# File lib/nanoc/extra/validators/w3c.rb, line 21
    def run
      # Load validator
      require 'w3c_validators'

      # Find all files
      filenames = []
      extensions = types_to_extensions(@types)
      extensions.each { |extension| filenames.concat(Dir[@dir + '/**/*.' + extension]) }

      # Validate each file
      filenames.each do |filename|
        validation_started(filename)

        extension = File.extname(filename)[1..-1]
        results = validator_for(extension).validate_file(filename)

        validation_ended(filename, results.errors)
      end
    end