From: Gavin Kistner <gavin@...>
Date: 2004-01-30T08:39:54+09:00
Subject: Re: Why is  def foo?  legal but  @foo?  illegal?

Chris Morris wrote:
>>     attr_reader(:foo?)
>>     def initialize
>>         @foo?=true
>>     end
> 
> [...] but I know the above won't work because 
> you used attr_reader which will create a getter, but no setter for foo?. 

What? You don't need a public setter function to set the value of an 
instance variable. That's the whole point of attr_reader :)

For example, the following code works just fine:

	class Bar
		attr_reader(:foo)
		def initialize
			@foo=true
		end
	end
	
	bar = Bar.new
	puts bar.foo


as does this code:

	class Bar
		def initialize
			@foo=true
		end
		def foo?
			return @foo
		end
	end
	
	bar = Bar.new
	puts bar.foo?

My only point is that if I could name an instance variable @foo? then 
the code quoted at the top of this post would work, and be slightly less 
verbose.

I suppose it's not allowed because you can define a method named foo? 
but not one named foo?= (thus enforcing the idea that a method ending in 
a question mark is for querying a boolean aspect of an instance, and not 
for setting one) and you might want to be able to publicly set the state 
of a @foo? variable.

--
(-, /\ \/ / /\/