How do I get access to an outer variable in a closure in ruby?

I have the following dynamically created class th开发者_StackOverflow社区at is passed into the xpath function of nokogiri:

country = nil

ret = parent.xpath(".//text()[regex(.)]", Class.new{
  def regex(node_set, lead)
    result = node_set.find_all do |node|
      node.text =~ POST_CODE_EXPRESSION || node.text =~ ZIP_CODE_EXPRESSION
    end
    result
  end
}.new)

I would like to somehow access or set the country variable or get access to the outer self from within the regex function.

Is there anyway I can pass the outer self into the Class.new expression or can anyone suggest a better way?

Methods cannot be closures in Ruby, only blocks can:

country = nil

ret = parent.xpath(".//text()[regex(.)]", Class.new{
  define_method(:regex) do |node_set, lead|
    result = node_set.find_all do |node|
      node.text =~ POST_CODE_EXPRESSION || node.text =~ ZIP_CODE_EXPRESSION
    end
    result
  end
}.new)

By the way: your regex method is much more complicated than it needs to be. It's simply equivalent to

define_method(:regex) do |node_set, lead|
  node_set.find_all do |node|
    node.text =~ POST_CODE_EXPRESSION || node.text =~ ZIP_CODE_EXPRESSION
  end
end

You can do it like this:

x = 1
Class.new do
  def initialize(binding)
    eval 'x += 1', binding
  end
end.new binding
p x # will print 2

It doesn't look very nice with eval but it works=)