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Re: OO should break when broken(was re: the benefits of immutability)
On Monday, September 1, 2003, at 06:14 AM, Colin Putney wrote:
> An ellipse is a circle with additional capabilities - it can have
> different radii along each of its dimensions.
This reminds me of something that bothers me about OO: the
accumulation of unused stuff. When I extend Circle to make Ellipse, I
add x-radius and y-radius, but the original radius instance variable is
still there. Since I'm not going to use Circle's radius any more, I
wish I could just ask it to go away, if the compiler or runtime could
verify it isn't needed by methods I decide not to override.
Geoffrey
P.S. Thanks for the Smalltalk example. It reminds me of an era of
lightweight expression and immediate interoperability.
--
Geoffrey S. Knauth | http://knauth.org/gsk