From: David Alan Black <dblack@...>
Date: 2001-08-15T03:21:51+09:00
Subject: [ruby-talk:19716] Re: class methods and optimizing

Hello --

On Wed, 15 Aug 2001, Chris Moore wrote:

> The last one here is easy... I remember from somewhere that self is the
> default object.  So can I remove it from class definitions completely and
> it's just there to save confusion while reading? (Sorry brain on the
> fritz....*bang* *bang*....)

You can usually do without it, but not always.  In particular, you
need it when you're doing assignments that might involve local
variables or might be "=" methods.  Here are some examples:

   class A
     attr_accessor :thing
     def initialize(n)
       thing = n    # local var; you need self.thing= or @thing =
     end

     def talk
       puts thing   # ok because no assignment preceded it
     end

     def localtalk
       thing = "I'm a local var"
       puts thing   # assignment means this is a local 'thing'
     end

     def weirdtalk
       puts thing        # that's the method thing()
       thing = "weird!"  # assignment creates local var!
       puts thing        # which is this 'thing'
     end

     def myclass
       puts self.class  # just "class" won't parse
     end
   end

   a = A.new(123)
   a.talk            # => nil
   a.thing = "hi"
   a.talk            # => hi
   a.localtalk       # => I'm a local var
   a.weirdtalk       # => hi
		     #    weird!


Amendations, clarifications, further cases welcome.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav