automatic subtyping/intensions
William Tanksley
wtanksle@UCSD.EDU
Tue, 9 Feb 1999 10:08:15 -0800 (PST)
On 9 Feb 1999, Laurent Martelli wrote:
>>>>>> "Tril" == Tril <dem@tunes.org> writes:
> >> 1 - B. Liskov and J. Wing: "A Behavioral Notion of Subtyping",
> >> ACM Transactions on Programming Languages and Systems, Number
> >> 16(6), pp. 1811-1841, ACM Press, 1994.
> Tril> Could you summarize the content of the article? What is
> Tril> meant by a "behavioral notion?"
>It means that a type A is a subtype of B if objects of type A behave
>exactly the same way as objects of type B. This is the LSP (Liskov
>Substitution Principle) : if a function says it wants an argument of
>type B, you can give it an object of type A, and it wont see the
>difference. This definition does not rely on the name of understood
>messages but rather on their semantic.
Does this article actually tell how to achieve this, or is it just another
one saying how *nice* it would be if we could ...?
>Laurent
-Billy