From: Jim Weirich <jweirich@...>
Date: 2003-11-28T02:24:31+09:00
Subject: Re: Method wrapping

T. Onoma wrote:

> Actually I have rethought this. Wrappers do depend on the implementation b/c 
> their proper functionality depends on *what* is returned, not just what 
> *kind*. They may not raise an error if the kinds are the same, but that 
> doesn't mean they work right. So my original wording was more correct.

The distinction between *what* and *kind* alludes me for the moment. 
However, I would tend to suspect that a wrapper depends upon the primary 
method in the same way client software depends upon the methods it 
calls.  In other words, they depend upon the arguments, return value and 
semantics (as defined by a DbC style contract), but not upon actual 
implementation.

I would suspect that most method replacements would honor the same 
argument lists, return types and basic semantics.  Otherwise replacing a 
method would cause *everyone* who calls that method to be modified, not 
just the wrapper methods.

-- 
-- Jim Weirich       jweirich@one.net      http://onestepback.org
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"Beware of bugs in the above code; I have only proved it correct,
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)