From: Matthew B Gardner <weather@...>
Date: 2007-08-19T00:37:26+09:00
Subject: Re: Problem with Array#delete

> I went a little different route, but that was indeed the problem. I just 
> defined == in my class, which I guess was comparing the class of the object 
> instead of the object_id. I did:
> 
> def == obj
> ������self.equal?(obj)
> end

Ok, so it looks like this didn't work so well after all. Initially, I thought 
it did because I reloaded the character.rb file while the program was running 
and it worked fine. However, when I shutdown the program and started it back 
up, I experienced the same problem (though it again worked after reloading 
the file). I'll post all the necessary code:

def world
	returns the world object
end

class World
	def initialize
		characters = []
	end
end

class Account
	def foo
		@character = Character.new()
		world.characters << @character
	end
end

class Character
	def quit
		p self.object_id
		p world.characters.class
		p world.characters.size
		world.characters.each do |ch|
			p ch.class
			p ch.object_id
		end
		world.characters.delete(self)
		p world.characters
	end
end

This is the output from Character#quit, with two character objects in the 
world#characters array:

-607170236
Array
2
Character
-607170236
Character
-607240286
[]

As you can see, both Character objects are being deleted when only the first 
should be (at least as far as my intention). In an attempt to fix this, I 
added the following method:

class Character
	def == obj
		self.equal?(obj)
	end
end

I thought this did fix it, because I reloaded the file and tested it -- and it 
only deleted the targeted object. However, when I restarted the program, it 
didn't work and deleted both objects again. Without changing anything, and 
just reloading the file while the program was still running, it worked as 
intended again and deleted only the targeted object.

I have an Account class that utilizes World#accounts (an Array object) in the 
exact same way that Character utilizes World#characters, and the deletion of 
accounts works fine.

Robert, thank you for your reply -- I hope that this answers the noted 
questions that you had, and maybe even provides some more insight into what 
the problem might be. Is there an explanation for why the Character#== method 
works after being reloaded, but not at start time? Also, Robert, I reviewed 
the portion of your reply regarding a Struct object, and it doesn't look like 
it would be beneficial in my case -- I'm just trying to add and delete single 
instances of a class from an array -- but I could be wrong?

Thanks again for any help,
Matt