From: "Iñaki Baz Castillo" <ibc@...>
Date: 2011-05-01T06:58:57+09:00
Subject: Re: Why defining a constant in a method is not allowed but using self.class.const_set is allowed?

2011/4/30 7stud -- <bbxx789_05ss@yahoo.com>:
> "Iñaki Baz Castillo" <ibc@aliax.net> wrote in post #995996:
>>
>> Ok. Then one question more: why is not possible to reassing a value to
>> a constant
>
> Why do you want to change a *constant*?  ruby has variables for that.

Because it's more efficient. Consider this example:


module M
  class C
    KAKA = 123

    def self.kaka
      @kaka ||= 123
    end
  end
end

# Let's initialize @kaka:
M::C.kaka
=> 123

$kaka = 123

--------------------------------

Benchmark.realtime { 10000000.times { M::C::KAKA } }
=> 0.9098186492919922

Benchmark.realtime { 10000000.times { M::C.kaka } }
=> 1.9608278274536133

Benchmark.realtime { 10000000.times { $kaka } }
=> 0.9143557548522949



-- 
Iñaki Baz Castillo
<ibc@aliax.net>