我的结论如下：

> rexml relaxng模式解析可能不起作用.代码说明它不完整
> rexml pull解析可能有效,但很难说
>上述两种都没有记录
>您应该使用真正的XML库,例如libxml

这是我的测试程序：test.rb

require 'rexml/validation/relaxng.rb'
require 'rexml/parsers/pullparser.rb'

# USAGE: ruby test.rb XML-FILE
xml = ARGV[0]

# schema must be a Relax NG XML (NOT compact / .rnc)
schema = File.new( "example.rng" )
validator = REXML::Validation::RelaxNG.new( schema )

# The structure the validator made,which should be a complex structure but isn't
validator.dump

xmlfile = File.new( xml )
parser = REXML::Parsers::PullParser.new( xmlfile )
while parser.has_next?
  # Returns an PullEvent
  e = parser.pull
  # puts "Event ",e.inspect
  validator.validate(e)
end

我制作了一些玩具示例XML文件和RNG文件,然后在OSX 10.5.x上试用了它
(打破长线以使其可读)：

$/usr/bin/ruby test.rb good.xml 
< S.1 #{doc},:end_document(  ) >
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rexml/
  validation/validation.rb:24:in `validate': Validation error.  Expected:
  :start_element( doc ) from < S.1 #:start_element( doc ),{head},{body},:end_element(  ),:end_document(  ) >  but got "doc"(  )
  (REXML::Validation::ValidationException)
        from test.rb:20

(我和1.9一样)

所以,几乎失败了.

(我可以更多地优化测试程序以使用add_listener,但它似乎不值得)