Google Summer of Code

PB schizophonic at
Fri Jun 10 08:39:50 PDT 2005

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.


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