From: Daniel N <has.sox@...>
Date: 2010-04-12T10:13:26+09:00
Subject: Re: attr_accessor, but for a boolean

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On 12 April 2010 11:10, Aaron Patterson <aaron@tenderlovemaking.com> wrote:

> On Mon, Apr 12, 2010 at 10:00:06AM +0900, Albert Schlef wrote:
> > Let's say I have this code:
> >
> > class Mambo
> >   attr_accesstor :safe
> > end
> >
> > Now,
> >
> > 'safe', in my case, is a boolean. Problem is, the getter will be named
> > 'safe', whereas I want it to be 'safe?'.
> >
> > In other words, how do I make the getter 'safe?' and the setter 'safe'
> > ?
>
> In situations like this, I make two "getters" and leave the assignment
> alone.  Other ruby programmers expect your "setters" to be in the form
> of "obj.safe = true", not "obj.safe(true)".
>
> Try something like this:
>
>    class Mambo
>      attr_accesstor :safe
>       alias :safe? :safe
>    end
>
> Here it is in action:
>
>    irb(main):001:0> class Mambo
>    irb(main):002:1>   attr_accessor :safe
>    irb(main):003:1>   alias :safe? :safe
>    irb(main):004:1> end
>    => nil
>    irb(main):005:0> m = Mambo.new
>    => #<Mambo:0x000001010cab50>
>    irb(main):006:0> m.safe = true
>    => true
>    irb(main):007:0> m.safe?
>    => true
>    irb(main):008:0>
>
> --
> Aaron Patterson
> http://tenderlovemaking.com/


Unfortunately this doesn't support safe? being boolean always.  It could be
something other than true false (may not be a problem)

If you want to use attr_accessor rather than simply aliasing the method I'd
suggest

def safe?
  !!safe
end

This way the expectation of a ? method to return a boolean is preserved.

Cheers
Daniel

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