Contents

module Visitor
  def visit(obj)
    method = _visitor_method(obj)
    self.send(method, obj) if method
  end

  def visit_me_and_my_children(me, children)
    visit(me)
    children.each {|c| c.accept_visitor(self)}
  end

  def visit_me_then_children(obj, *children)
    visit(obj)
    children.each {|cs| cs.each {|c| c.accept_visitor(self)}}
  end

  # Find the visit_X method to use based on the inheritance tree. First try
  # the class name then traverse the ancestors list.
  def _visitor_method(obj)
    obj.class.ancestors.map {|c| _visitor_method_for_class(c)}.compact.first
  end

  def _visitor_method_for_class(klass)
    _visitor_methods[klass] ||= _methodname_from_class(klass)
  end
  
  def _visitor_methods
    @_visitor_methods ||= Hash.new
  end

  def _methodname_from_class(klass)
    name = "visit_" + klass.inspect.split("::").last
    self.class.instance_methods.include?(name) ? name : nil
  end

  def visit_each(ary)
    ary.each {|e| e.accept_visitor(self)}
  end
end

module Visitable
  def accept_visitor(visitor)
    visitor.visit(self)
  end
end

class Object
  include Visitable
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
rockit-0.7.1	lib/util/visitor.rb