def anonymous_function(block)
      lambda do |*args|
        # args: (this, node) v8 >= 0.10, otherwise (node)
        raise ArgumentError, "missing node" if args.empty?
        @tree[:Anonymous].new block.call(@tree, args.last)
      end
    end
def anonymous_function(block)
      lambda do |*args|
        # args: (this, node) v8 >= 0.10, otherwise (node)
        raise ArgumentError, "missing node" if args.empty?
        @tree[:Anonymous].new block.call(@tree, args.last)
      end
    end
Creates a JavaScript anonymous function from a Ruby block