From: Jian Lin <blueskybreeze@...>
Date: 2010-05-20T11:24:07+09:00
Subject: method returning a hash, is the hash in the heap?

For this program:

class Point
  def initialize(x,y)
    @x,@y = x,y
    @something = 123.456
  end

  def instance_variables_and_values
    hash = {}
    instance_variables.each {|n| hash[n] = instance_variable_get(n)}
    return hash
  end

end

p1 = Point.new(1,2)
p p1.instance_variables_and_values

p2 = Point.new(3,4)
p p1.instance_variables_and_values
p p2.instance_variables_and_values

so the hash is actually allocated in the Heap, and the local variable in
the Stack is just the "hash" reference?

So when the method returns, the "hash" variable, which is just a
reference to the hash object, is destroyed.  But the hash object that is
in the Heap will stay as long as there is a reference to it (a reference
from outside)?
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