield el }
vals
end
end
Or, perhaps you could modify the existing each method to return an
array with no block supplied:
class REXML::Elements
alias_method :__each :each
def each( xpath=nil, &block )
if block_given?
__each( xpath, &block )
else
els = []
__each( xpath ){ |el| els << el }
els
end
end
end
Then you could simply:
item_details = doc.elements.each( '...' ).collect{ ... }
But then this is really exactly what Xpath.match does:
item_details = XPath.match( doc, 'ItemLookupResponse/Items/
Item' ).collect{ ... }
(Aside: What possessed the author of the REXML library to put all the
XPath stuff in its own class with class methods? Why not simply
"doc.match( my_xpath )"? Whenever I see a class method that takes a
single object for an argument to set scope, it screams to me that it
should be a method on that object.)
Hope that helps,
--
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