From: Josh Cheek <josh.cheek@...>
Date: 2010-04-12T15:54:41+09:00
Subject: Re: attr_accessor, but for a boolean

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On Mon, Apr 12, 2010 at 12:35 AM, Albert Schlef <albertschlef@gmail.com>wrote:

> Albert Schlef wrote:
> > Thank you both. I wanted to make sure there's no built-in way to do
> > this.
>
> Hey, I've just discovered that 'ri' tells me that Module has an
> 'attr_reader?' method that creates a question-mark attribute.
>
> Problem is, 'ri' displays methods from everything I've installed on my
> system, so I can't know if 'attr_reader?' is provided by Ruby itself or
> by some wacky gem.
> --
> Posted via http://www.ruby-forum.com/.
>
>
Doesn't work for me, so probably from some gem.

You could do something like this:

class Module
  def attr_accessor?(*methods)
    methods.each do |method|
      ivar = "@#{method}"
      define_method("#{method}=") { |value| instance_variable_set ivar ,
value }
      define_method("#{method}?") { !!instance_variable_get(ivar) }
    end
  end
end


class Example
  attr_accessor? :abc
end

e = Example.new
e.abc = true
e.abc? # => true

e.abc = false
e.abc? # => false

e.abc = 1
e.abc? # => true

e.abc = nil
e.abc? # => false

e.abc = :adsf
e.abc? # => true




There was also a ruby quiz about attr methods
http://rubyquiz.com/quiz67.html And there is a gem based off of it
http://github.com/ahoward/fattr

I don't know where yours came from, though.

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