From: Adam Gardner <adam.oddfellow@...>
Date: 2009-04-02T07:02:07+09:00
Subject: Re: When to use instance variables @

Steve Dogers wrote:
> Thank you to everyone who answered - yes it makes a lot more sense now!
> 
> It made me think though - when should you use self? I know you can use 
> self to declare class methods but why do I see some people prefix just 
> about anything with self. ? Isn't 'self' implied?
> 
> Cheers!

I for one sometimes prefix methods with self to help visually 
distinguish them from local variables. I did this a lot when I was less 
experienced in ruby, and I still do it occasionally. You must specify 
the self receiver if you're calling an assignment method, or the 
interpreter will think you are trying to assign to a local variable. 
It's also mandatory if you have a method with the same name as a local 
variable, or whose name begins with a capital letter (although frankly, 
you probably should just change the method name or the variable name in 
these cases):

hello = 1

def hello
  2
end

hello # => 1
self.hello # => 2

def Hello
  3
end

Hello # => NameError: uninitialized constant Hello
self.Hello # => 3


I've often thought that the ruby would be just a tad bit cleaner if 
local variables and implicit self method calls were distinguishable from 
each other syntactically. Something like giving implicit self method 
calls a bare dot prefix. I'm sure there are a lot of people who would 
disagree, though, and it's unlikely to happen at this point regardless. 
Ah, well.
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