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From: rick@tetrauk.UUCP (Rick Jones)
Newsgroups: comp.lang.eiffel
Subject: Re: Multiple creation routines.
Message-ID: <1057@tetrauk.UUCP>
Date: 14 Dec 90 10:02:38 GMT
References: <4106@tantalum.UUCP> <1045@tetrauk.UUCP> <4212@tantalum.UUCP> <1051@tetrauk.UUCP> <462@eiffel.UUCP>
Reply-To: rick@tetrauk.UUCP (Rick Jones)
Organization: Tetra Ltd., Maidenhead, UK
Lines: 26

Thank you to Kim Rochat for re-posting Bertrand Meyer's original article.  It
appears that I completely missed all the previous discussion on this, I think
it was shortly before I started receiving News.  It seems to address a lot of
the points I have raised recently.

I have one query though.  The proposed syntax allows an object to be created
using the form:

	x !!

meaning create an "empty" object.  It may be quite incorrect for an object of
the class in question to be in such a state - i.e. the invariant would be
violated.  However, there seems to be nothing syntactically to prevent a client
program from doing this, so correctness would rely entirely on invariant
checking in the target class.  This is a retrograde step from the current
situation, where a call to the create routine at least has to provide the
proper arguments.

It would seem that the "creation" clause needs some way of specifying whether a
default creation call is valid or not.

-- 
Rick Jones
Tetra Ltd.  Maidenhead, 	Was it something important?  Maybe not
Berks, UK			What was it you wanted?  Tell me again I forgot
rick@tetrauk.uucp					-- Bob Dylan