gistfile1.rb

class Array
  
  def adjoin(*args)
    options = args.last.is_a?(Hash) ? args.pop : {}
    separators = args
    raise ArgumentError unless length == separators.length + 1
    prefix = first.dup
    separators.each_with_index do |separator, index|
      suffix = at(index + 1)
      prefix << separator if prefix.present? && suffix.present?
      prefix << suffix    if suffix.present?
    end
    prefix = options.delete :default_if_blank if prefix.blank?
    prefix
  end

end