From: John Carter <john.carter@...>
Date: 2005-08-02T08:11:09+09:00
Subject: C++ Design Principles for Ruby - Some classes don't want kids.

Avoid inheriting from concrete classes, to add behaviour add non-member 
functions, to add state use composition.

In ruby I would change this to..

To add behaviour, don't be shy, in Ruby you can always extend a concrete 
class when you need to.

eg.

class String
   def my_nifty_func
   end
end

To add state, I agree with them, use composition. Why? Unless you cover 
every use of String, you may have an operation somewhere that 
accidentally loses that extra state.




John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
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Carter's Clarification of Murphy's Law.

"Things only ever go right so that they may go more spectacularly wrong later."

From this principle, all of life and physics may be deduced.