From: Robert Klemme <shortcutter@...>
Date: 2008-04-25T06:25:03+09:00
Subject: Re: inverse OOP

On 24.04.2008 12:15, Eleanor McHugh wrote:
> On 24 Apr 2008, at 10:40, Martin Vales wrote:

>> I have always had a doubt about OOP.
>> Usually we have a parent and several child, but what happen if we need
>> the inverse system. for example DBI/DBD APIs.??
>>
>> I need build map proyections and i want and intermediate API for all
>> proyections clases.

What exactly do you mean by "intermediate"?  Do you mean that all 
projections should have the same interface?  For that you do not need 
inheritance at all - at least in Ruby.  Or do you rather mean that they 
share behavior (implementation)?

>> All map proyections have the same methods (geodetic_to_projected and
>> projected_to_geodetic)
> 
> Then define either a projection class from which they all inherit, or  
> a projection module which they all include.

Nice reading from you again, Ellie. :-)

I was going to also suggest the module approach.  But I do wonder why 
Martin chose to call it "inverse OOP".  It seems the more appropriate 
term would be "multiple inheritance" or am I missing something?

Cheers

	robert