Almost Rubinius

almost_rbx.rb

module Rules
class Processor
  def initialize(context)
    require 'parser/current'
    @context = context
  end

  def process(command)
    node = node_for_command(command)
    process_node(node)
  end

  def node_for_command(command)
    Parser::CurrentRuby.parse(command)
  end

  private
  attr_reader :context

  def process_node(node)
    raise "object is not a AST::Node" unless node.is_a?(Parser::AST::Node)

    node = clean_begin(node)
    children = node.children

    case node.type
    when :int
      children.first
    when :str
      children.first.to_s
    when :float
      children.first
    when :true
      true
    when :false
      false
    when :sym
      children.first
    when :nil
      nil
    when :send
      receiver = children.first.nil? ? context : process_node(children.first)
      method_name = children[1]
      args = children[2..-1].map{|arg| process_node(arg)}
      receiver.send(method_name, *args)
    when :or
      process_node(children.first) || process_node(children.last)
    when :and
      process_node(children.first) && process_node(children.last)
    when :dstr
      children.map{|child| process_node(child)}.join
    else
      raise "Found another type of node! #{node.type}"
    end
  end

  def clean_begin(node)
    return node unless node.type == :begin
    raise "begin has more than one children!" if node.children.length > 1
    node.children.first
  end
end
end