hash constant example

hash_constant.rb

irb(main):017:0> HASH = { a: a, b: b }
=> {:a=>#<Object:0x007f892b9a3b00>, :b=>#<Object:0x007f892b940af0>}
irb(main):018:0> HASH[:a] = Object.new
=> #<Object:0x007f892b9c3b58>
irb(main):019:0> HASH
=> {:a=>#<Object:0x007f892b9c3b58>, :b=>#<Object:0x007f892b940af0>}
irb(main):020:0> HASH[:c] = Object.new
=> #<Object:0x007f892b9d1b18>
irb(main):021:0> HASH = {}
(irb):21: warning: already initialized constant HASH
(irb):17: warning: previous definition of HASH was here
=> {}
irb(main):022:0>