From: "Brian Schröder" <ruby.brian@...>
Date: 2005-10-26T02:20:13+09:00
Subject: Re: Comparing Classes with Case ?

On 25/10/05, Patrick Gundlach <clr8.10.randomuser@spamgourmet.com> wrote:
>
>
> > Just throwing in that it would not be a "BIG LOSS", not even a _big
> > loss_ or a big loss, because you nearly never should test for the
> > class of an object.
>
> Well, is the following the rare case of 'nearly never' or just
> stupidity?
>
>
> --------------------------------------------------
> #!/opt/ruby/1.8/bin/ruby -w
>
> class AnonUser        ; end
> class RegularUser <  AnonUser    ; end
> class Developer   <  RegularUser ; end
> class Guru        <  Developer   ; end
> class Sysop       <  Guru        ; end
>
> brian=Guru.new
>
> # ...
>
> if Developer===brian
>   puts "ok, you are Developer"
> end
> if Sysop===brian
>   puts "you may shutdown the server"
> end
> --------------------------------------------------
>
> # -> ok, you are Developer
>
>
> Patrick
>
>

One thing that may be bad about this approach is that you can't have
multiple inheritance. You should at least use modules extending a User
class, so that you allow for a more interesting hirarchie. And I don't
see why User should not have a set of properties and methods like

    * developer?
    * sysop?

etc. (Created dynamically, naturally :-)

That are my thoughts about the approach.

if user.developer?
  ###
elsif user.sysop?
  ###
end

reads better in my opinion.

regards,

Brian

--
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