From: Austin Ziegler <austin@...>
Date: 2003-11-21T04:41:25+09:00
Subject: Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata about attribute types) )

On Thu, 20 Nov 2003 16:02:14 +0900, Thien Vuong wrote:
> Austin Ziegler wrote:
>>> I do wonder what functional purpose does "kind_of?" serves now
>>> that it was severely denigrated in the language - should it be
>>> deprecated/ removed? since it is considered totally bad style to
>>> use.
>> I don't think that it's totally useless. I do think that it's of
>> extremely limited utility.
> Could you give me an example of what is considered a good use
> then? Given the presumption that object classification and
> knowledge is bad, what good information could be gained from
> knowing it?

Note that what follows is my opinion only:

* Checking against your own types. See Ruwiki's lib/ruwiki.rb lines
  81 and 193.
* Distinguishing between Array, Hash, and String in times when such
  distinctions are necessary (e.g., #each).
* This example from MIME::Type:

  def <=>(other) #:nodoc:
    if other.respond_to?(:content_type)
      @content_type <=> other.content_type
    elsif other.kind_of?(String)
      @simplified <=> Type.simplified(other)
    else
      @content_type <=> other
    end
  end

There's not a lot of examples where I use #kind_of? in my code.

-austin
--
austin ziegler    * austin@halostatue.ca * Toronto, ON, Canada
software designer * pragmatic programmer * 2003.11.20
                                         * 14.18.00