#
# Ronin SQL - A Ruby DSL for crafting SQL Injections.
#
# Copyright (c) 2007-2013 Hal Brodigan (postmodern.mod3 at gmail.com)
#
# This file is part of Ronin SQL.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#

require 'ronin/sql/literals'
require 'ronin/sql/fields'
require 'ronin/sql/functions'
require 'ronin/sql/statement'
require 'ronin/sql/statements'
require 'ronin/sql/emittable'

module Ronin
  module SQL
    #
    # Represents a SQL Clause.
    #
    class Clause < Struct.new(:keyword,:argument)

      include Literals
      include Fields
      include Functions
      include Statements
      include Emittable

      #
      # Initializes the SQL clause.
      #
      # @param [Symbol] keyword
      #   The name of the clause.
      #
      # @param [Object] argument
      #   Additional argument for the clause.
      #
      # @yield [(clause)]
      #   If a block is given, the return value will be used as the argument.
      #
      # @yieldparam [Clause] clause
      #   If the block accepts an argument, it will be passed the new clause.
      #   Otherwise the block will be evaluated within the clause.
      #
      def initialize(keyword,argument=nil,&block)
        super(keyword,argument)

        if block
          self.argument = case block.arity
                          when 0 then instance_eval(&block)
                          else        block.call(self)
                          end
        end
      end

    end
  end
end