Google Summer of Code

Hendrik Boom hendrik at
Fri Jun 10 10:01:20 PDT 2005

On Fri, Jun 10, 2005 at 05:39:50PM +0200, PB wrote:
> Massimo Dentico wrote:
> >Note that the Liskov Substitution Principle (LSP), that I called harshly
> >"sacred" on another mailing-list, 
> What is so strange with the substitution principle,
> be it in the Liskov variant or in my granny's variant?
> It just says that, if you want to replace A with A'
> in contexts C1, C2, C3, then A' must have the same
> interface *and semantics* of A, but just in contexts
> C1, C2, C3. In C4 it can do whatever it wants - granted
> that everybody is aware of the dogma "ye shalt NEVER put
> replace A with A' in context C4". It is a "blame you,
> blame me" crystal-clear principle of sheer commonsense.
> The fact it is seldom respected - better, that is
> seldom *understood*, is sheer nonsense.

It should be clear to *anyone* that bothers to think about the matter.
Unfortunately the world is filling up with people who don't.
People who concern themselves only with what something
does, not what it is supposed to do.  How such people can
program mystifies me.

-- hendrik

> Pietro

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