eval_api_类中类_map

（一）eval("a=1;b=2;puts a+b")

运行结果vagrant@vagrant-ubuntu-trusty-64:/vagrant/test_project$ ruby Apple4.rb3

（二）查看apiReference Documentation就是API

（三）类中类及类中类之方法

class Fruit  COLOR='red'  class Apple    COLOR='red'    def size      puts 'big'    end  endendputs Fruit::Apple::COLORputs Fruit::Apple.new.size
运行结果

vagrant@vagrant-ubuntu-trusty-64:/vagrant/test_project$ ruby Apple4.rbredbig
（四）map用法
result=[1,2,3].map do |e|  e*eendputs result.inspect