class Addressable::Template

def join_values(operator, return_value)
  leader = LEADERS.fetch(operator, '')
  joiner = JOINERS.fetch(operator, ',')
  case operator
  when '&', '?'
    leader + return_value.map{|k,v|
      if v.is_a?(Array) && v.first =~ /=/
        v.join(joiner)
      elsif v.is_a?(Array)
        v.map{|inner_value| "#{k}=#{inner_value}"}.join(joiner)
      else
        "#{k}=#{v}"
      end
    }.join(joiner)
  when ';'
    return_value.map{|k,v|
      if v.is_a?(Array) && v.first =~ /=/
        ';' + v.join(";")
      elsif v.is_a?(Array)
        ';' + v.map{|inner_value| "#{k}=#{inner_value}"}.join(";")
      else
        v && v != '' ?  ";#{k}=#{v}" : ";#{k}"
      end
    }.join
  else
    leader + return_value.map{|k,v| v}.join(joiner)
  end
end