basic query parsing

  X_VALIDATE = /^(([a-z]+\([^\)]*\)) *)+$/

  X_EXTRACT  = /(([a-z]+)\(([^\)]*)\))/

  FUNCTIONS  = %w(filter since until stream)

  attr_accessor :since, :until, :filters

  def initialize(str)

    @filters = []

    unless str.match(X_VALIDATE)

  	  raise InvalidQueryError.new("Invalid Query: #{str}") 

      raise InvalidQueryError.new("invalid query: #{str}") 

    end

    str.scan(X_EXTRACT) do |part|

      eval_part(*part[1..-1])

    end

  end

private

  def eval_part(func, arg) 

    unless FUNCTIONS.include?(func)

      raise InvalidQueryError.new("unknown function: ... #{func}(#{arg}) ...") 

    end

    send("eval_#{func}", arg)

  end

  def eval_stream(arg)

    unless arg == ""

      raise InvalidQueryError.new("too many arguments: ... stream(#{arg}) ...") 

    end

    unless @until.nil?

      raise InvalidQueryError.new("until specified twice: ... stream(#{arg}) ...")  

    end

    @until = :stream

  end

  def eval_since(arg)

    unless @since.nil?

      raise InvalidQueryError.new("since specified twice: ... since(#{arg}) ...")  

    end

    @since = parse_time(arg)

  end

  def eval_until(arg)

    unless @until.nil?

      raise InvalidQueryError.new("since specified twice: ... until(#{arg}) ...")  

    end

    @until = parse_time(arg)

  end

  def parse_time(str)

    str.to_i # FIXPAUL validate

  end

end  

        puts e.to_s

        exit!(1)

      end

      puts query.inspect

    end

  end