Despite the fact that XML attributs can be defined using single or double quotes, my user is trying to integrate my software with another one that will not accept single quo
As of Feb 2007 there's a supported way of determining the quoting character. The changes were merged into Ruby sources on Jul 2007 and should be available on all versions since 1.8.6-p110:
require 'rexml/document'
doc = REXML::Document.new
doc.context[:attribute_quote] = :quote # <-- Set double-quote as the attribute value delimiter
root = doc.add_element('root')
root.add_attribute('val', '123')
doc.write(STDOUT)
Running that yields:
$ ruby test.rb
$