class AstRewritter
      def initialize(ast,interpretation_context) @ast = AbstractSyntaxTree.new(ast, interpretation_context)
@roles = interpretation_context.roles
 end
 def rewrite!() ast.each_production do |production|
  case production.type
  when Tokens.rolemethod_call then
    data = production.data
    production[2] = ((("self_" + data[1].to_s) + "_") + data[0].to_s).to_sym
    production[1] = nil
  when Tokens.block_with_bind then
    block = production.last
    block.delete_at(1)
    production.data.each do |local, aliased_role|
      must_b_sym = "aliased_role must be a Symbol".to_sym
      local_must_b_sym = "local must be a Symbol".to_sym
      raise(must_b_sym) unless aliased_role.instance_of?(Symbol)
      raise(local_must_b_sym) unless local.instance_of?(Symbol)
      unless @roles.has_key?(aliased_role) then
        role_names = []
        @interpretation_context.each { |k, v| (role_names << k.to_s) }
        raise(((aliased_role.to_s + " is not a role. Available roles are ") + role_names.join(",")))
      end
      aliased_field = ("@" + aliased_role.to_s).to_sym
      temp_symbol = ("temp____" + aliased_role.to_s).to_sym
      assignment = Sexp.new
      assignment[0] = :iasgn
      assignment[1] = aliased_field
      load_arg = Sexp.new
      load_arg[0] = :lvar
      load_arg[1] = local
      assignment[2] = load_arg
      block.insert(1, assignment)
      assignment = Sexp.new
      assignment[0] = :lasgn
      assignment[1] = temp_symbol
      load_field = Sexp.new
      load_field[0] = :ivar
      load_field[1] = aliased_field
      assignment[2] = load_field
      block.insert(1, assignment)
      assignment = Sexp.new
      assignment[0] = :iasgn
      assignment[1] = aliased_field
      load_temp = Sexp.new
      load_temp[0] = :lvar
      load_temp[1] = temp_symbol
      assignment[2] = load_temp
      block[block.length] = assignment
    end
  else
    # do nothing
  end
end end
     private


attr_reader :ast

           end