From: Tim Pease <tim.pease@...>
Date: 2007-07-04T03:18:48+09:00
Subject: Re: private method clarification, please

On 7/3/07, Gregory Brown <gregory.t.brown@gmail.com> wrote:
> On 7/3/07, Tim Pease <tim.pease@gmail.com> wrote:
> > Is this behavior expected?
> >
> >
> > $ cat t.rb
> > class C
> >   def meth1() private_method end
> >   def meth2() self.private_method end
> >   def private_method() puts 'you called?' end
> >   private :private_method
> > end
> >
> > c = C.new
> > c.meth1
> > c.meth2
> >
> > $ ruby --version
> > ruby 1.8.5 (2006-12-25 patchlevel 12) [i386-cygwin]
> >
> > $ ruby t.rb
> > you called?
> > t.rb:3:in `meth2': private method `private_method' called for
> > #<C:0x442fdd4> (NoMethodError)
> >         from t.rb:10
> >
> >
> > It seems distinctly strange to me that you cannot call a private
> > method using the self semantics shown in meth2. Is this the expected
> > behavior?
>
> Hmm... I can't decide is it's strange or not.  I always think of using
> self.whatever in methods as using 'external' access, in which case,
> it's not surprising.  You can of course, send() through.
>
> So yeah, I can see where that behaviour might seem surprising but it's
> not particularly surprising to me.
>

The only reason it seems strange is that you can use the self
semantics in some cases -- i.e. when calling a setter method

class C
  def meth3( val ) self.private_setter = val end
  def private_setter=( val ) puts "you said '#{val}'" end
  private :private_setter=
end

c = C.new
c.meth3( 'hello' )       #=> you said 'hello'


So, that case works, but others do not. Just seems strange.

TwP