[Newbies] isKindOf considered questionable

[stan shepherd]

matthewf wrote:
> 
> On Sat, Jun 21, 2008 at 08:13:48AM -0700, stan shepherd wrote:
>> 
>> Hi, I'm using isKindOf as part of my unit tests,
>> 
>> self should: [(mare maternalStrand at: 100)
>> 								isKindOf: Gene];
>> 
>> When I run through the code critics, isKindOf is flagged as a
>> 'questionable
>> message'. I can't find any reference to why it should be so; can someone
>> explain please?
> 
> It is considered bad when isKindOf: is used in the following
> way:
> 
> (anObject isKindOf: String) ifTrue: [anObject size]
> 
> It is good design to let an object decide what to do when it
> recieves a message, rather than using isKindOf: to decide
> whether you should send an object one message and not another.
> The reason being that, someone may want to use a different kind
> of object that respects the String protocol.
> 
> Objects are better classified by what messages they respond to,
> not what class they may be.
> 
> For unit tests, this is a good use for it, though.
> 
> -- 
> Matthew Fulmer -- http://mtfulmer.wordpress.com/
> 
> 

Thanks,   that makes sense.
...Stan
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