From: Yochen Gutmann <yoche2001@...>
Date: 2006-08-08T05:37:14+09:00
Subject: Re: How to react on nil or wrong object-type as parameter

So if I do understand you all correctly, in Ruby you put the responsible 
to the caller of a method (eg print_salary()). If you want to test that 
method, you test it only with the proper types. The next thing would be 
testing the method which includes the call of print_salary() if it calls 
this methods with the wrong types of parameter. Is this right?

One problem in this concept is that if some operations might work on a 
parameter-object and the following is not the exception is thrown when 
the object is already modified.

class Bank
   @invitations_to_golf

   def handle_client_well client
      client.decrease_acoount(200)
      client.check_portfolio
      @invitations_to_golf.push client
   end

end

jon_doe = LowBudgetClient.new
big_boss = VeryRichClient.new
big_money = Bank.new

big_money.handle_client_well big_boss
big_money.handle_client_well jon_doe // poor guy has no portfolio

So, when the hcw-method is called with jon_doe, he has to pay for better 
handling but since he has no portfolio the exception is thrown before he 
is entering the golf course.

One solution might be a exception around the method-body (yes, again 
;-)) and a include an ensure to increase the account again if something 
broke. But again, this procedure would fail if there are many modifing 
operations.

Perhaps I am still thinking too Java'ish and these are high theorectical 
problems or I still dont get it.

Yochen

-- 
Posted via http://www.ruby-forum.com/.