Selector-Free Cucumber Scenarios (from: http://bjeanes.com/2010/09/19/selector-free-cucumber-scenarios)

selectors.rb

# I'm in features/support/selectors.rb

module HtmlSelectorsHelper
  def selector_for(scope)
    case scope
    when /the body/
      "html > body"
    else
      begin
         scope =~ /the (.*)/
         components = $1.split(/\s+/)
         selector = "//*[@id='#{components.join('_')}']"
         page.find(:xpath, selector)
         selector
       rescue Object => e
         raise "Can't find mapping from \"#{scope}\" to a selector.\n" +
           "Now, go and add a mapping in #{__FILE__}"
       end
    end
  end
end

World(HtmlSelectorsHelper)

web_ext_steps.rb

# I'm in features/step_definitions/web_ext_steps.rb

When /^(.*) within ([^:"]+)$/ do |step, scope|
  with_scope(selector_for(scope)) do
    When step
  end
end

# Multi-line version of above
When /^(.*) within ([^:"]+):$/ do |step, scope, table_or_string|
  with_scope(selector_for(scope)) do
    When "#{step}:", table_or_string
  end
end