# encoding: utf-8
require 'rubygems'
require 'sexp'

class Sexp
  def accept(visitor)
    visitor.visit(self)
  end

  def node_type
    first
  end

  def children
    find_all { | sexp | Sexp === sexp }
  end
  
  def is_language_node?
    first.class == Symbol
  end
  
  def visitable_children
    parent = is_language_node? ? sexp_body : self
    parent.children
  end
  
  def recursive_children(&handler)
    visitable_children.each do |child|
      handler.call child
      child.recursive_children(&handler)
    end
  end
  
  def grep_nodes(options)
    return self if options.empty?
    node_type = options[:node_type]
    subject = options[:subject]
    message = options[:message]
    arguments = options[:arguments]
    nodes = []
    self.recursive_children do |child|
      if (!node_type or node_type == child.node_type) and (!subject or subject == child.subject) and (!message or message == child.message) and (!arguments or arguments == child.arguments)
        nodes << child
      end
    end
    nodes
  end
  
  def subject
    if [:attrasgn, :call, :class, :iter].include? node_type
      self[1]
    end
  end

  def left_value
    if [:lasgn, :iasgn].include? node_type
      self[1]
    end
  end
  
  def message
    if [:attrasgn, :call, :defs, :iter].include? node_type
      self[2]
    end
  end
  
  def arguments
    if [:attrasgn, :call].include? node_type
      self[3]
    end
  end
  
  def call
    if [:if, :arglist].include? node_type
      self[1]
    end
  end
  
  def conditional_statement
    if node_type == :if
      self[1]
    end
  end
  
  def true_node
    if :if == node_type
      self[2]
    end
  end
  
  def false_node
    if :if == node_type
      self[3]
    end
  end

  def message_name
    if :defn == node_type
      self[1]
    end
  end
  
  def body
    if :block == node_type
      self[1..-1]
    elsif :class == node_type
      self[3]
    elsif :defn == node_type
      self[3][1]
    elsif :defs == node_type
      self[4][1]
    end
  end
  
  def to_s
    if [:lvar, :ivar].include? node_type
      self[1].to_s
    elsif :str == node_type
      self[1]
    elsif :lit == node_type
      ":#{self[1]}"
    elsif :array == node_type
      "[\"#{self.children.collect(&:to_s).join('", "')}\"]"
    elsif :hash == node_type
      key_value = false # false is key, true is value
      result = "{"
      children.each do |child|
        result += "#{child.to_s}#{key_value ? ', ' : ' => '}"
        key_value = !key_value
      end
      result.sub!(/, $/, '')
      result += "}"
    end
  end
  
  #def to_ruby
    #Ruby2Ruby.new.process(self) unless self.empty?
  #end
  
  #def to_ruby_string
    #return nil if self.empty?
    #eval(Ruby2Ruby.new.process(self)).to_s
  #end
end