~/Untitled.html

#
# setting local vars via eval:
#
#   many libraries go through hoops to create a 'locals' kind of functionality
#   that exposes local variable to a dsl or template,  here's a technique to
#   setup 'true' locals prior to an intance eval or method call.
#
  class Object
    def scope
      lambda{ binding }
    end
  end

  class View
    def initialize template
      @template = template
    end

    def render locals = {}
      context = scope
      locals.each do |k, v|
        var = k
        value = "ObjectSpace._id2ref #{ v.object_id }"
        definition = "#{ var } = #{ value }"
        eval definition, context
      end
      double_quoted_heredoc = ['<<__template__', @template, '__template__'].join("\n")
      eval double_quoted_heredoc, context
    end
  end

  view = View.new '<body> #{ x + y } </body>'

  puts view.render(:x => 40, :y => 2)  #=> <body> 42 </body>