Ruby: shallow copy surprise!

Re:Ruby: shallow copy surprise! by aarongough on Thursday May 20, 2010 @01:33PM (#1364591)

No worries, thanks for taking the time to write it out. I'm glad that I wrote the post (and that I'm getting hammered a little for my assumptions) because making mistakes is probably the only way I'm going to get a deeper understanding of the language...

One thing that confused the issue a little for me is the fact that some objects in Ruby are actually only really 'pretend objects'. ie:

  >> test = 4
  => 4
  >> test2 = 4
  => 4
  >> test.object_id
  => 9
  >> test2.object_id
  => 9

I don't know enough about the deeper parts of the language to know what else there is that's like this though...

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Re:Ruby: shallow copy surprise! by bschaefer on Thursday May 20, 2010 @07:43PM (#1365891)

This is a performance optimization for common (read: integer) numbers: http://ruby-doc.org/core/classes/Fixnum.html

  >> ((1 << 30) - 1).class
  => Fixnum
  >> ((1 << 30)).class
  => Bignum

  >> ((1 << 30) - 1).object_id
  => 2147483647
  >> ((1 << 30) - 1).object_id
  => 2147483647

  >> (1<<30).object_id
  => 166070
  >> (1<<30).object_id
  => 161200

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