eval_template.rb

来自「ruby on rails web敏捷开发之路第二版 源代码」· RB 代码 · 共 36 行

#---
# Excerpted from "Agile Web Development with Rails, 2nd Ed."
# We make no guarantees that this code is fit for any purpose. 
# Visit http://www.pragmaticprogrammer.com/titles/rails2 for more book information.
#---
class EvalTemplate

  def initialize(view)
    @view = view
  end

  def render(template, assigns)
    # create an anonymous object and get its binding
    env  = Object.new
    bind = env.send(:binding)

    # Add in the instance variables from the view
    @view.assigns.each do |key, value|
      env.instance_variable_set("@#{key}", value)
    end

    # and local variables if we're a partial
    assigns.each do |key, value|
      eval("#{key} = #{value}", bind)
    end

    @view.controller.headers["Content-Type"] ||= 'text/plain'

    # evaluate each line and show the original alongside
    # its value
    template.split(/\n/).map do |line|
      line + " => " + eval(line, bind).to_s
    end.join("\n")
  end
end