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From: limsoon@saul.cis.upenn.edu (Limsoon Wong)
Newsgroups: comp.std.c++
Subject: the most dissatisfying part of c++
Message-ID: <27634@netnews.upenn.edu>
Date: 31 Jul 90 14:46:47 GMT
Sender: news@netnews.upenn.edu
Reply-To: limsoon@saul.cis.upenn.edu.UUCP (Limsoon Wong)
Organization: University of Pennsylvania
Lines: 26


the program below is a contrived one.   it cannot  be compiled.
the reason is a type fault. however, it exhibits a very central
characteristic of update.    something should be  done to allow
this kinds of programs.	   			    ---limsoon.



#include <stream.h>
class a { 
  public: 
    a& test() { 
	// do some modification to the state of this object,
	// then ...
	return *this;
};
class b : public a { 
  public:
    int b;
};
main() { 
  b B; 
  B = B.test();
  // type violation despite the fact that 
  // `B' and `B.test()' are the same object.
}