rails源码ActionSupport（待续）

一些奇淫技巧

class Object

  # An elegant way to factor duplication out of options passed to a series of
  # method calls. Each method called in the block, with the block variable as
  # the receiver, will have its options merged with the default +options+ hash
  # provided. Each method called on the block variable must take an options
  # hash as its final argument.
  # 
  #   with_options :order => 'created_at', :class_name => 'Comment' do |post|
  #     post.has_many :comments, :conditions => ['approved = ?', true], :dependent => :delete_all
  #     post.has_many :unapproved_comments, :conditions => ['approved = ?', false]
  #     post.has_many :all_comments
  #   end
  #
  # Can also be used with an explicit receiver:
  #
  #   map.with_options :controller => "people" do |people|
  #     people.connect "/people",     :action => "index"
  #     people.connect "/people/:id", :action => "show"
  #   end
  #
  def with_options(options)
    yield ActiveSupport::OptionMerger.new(self, options)
  end

module ActiveSupport
  class OptionMerger #:nodoc:
    instance_methods.each do |method|
      undef_method(method) if method !~ /^(__|instance_eval|class|object_id)/
    end

    def initialize(context, options)
      @context, @options = context, options
    end

    private
      def method_missing(method, *arguments, &block)
        if arguments.last.is_a?(Proc)
          proc = arguments.pop
          arguments << lambda { |*args| @options.deep_merge(proc.call(*args)) }
        else
          arguments << (arguments.last.respond_to?(:to_hash) ? @options.deep_merge(arguments.pop) : @options.dup)
        end

        @context.__send__(method, *arguments, &block)
      end
  end
end

引用

   instance_methods.each do |method|
      undef_method(method) if method !~ /^(__|instance_eval|class|object_id)/
    end

引用

      def method_missing(method, *arguments, &block)
        if arguments.last.is_a?(Proc)
          proc = arguments.pop
          arguments << lambda { |*args| @options.deep_merge(proc.call(*args)) }
        else
          arguments << (arguments.last.respond_to?(:to_hash) ? @options.deep_merge(arguments.pop) : @options.dup)
        end

        @context.__send__(method, *arguments, &block)
      end