On 24 Apr 2008, at 10:40, Martin Vales wrote: > Hi: > > 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. > > 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. Ellie Eleanor McHugh Games With Brains http://slides.games-with-brains.net ---- raise ArgumentError unless @reality.responds_to? :reason