From: Igor Pirnovar <lists@...>
Date: 2013-04-01T15:16:13+09:00
Subject: Re: Private setters can be called by self, why not getters?

Josh Cheek wrote in post #1103861:
> (b/c I was going to recommend making these protected instead of private,
> in order to avoid this issue).
>
> -Josh

You are right, making these protected instead of private seems to be the
best solution, unless you need to shield access to your getters and
setters from subclasses too. Taking into account, that instance
variables in Ruby are by design public, all this accessor encapsulation
is rather 'non-ruby-ish', nevertheless, your suggestion deserves to be
noticed!

The following code works exactly as expected, and you can even use only
the simplest form of accessor declaration {{ attr_accessor :count }} in
the private section, without bothering to separate the getter from the
setter method.

  --------------------------------------------------------------------
  #!/usr/bin/env ruby
  class Counter
    def initialize; self.count = 0; end
    def show_count; puts "Count=#{count}"; end
    def increment1; self.count = count + 1; end
    def increment2; self.count = self.count + 1; end
    def increment3; self.count += 1; end
   protected
    attr_accessor :count
  end

  o = Counter.new
  o.show_count  #=> Count=0
  o.increment1
  o.show_count  #=> Count=1
  o.increment2
  o.show_count  #=> Count=2
  o.increment3
  o.show_count  #=> Count=3

  puts "Explicit get: Count=#{o.count}"  #=> fails with exception
  o.count=1234        #=> would properly fail too
  --------------------------------------------------------------------

Very good, Josh!
Regards, igor

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