红宝石中未定义的方法错误NoMethodError

Question

以下代码返回错误，但我不知道为什么：

require "rexml/document"
include REXML

file = File.new("test.xml")
doc = REXML::Document.new file

 class Registration
     attr_accessor :number, :jurisdiction, :physicallyPresentInRegistrationCountry
 end 

 def constructRegistration(item, typeOfMerchant)
    reg = Registration.new
    element = item.elements[typeOfMerchant + "PhysicallyPresentInRegistrationCountry"]
    if element != nil then
        reg,physicallyPresentInRegistrationCountry = element.text
    else
        reg.physicallyPresentInRegistrationCountry = nil
    end 
    return reg
  end

  XPath.each(doc, "//transactionAuditRecordList/item") { |item|
     reg = constructRegistration(item, "seller")
     puts reg.physicallyPresentInRegistrationCountry    
  }  

rexml.rb：26：未定义的方法“ physicallyPresentInRegistrationCountry”为“ false”：字符串（NoMethodError）

    from /usr/lib/ruby/1.8/rexml/xpath.rb:53:in `each'

    from /usr/lib/ruby/1.8/rexml/xpath.rb:53:in `each'

    from rexml.rb:24

Answer 1

看起来像是一个逗号，而不是一个点：

if element != nil then
    reg,physicallyPresentInRegistrationCountry = element.text
#----^^^^

这具有对两个vars reg和physicallyPresentInRegistrationCountry进行多重分配的效果，但是=右侧的一个表达式表示

reg = element.text
physicallyPresentInRegistrationCountry = nil