From: dblack@...
Date: 2003-01-10T09:27:01+09:00
Subject: Re: attr_reader/writer vs. attr_accessor w/ access control

Hi --

On Fri, 10 Jan 2003, Tom Sawyer wrote:

> 	public
> 	privatize writers attr_accessor :x, :y
> 	protect readers attr_accessor :a, :b
>
> 	private
> 	publicize attr_accessor :n, :w => :to_s
>
> 	etc.
>
> examine the first example. i modified #attr_accessor to additionally return
> the method symbols it creates:
>
> 	attr_accessor :x, :y   #--> [:x, :x=, :y, :y=]
>
> then #writers filters those to return only the ones with equals on the end:
>
> 	writers [:x, :x=, :y, :y=]   #--> [:x=, :y=]
>
> and of course privatize make these two setter methods private.
>
> ah, i like this. only a couple questions left. 1) what's the best way to
> encode what i've done above (i think what i have may be too long winded) and

You could do:

  attr_accessor :a, :b, :x, :y
  private :x=, :y=
  protected :a, :b

which is shorter and (I find) easier to read.  I think there's a bit
of a diminishing return, in terms of clarity, in wrapping wrappers in
wrappers beyond a certain point.

> 2) given this approach, under what circumstances would one ever need
> attr_reader and attr_writer?

Well, if your approach is to write and use a different set of
method-creation shortcuts, then possibly never :-)  They're awfully
nice and concise though.


David

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