From: Steven Hahn <steverhahn@...>
Date: 2008-06-03T04:56:19+09:00
Subject: Re: [QUIZ] Price Ranges (#164)

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I had not created a SAX listener before in Ruby.  So, my solution reads the=
 vendor list in from XML.  I noticed others were using this pastie thingy..=
. I don't know what that is.  Besides, pasties always seemed to be kind of =
pointless to me.  They leave precious little to the imagination.  So, below=
 is the ruby file followed by the xml file:

---------------------------------------------------------------------------=
------
#!/usr/local/bin/ruby -w
require 'rexml/parsers/sax2parser'
require 'rexml/sax2listener'

class VendorListener
  include REXML::SAX2Listener

  def initialize(low, high)
    begin
      @low =3D Float(low)
    rescue
      @low =3D 0
    end
   =20
    begin
      @high =3D Float(high)
    rescue
      #if someone can spend more than this then
      #they can afford a better program
      @high =3D 10**15
    end
  end
 =20
  def start_element(uri, localname, tag_name, attrs)
    if tag_name =3D=3D 'Vendor'
      @vendorName =3D attrs['name']
    end
  end

  def end_element(uri, localname, tag_name)
    if tag_name =3D=3D 'Vendor'
      if in_range?
        puts @vendorName
      end
    elsif tag_name =3D=3D 'LowPrice'
      @lowPrice =3D Float(@data)
    elsif tag_name =3D=3D 'HighPrice'
      @highPrice =3D Float(@data)
    end
  end

  def characters(value)
    @data =3D value
  end

  def in_range?
    (@low >=3D @lowPrice and @low <=3D @highPrice) or
      (@high >=3D @lowPrice and @high <=3D @highPrice) or
      (@low < @lowPrice and @high > @highPrice)
  end
end

puts "Enter a price range."
print "Enter low value: "
low =3D gets
print "Enter high value: "
high =3D gets

parser =3D REXML::Parsers::SAX2Parser.new(File.new('vendors.xml' ))
parser.listen(VendorListener.new(low, high))
parser.parse

puts "Program terminated."
---------------------------------------------------------------------------=
------
<?xml version=3D"1.0" encoding=3D"UTF-8"?>
<Vendors>
    <Vendor name=3D"Company A">
        <PriceRange>
            <LowPrice>1000</LowPrice>
            <HighPrice>3000</HighPrice>
        </PriceRange>
    </Vendor>
    <Vendor name=3D"Company B">
        <PriceRange>
            <LowPrice>6000</LowPrice>
            <HighPrice>10000</HighPrice>
        </PriceRange>
    </Vendor>
    <Vendor name=3D"Company C">
        <PriceRange>
            <LowPrice>500</LowPrice>
            <HighPrice>2500</HighPrice>
        </PriceRange>
    </Vendor>
</Vendors>


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