interesting. in ruby: ra:~$ irb irb(main):001:0> defined? a => nil irb(main):002:0> defined? b => nil irb(main):003:0> a = b NameError: undefine

interesting. in ruby: ra:~$ irb irb(main):001:0> defined? a => nil irb(main):002:0> defined? b => nil irb(main):003:0> a = b NameError: undefined local variable or method `b' for main:Object from (irb):3 irb(main):004:0> a => nil irb(main):005:0> b NameError: undefined local variable or method `b' for main:Object from (irb):5 irb(main):006:0> defined? a => "local-variable" irb(main):007:0> 'a' gets defined.