From: "Weirich, James" <James.Weirich@...>
Date: 2003-11-20T07:33:14+09:00
Subject: Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata	 about attribute types)

Sean O'Dell writes:

> > Actually, it tells you exactly.  If a class inherits from String, you
know it 
> > has all the methods String does, and you know exactly what parameters
they 

Charles Hixson writes:

> No, you don't know that at all.  It's a reasonable 
> presumption, but any, or all, or the methods that you think 
> are there might have been overridden.  And might do something 
> totally different.  And this may be for either a good reason 
> or a silly reason.

Several people have said this, and although true, this is not my main
concern and if people make an object non-LSP compliant, then they get what
they deserve.

However, my concern is the insistence that only those things that have
String in their ancestry can have string like behavior and can be passed to
functions expecting a string like object.

And this is what I thought Sean was saying (i.e. advocating ancestry
checks).

I now think what Sean is some way of "marking" a class to indicate that in
implements a particular protocol.  That marking could be through
inheritance, but could also be done by some alternate mechanism.

This (IMHO) is not nearly as onerous as ancestor checking.  But I'm not
convinced of its utility yet.  I'll have to think about this.

Sean, did I capture your thoughts accurately?  Or am I still missing
something.

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