From: 7stud -- <bbxx789_05ss@...>
Date: 2009-03-19T04:23:37+09:00
Subject: Re: REXML get specific element

Phlip wrote:
>> You are missing the '-s.
>> Try
>> doc.root.elements["programmer[@name='#{entered_name}']"]
> 
> Then that croaks if the name contains an apostrophe.
> 
> Try (IIRC)...
> 
>    XPath.first(doc, '//programmer[ @name = $name ]', :name => 
> entered_name)

That doesn't work for me.  And I couldn't figure out the escaping 
necessary to handle both a name entered with a single quote or a double 
quote.  I thought I understood ruby escaping, but not anymore.

Here is the easy case:

1)
<xml version="1.0" encoding="ISO-8859-1"?>
<programmers>
        <programmer age="50">John</programmer>
        <programmer age="30">Sally</programmer>
</programmers>


require 'rexml/document'
include REXML

f = File.new('xml4.xml')
doc = Document.new(f)

input_name = gets
input_name = input_name.chomp

target = XPath.match(doc, "//programmer[text() = 'John']")
puts target[0].attributes["age"]

-------

$ ruby r1test.rb
John
50


Now suppose the programmer's name is Joh'n

<xml version="1.0" encoding="ISO-8859-1"?>
<programmers>
        <programmer age="50">Joh'n</programmer>
        <programmer age="30">Sally</programmer>
</programmers>


This is one of my favorite attempts to escape a single quote in the 
input name:

input_name = "Joh'n"
p input_name
input_name = input_name.gsub("'", "\\'")
p input_name

--output:--
"Joh'n"
"Johnn"

Can anyone explain what's going on there?
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